WO2024087398A1 - Transformer-based battery heating circuit, and electric vehicle - Google Patents

Transformer-based battery heating circuit, and electric vehicle Download PDF

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Publication number
WO2024087398A1
WO2024087398A1 PCT/CN2023/070779 CN2023070779W WO2024087398A1 WO 2024087398 A1 WO2024087398 A1 WO 2024087398A1 CN 2023070779 W CN2023070779 W CN 2023070779W WO 2024087398 A1 WO2024087398 A1 WO 2024087398A1
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Prior art keywords
battery
transformer
sub
heating
circuit
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PCT/CN2023/070779
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French (fr)
Chinese (zh)
Inventor
夏铸亮
喻皓
赵小坤
杨凯诚
万希
胡志华
龚浩然
Original Assignee
广汽埃安新能源汽车股份有限公司
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Publication of WO2024087398A1 publication Critical patent/WO2024087398A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • B60L58/24—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries for controlling the temperature of batteries
    • B60L58/27—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries for controlling the temperature of batteries by heating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L15/00—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles
    • B60L15/007—Physical arrangements or structures of drive train converters specially adapted for the propulsion motors of electric vehicles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L15/00—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles
    • B60L15/20—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the technical field of power batteries, and in particular to a transformer-based battery heating circuit and an electric vehicle.
  • new energy vehicles refer to vehicles that use unconventional vehicle fuels as a power source (or use conventional vehicle fuels and adopt new vehicle power devices), and integrate advanced technologies in vehicle power control and drive to form vehicles with advanced technical principles, new technologies, and new structures.
  • New energy vehicles include pure electric vehicles, hybrid vehicles, etc.
  • the current commonly used battery heating method generally heats the cold zone liquid through positive temperature coefficient resistors (PTC, Positive Temperature Coefficient), electric drive system heat generation, etc., and then the cold zone liquid heats the battery to achieve indirect heating, or the motor winding is charged and discharged through the motor controller, thereby generating an AC current in the battery, and the battery is heated by the heat generated by the internal resistance of the battery, that is, direct heating of the internal resistance of the battery, or self-heating of the battery.
  • PTC Positive Temperature Coefficient
  • the indirect heating method is very inefficient, and a large amount of heat cannot be effectively transferred to the battery and is dissipated into the environment; the heat transfer is slow, and the heat needs to be input into the battery through the cold zone liquid, the external structure of the battery, etc., and the battery temperature rises very slowly; the battery heating is uneven, and the temperature of the battery cell close to the cold zone liquid rises quickly; when the traditional direct heating method using the motor winding is used, the heating current frequency is low, and the direct heating AC current frequency is generally about 2kHz, the human ear is very sensitive, and the noise is very large; this method is not easy to use when the vehicle is in motion, and it is easy to cause torque jitter or affect the motor power output.
  • the purpose of the present application is to provide a transformer-based battery heating circuit and electric vehicle, which can achieve the technical effects of less component heat generation when heating the battery, heating in driving state, and little impact on the motor power.
  • the present application provides a transformer-based battery heating circuit, comprising a battery pack, a transformer, a three-phase inverter, a heating relay, and a three-phase motor;
  • the battery pack comprises a first sub-battery, a second sub-battery, a third sub-battery and a fourth sub-battery, the first sub-battery and the second sub-battery are connected in series to form a first battery half-bridge circuit, the third sub-battery and the fourth sub-battery are connected in series to form a second battery half-bridge circuit, and the first battery half-bridge circuit and the second battery half-bridge circuit are connected in parallel;
  • the transformer is provided with a primary side and a secondary side, the two ends of the secondary side are respectively connected to the midpoint of the first battery half-bridge circuit and the midpoint of the second battery half-bridge circuit, and one end of the primary side is connected to one of the endpoints of a preset endpoint set, and the preset endpoint set includes the midpoint of the second battery half-bridge circuit, the positive pole of the DC bus, the negative pole of the DC bus, the internal level point of the battery, the positive and negative bus capacitor voltage dividing point, the midpoint of the DC bus capacitor, and the second battery half-bridge;
  • the three-phase motor is connected to the other end of the primary side and the three-phase inverter respectively, and the three-phase motor is connected to the transformer through the heating relay.
  • the heating relay when battery heating is required, the heating relay is closed, and no matter whether the vehicle is in a parked or running state, the three-phase current of the three-phase motor is controlled through the PWM modulation of the three-phase inverter, so that the three-phase motor generates corresponding torque (in the driving state, it drives the vehicle to run; when the vehicle is stationary, it outputs zero torque); the PWM modulation of the three-phase inverter will generate a common-mode voltage in the three-phase motor, and the common-mode voltage acts on the transformer and generates an alternating current on the secondary side of the transformer.
  • the alternating current flows through the internal resistance of each sub-battery in the battery pack, and the battery is heated and heated, thereby improving the performance of the battery in a low-temperature environment and enhancing the vehicle's endurance and power; thus, the battery heating circuit can achieve the technical effects of less heating of components when heating the battery, heating in the driving state, and little impact on the motor power.
  • the three-phase inverter includes three power switch tube assemblies, one end of the power switch tube assembly is connected to one end of the first battery half-bridge circuit, and the other end of the power switch tube assembly is connected to the other end of the second battery half-bridge circuit.
  • the power switch tube assembly includes two power switch tubes, and the two power switch tubes are connected in series.
  • the three-phase motor is provided with three cables, and the three cables are respectively connected to the three power switch tube assemblies.
  • the battery heating circuit also includes a capacitor, and the capacitor and the heating relay are connected in series.
  • the battery heating circuit also includes a first relay, which is connected in series to one end of the first battery half-bridge circuit.
  • the battery heating circuit also includes a second relay, which is connected in series to the other end of the first battery half-bridge circuit.
  • the first relay and the second relay are respectively the positive and negative relays of the battery pack.
  • the three-phase motor is a star-connected three-phase motor.
  • the three-phase motor is one of a permanent magnet synchronous motor, a brushless motor, and an asynchronous motor.
  • the present application provides an electric vehicle, comprising the transformer-based battery heating circuit as described in any one of the first aspects.
  • FIG. 1 a is a circuit diagram of a first transformer-based battery heating circuit provided in an embodiment of the present application.
  • FIG1 b is a circuit diagram of a second transformer-based battery heating circuit provided in an embodiment of the present application.
  • FIG. 1c is a circuit diagram of a third transformer-based battery heating circuit provided in an embodiment of the present application.
  • FIG1d is a circuit diagram of a fourth transformer-based battery heating circuit provided in an embodiment of the present application.
  • FIG. 1e is a circuit diagram of a fifth transformer-based battery heating circuit provided in an embodiment of the present application.
  • FIG. 1f is a circuit diagram of a sixth transformer-based battery heating circuit provided in an embodiment of the present application.
  • FIG1g is a circuit diagram of a seventh transformer-based battery heating circuit provided in an embodiment of the present application.
  • FIG. 2 is a simplified model schematic diagram of a transformer-based battery heating circuit provided in an embodiment of the present application.
  • FIG3 is a circuit diagram of a battery heating circuit of a battery stack provided in an embodiment of the present application.
  • FIG. 4 is a circuit diagram of a battery heating circuit with batteries connected in series provided in an embodiment of the present application.
  • FIG5 is a circuit diagram of a first single-cell half-bridge provided in an embodiment of the present application.
  • FIG6 is a circuit diagram of a second single-battery half-bridge provided in an embodiment of the present application.
  • FIG. 7 is a schematic diagram of a circuit in which a primary circuit is connected to one phase of a motor according to an embodiment of the present application.
  • the terms “installed”, “connected”, and “connected” should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements.
  • installed should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements.
  • the embodiment of the present application provides a transformer-based battery heating circuit and an electric vehicle, which can be used in the battery heating process; when battery heating is required, the heating relay is closed, and no matter whether the vehicle is in a parked or running state, the three-phase current of the three-phase motor is controlled through the PWM modulation of the three-phase inverter, so that the three-phase motor generates corresponding torque (in the driving state, drives the vehicle to run; when the vehicle is stationary, outputs zero torque); the PWM modulation of the three-phase inverter will generate a common-mode voltage in the three-phase motor, and the common-mode voltage acts on the transformer and generates an alternating current on the secondary side of the transformer.
  • the alternating current flows through the internal resistance of each sub-battery in the battery pack, and the battery is heated and heated, thereby improving the battery performance in a low-temperature environment and enhancing the vehicle's endurance and power; thus, the battery heating circuit can achieve the technical effects of less component heat generation when heating the battery, heating in the driving state, and little impact on the motor power.
  • FIG. 1a is a circuit diagram of a first transformer-based battery heating circuit provided in an embodiment of the present application.
  • the transformer-based battery heating circuit includes a battery pack 100, a transformer 200, a three-phase inverter 300, a heating relay Ka and a three-phase motor 400.
  • the battery pack 100 includes a first sub-battery U1, a second sub-battery U2, a third sub-battery U3 and a fourth sub-battery U4, the first sub-battery U1 and the second sub-battery U2 are connected in series to form a first battery half-bridge circuit, the third sub-battery U3 and the fourth sub-battery U4 are connected in series to form a second battery half-bridge circuit, and the first battery half-bridge circuit and the second battery half-bridge circuit are connected in parallel.
  • the first sub-battery U1 and the second sub-battery U2 are symmetrical, and the third sub-battery U3 and the fourth sub-battery U4 are symmetrical; the voltages of the first sub-battery U1 and the third sub-battery U3 are the same, and the voltages of the second sub-battery U2 and the fourth sub-battery U4 are the same.
  • the first sub-battery U1 and the second sub-battery U2, the third sub-battery U3 and the fourth sub-battery U4 are connected in series to form two "half-bridge" circuits, and then the two "half-bridge" circuits are connected in parallel to form a "full bridge".
  • the first sub-battery U1 and the third sub-battery U3 have different capacities
  • the second sub-battery U2 and the fourth sub-battery U4 have different capacities, so as to keep the temperature rise consistent.
  • the transformer 200 is provided with a primary side and a secondary side, the two ends of the secondary side are respectively connected to the midpoint of the first battery half-bridge circuit and the midpoint of the second battery half-bridge circuit, and one end of the primary side is connected to one of the endpoints of a preset endpoint set, and the preset endpoint set includes the midpoint of the second battery half-bridge circuit, the positive pole of the DC bus, the negative pole of the DC bus, the internal level point of the battery, the positive and negative bus capacitor voltage divider point, and the midpoint of the DC bus capacitor of the second battery half-bridge.
  • one end of the primary side is connected to the midpoint of the second battery half-bridge circuit; a secondary side of a transformer 200 is connected between the midpoint of the first battery half-bridge circuit and the midpoint of the second battery half-bridge circuit; one end of the primary side of the transformer 200 is also connected to the midpoint of the second battery half-bridge circuit, that is, this end is also connected to the opposite end of the secondary side.
  • the transformer ratio is designed according to the battery voltage, the battery internal resistance, and the battery heating power requirement.
  • a transformer is a device that uses the principle of electromagnetic induction to change the AC voltage. Its main components are the primary coil, the secondary coil and the iron core (magnetic core). The main functions are: voltage conversion, current conversion, impedance conversion, isolation, etc. According to the purpose, it can be divided into: power transformers and special transformers (furnace transformers, rectifier transformers, industrial frequency test transformers, voltage regulators, mining transformers, audio transformers, medium frequency transformers, high frequency transformers, impact transformers, instrument transformers, electronic transformers, reactors, mutual inductors, etc.).
  • the primary side of the transformer 200 refers to the input side of the voltage
  • the secondary side refers to the output side of the voltage after the voltage is converted by the transformer.
  • the three-phase motor 400 is connected to the other end of the primary side of the transformer 200 and the three-phase inverter 300 respectively, and the three-phase motor 400 is connected to the transformer 200 via a heating relay Ka.
  • the circuit can be cut off for protection when the vehicle fails, and on the other hand, the circuit can be cut off to stop battery heating when there is no need to heat the battery.
  • the heating relay Ka is closed, and the three-phase current of the three-phase motor is controlled by the PWM modulation of the three-phase inverter 300 regardless of whether the vehicle is in the parked or running state, so that the three-phase motor 400 generates corresponding torque (in the driving state, drives the vehicle to run; when the vehicle is stationary, outputs zero torque); the PWM modulation of the three-phase inverter 300 will generate a common-mode voltage in the three-phase motor 400, and the common-mode voltage acts on the transformer and generates an alternating current on the secondary side of the transformer.
  • the alternating current flows through the internal resistance of each sub-battery in the battery pack 100, and the battery generates heat and heats up, thereby improving the battery performance in a low-temperature environment and enhancing the vehicle's endurance and power; thus, the battery heating circuit can achieve the technical effects of less component heat generation when heating the battery, heating in the driving state, and little impact on the motor power.
  • pulse width modulation is an analog control method that modulates the bias of the transistor base or the gate of the field effect tube according to the change of the corresponding load to achieve the change of the conduction time of the transistor or the field effect tube, thereby achieving the change of the output of the switching regulated power supply.
  • This method can keep the output voltage of the power supply constant when the working conditions change. It is a very effective technology for controlling analog circuits using digital signals of microprocessors. It is widely used in many fields from measurement, communication to power control and conversion.
  • the three-phase inverter 300 can be controlled using SPWM (sinusoidal PWM modulation), SVPWM (space vector PWM modulation) or other modulation methods, such as DPWM (discontinuous PWM modulation); it should be noted that the PWM modulation method of the three-phase inverter 300 here is only an example and not a limitation.
  • the three-phase inverter 300 includes three power switch tube assemblies, one end of the power switch tube assembly is connected to one end of the first battery half-bridge circuit, and the other end of the power switch tube assembly is connected to the other end of the second battery half-bridge circuit.
  • the power switch tube assembly includes two power switch tubes, and the two power switch tubes are connected in series.
  • the three power switch tube assemblies include six power switch tubes Q1 to Q6 , namely, six semiconductor power switch tubes of the three-phase inverter 300 that drive the three-phase motor 400 to operate.
  • the power switch tube of the power switch tube assembly may be a semiconductor power switch device such as a field effect tube, an insulated gate bipolar transistor, etc.
  • the three-phase motor is provided with three cables, and the three cables are respectively connected to three power switch tube assemblies.
  • the battery heating circuit further includes a capacitor, and the capacitor and the heating relay are connected in series.
  • the transformer 200 is connected to the three-phase motor 400 via a capacitor Cn and a heating relay Ka.
  • the capacitor Cn is used to isolate DC and prevent the transformer 200 from being magnetically saturated, and to resonate with the common mode inductance of the three-phase motor 400 and the leakage inductance of the transformer 200.
  • the transformer 200 is connected to the neutral point of the three-phase motor 400 connected in star connection via a capacitor Cn and a heating relay Ka.
  • the battery heating circuit further includes a first relay K1 , which is connected in series to one end of the first battery half-bridge circuit.
  • the battery heating circuit further includes a second relay K2 , which is connected in series to the other end of the first battery half-bridge circuit.
  • the first relay K1 and the second relay K2 are respectively the positive and negative relays of the battery pack 100.
  • the three-phase motor 400 is a star-connected three-phase motor.
  • the three-phase inverter 300 controls the three-phase current of the three-phase motor 400 during PWM modulation, so that the three-phase motor 400 generates the torque required by the vehicle.
  • PWM modulations will generate a high-frequency common-mode voltage at the neutral point of the star connection of the three-phase motor 400, and the main frequency component of the high-frequency common-mode voltage is the switching frequency of the three-phase inverter bridge (i.e., the three-phase inverter 300).
  • the three-phase motor is one of a permanent magnet synchronous motor, a brushless motor, and an asynchronous motor.
  • an embodiment of the present application provides an electric vehicle, which includes the transformer-based battery heating circuit shown in FIG. 1 a .
  • one end of the "primary circuit” i.e., primary coil + capacitor Cn + heating relay Ka
  • the neutral point of the motor which is one of the optional connection methods; in some embodiments, when there is a coupling capacitor in the battery heating circuit, one end of the primary circuit can be connected to the midpoint of the battery bridge in addition to being connected in the following manner.
  • Figure 1b is a circuit diagram of a second transformer-based battery heating circuit provided in an embodiment of the present application; as shown in Figure 1b, one end of the primary circuit is connected to the positive pole of the DC bus; optionally, one end of the primary circuit can be connected to the left or right end of K1, which is not limited here.
  • Figure 1c is a circuit diagram of a third transformer-based battery heating circuit provided in an embodiment of the present application; as shown in Figure 1c, one end of the primary circuit is connected to the negative pole of the DC bus; the principle is the same as above, and it can be connected to the left or right end of K2, which is not limited here.
  • Figure 1d is a circuit diagram of a fourth transformer-based battery heating circuit provided in an embodiment of the present application; as shown in Figure 1d, one end of the primary circuit is connected to an internal level point of the battery, and the internal level point of the battery can be any level point inside the battery, not necessarily a middle point.
  • the initial voltage on the capacitor Cn after power-on is generally zero, and during steady-state resonant heating, the voltage is approximately half of the DC bus voltage. Therefore, there is a transition process from the initial state to the steady state. During this process, there will be instantaneous large values of the voltage across the capacitor Cn and the primary current, requiring components to adopt larger specifications, which will lead to increased costs.
  • Figure 1f is a circuit diagram of the sixth transformer-based battery heating circuit provided in an embodiment of the present application; as shown in Figure 1f, the primary circuit is connected to the midpoint of the DC bus capacitor Cdc, and the DC bus capacitor Cdc is divided into two (capacitor Cdc1 and capacitor Cdc2), divided into two upper and lower parts with equal capacity; this connection method also has the advantage of a small transient process, but the DC bus capacitor Cdc becomes complex and the cost becomes high.
  • Figure 1g is a circuit diagram of the seventh transformer-based battery heating circuit provided in an embodiment of the present application; as shown in Figure 1g, on the basis of Figure 1f, the capacitor Cn is omitted, and the DC bus capacitor takes into account both the resonance and DC isolation functions; this connection method needs to take into account the normal DC bus voltage stabilization function of the DC bus capacitor Cdc, and also take into account the resonance and DC isolation function during heating.
  • FIG. 2 is a simplified model schematic diagram of a transformer-based battery heating circuit provided in an embodiment of the present application.
  • the circuit of FIG. 1 a can be simplified to the circuit model shown in FIG. 2 .
  • Ucom is the common-mode voltage of the three-phase motor 400 relative to the midpoint of the series battery pack 100
  • Ls is the common-mode inductance, including the common-mode inductance of the three-phase motor 400, the leakage inductance of the transformer 200 and the stray inductance of the cable
  • Lm is the excitation inductance of the transformer 200
  • R is the internal resistance of the entire battery pack 100.
  • Ucom is a square wave with a frequency equal to the switching frequency of the three-phase inverter bridge.
  • the Ucom waveform deviates from the square wave, but the frequency of the main component is still the switching frequency of the three-phase inverter bridge. Therefore, to simplify the analysis process, it can be assumed that Ucom is a sine wave with a frequency equal to the frequency of the three-phase inverter bridge.
  • the function ⁇ (f s f ac ,m) is an adjustment coefficient of the common mode voltage amplitude under different working conditions, and is a function of the motor current frequency f ac and the voltage utilization factor m of the three-phase inverter 300 .
  • the current flowing through the neutral point of the motor is:
  • the working mode of the battery heating circuit provided in the embodiment of the present application is as follows:
  • Ls is basically controlled by the common-mode inductance of the three-phase motor 400 and has a very small adjustable range, so the main adjustable quantities of the circuit are the capacity of Cn and the transformer ratio n.
  • n is selected according to the heating power P required by the battery, that is:
  • the transformer-based battery heating circuit provided in the example of the present application has a small common-mode current flowing through the motor during operation, and therefore has the following advantages: a) when heating the battery, components such as the three-phase motor 400 generate less heat; b) when heating the battery while driving, the impact on dynamic performance is small.
  • the battery heating circuit since the battery heating circuit operates in a resonant state, and because the transformer 200 transforms the internal resistance of the battery with a very small secondary resistance to a larger resistance on the primary side, the circuit has a high power factor, the current flowing through the neutral point of the motor is relatively small, and the motor generates less heat.
  • the current flowing through the midpoint since the current flowing through the midpoint is relatively small, and the current distributed to the three phases of the motor is only 1/3 of the midpoint current, only a small amount of current capacity is required from the three phases of the motor for heating the battery, and most of the remaining capacity can be used to drive the motor, so the output capacity of the motor in the driving state is less affected.
  • the battery voltage is 400V
  • the whole package ohmic internal resistance is 20m ⁇
  • the motor common mode inductance is 15uH
  • the inverter rated switching frequency is 10kHz
  • the rated current of each phase of the inverter is 300A effective value
  • the short-time peak current is 530A effective value
  • the target battery heating power is 20kW.
  • the neutral line current effective value is only 111A, after being evenly distributed to the three phases, each phase is only 37A, which is much less than the rated current and peak current.
  • the battery heating current reaches 1000A, which can make the battery obtain a heating power of 20kW.
  • the resonant frequency fr can be selected to be much higher than the normal switching frequency, such as 20kHz, and when heating is required, the switching frequency fs is increased to be close to fr.
  • the temperature is very low, allowing the inverter switching frequency to be increased, thereby increasing the inverter heating to heat the cold zone liquid.
  • connection mode of the transformer 200 and the battery pack 100 can be varied in many ways, and the number of the transformer 200 and the battery pack 100 can be multiple, and here only two transformer combinations are given as an example.
  • the transformer 200 can be connected in parallel or series on the primary side, in parallel or series on the secondary side, multiple secondary sides can each be a "battery full bridge", multiple battery full bridges can be connected in series or parallel, and so on, and there can be many combinations of this kind.
  • Figure 3 is a circuit diagram of a battery heating circuit of a battery stack provided in an embodiment of the present application
  • Figure 4 is a circuit diagram of a battery heating circuit of batteries connected in series provided in an embodiment of the present application; wherein, the battery pack 100 includes eight sub-batteries U1 ⁇ U8 and two transformers 200.
  • the heat generated by the battery can be used to heat the cold zone liquid, and then the crew cabin can be heated by a heat pump or other means.
  • injecting a high-frequency alternating current into a battery can be used to measure the internal impedance of the battery, thereby obtaining the temperature and health status of the battery.
  • FIG. 5 is a circuit diagram of the first single-battery half-bridge provided in an embodiment of the present application.
  • a group of capacitors can be used to implement a half-bridge, as shown in FIG5 , where capacitors Cb1 and Cb2 are used to form a half-bridge.
  • FIG. 6 is a circuit diagram of a second single-battery half-bridge provided in an embodiment of the present application.
  • the DC bus capacitor Cdc of the motor three-phase inverter may be split into two parts Cdc1 and Cdc2 to form a capacitor half-bridge.
  • Figure 7 is a circuit diagram of the primary circuit connected to one phase of the motor provided in an embodiment of the present application.
  • the other end of the primary circuit may not be connected to the neutral point of the motor, but directly connected to one phase of the motor, as shown in FIG7.
  • the principle is basically the same, except that the primary side of the transformer changes from the common mode voltage of the neutral point of the motor to the voltage of one of the three phases.
  • the three-phase inverter 300 includes a DC bus capacitor Cdc by default.
  • each embodiment can be integrated together to form an independent part, or each module can exist separately, or two or more modules can be integrated to form an independent part.

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Abstract

The present application relates to the technical field of power batteries, and provides a transformer-based battery heating circuit and an electric vehicle. In the battery heating circuit, a first sub-battery and a second sub-battery are connected in series to form a first battery half-bridge circuit, a third sub-battery and a fourth sub-battery are connected in series to form a second battery half-bridge circuit, and the first battery half-bridge circuit and the second battery half-bridge circuit are connected in parallel; a transformer is provided with a primary side and a secondary side; both ends of the secondary side are respectively connected to the midpoint of the first battery half-bridge circuit and the midpoint of the second battery half-bridge circuit; one end of the primary side is connected to one end point of a preset endpoint set; a three-phase motor is connected to the other end of the primary side and a three-phase inverter, respectively; the three-phase motor is connected to the transformer by means of a heating relay. According to the battery heating circuit, the technical effects that components generate less heat when a battery is heated, use in a traveling state can be allowed, and there is little impact on the dynamic properties of the motor can be achieved.

Description

一种基于变压器的电池加热电路及电动车辆A battery heating circuit based on transformer and electric vehicle
本申请要求于2022年10月26日提交中国专利局、申请号为202211317717.X、发明名称为“一种基于变压器的电池加热电路及电动车辆”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。This application claims priority to a Chinese patent application filed with the Chinese Patent Office on October 26, 2022, with application number 202211317717.X and invention name “A transformer-based battery heating circuit and electric vehicle”, the entire contents of which are incorporated by reference into this application.
技术领域Technical Field
本申请涉及动力电池技术领域，具体涉及一种基于变压器的电池加热电路及电动车辆。The present application relates to the technical field of power batteries, and in particular to a transformer-based battery heating circuit and an electric vehicle.
背景技术Background technique
目前，新能源汽车是指采用非常规的车用燃料作为动力来源(或使用常规的车用燃料、采用新型车载动力装置)，综合车辆的动力控制和驱动方面的先进技术，形成的技术原理先进、具有新技术、新结构的汽车。新能源汽车包括纯电动汽车、混合动力汽车等。At present, new energy vehicles refer to vehicles that use unconventional vehicle fuels as a power source (or use conventional vehicle fuels and adopt new vehicle power devices), and integrate advanced technologies in vehicle power control and drive to form vehicles with advanced technical principles, new technologies, and new structures. New energy vehicles include pure electric vehicles, hybrid vehicles, etc.
现有技术中，由于电动汽车的动力电池低温性能差，因此需要设法在低温下提高电池温度。当前常用的电池加热方法一般通过正温度系数电阻(PTC，Positive Temperature Coefficient)、电驱***产热等方法加热冷区液之后由冷区液加热电池，实现间接加热，或者通过电机控制器实现电机绕组的充放电，从而在电池里面产生交流电流，由电池内阻发热来加热电池，即电池内阻直接加热，或称电池自加热。当前常用的电池加热方法中，其间接加热方法效率很低，大量的热量无法有效传递给电池而耗散到了环境中；传热慢，热量需要通过冷区液、电池外部结构等输入电池，电池温升很慢；电池加热不均衡，靠近冷区液的电芯温升快；采用传统利用电机绕组直接加热方法时，加热电流频率偏低，直接加热的交流电流频率一般为2kHz左右，人耳十分敏感，噪声有很大；此类方法在车辆行驶状态下不易使用，容易造成转矩抖动或影响电机功率输出。In the prior art, since the low-temperature performance of the power battery of electric vehicles is poor, it is necessary to find a way to increase the battery temperature at low temperatures. The current commonly used battery heating method generally heats the cold zone liquid through positive temperature coefficient resistors (PTC, Positive Temperature Coefficient), electric drive system heat generation, etc., and then the cold zone liquid heats the battery to achieve indirect heating, or the motor winding is charged and discharged through the motor controller, thereby generating an AC current in the battery, and the battery is heated by the heat generated by the internal resistance of the battery, that is, direct heating of the internal resistance of the battery, or self-heating of the battery. Among the current commonly used battery heating methods, the indirect heating method is very inefficient, and a large amount of heat cannot be effectively transferred to the battery and is dissipated into the environment; the heat transfer is slow, and the heat needs to be input into the battery through the cold zone liquid, the external structure of the battery, etc., and the battery temperature rises very slowly; the battery heating is uneven, and the temperature of the battery cell close to the cold zone liquid rises quickly; when the traditional direct heating method using the motor winding is used, the heating current frequency is low, and the direct heating AC current frequency is generally about 2kHz, the human ear is very sensitive, and the noise is very large; this method is not easy to use when the vehicle is in motion, and it is easy to cause torque jitter or affect the motor power output.
发明内容Summary of the invention
本申请的目的在于提供一种基于变压器的电池加热电路及电动车辆，可以实现在加热电池时部件发热少、可行车状态加热和对电机动力性影响小的技术效果。The purpose of the present application is to provide a transformer-based battery heating circuit and electric vehicle, which can achieve the technical effects of less component heat generation when heating the battery, heating in driving state, and little impact on the motor power.
第一方面，本申请提供了一种基于变压器的电池加热电路，包括电池组、变压器、三相逆变器、加热继电器和三相电机；In a first aspect, the present application provides a transformer-based battery heating circuit, comprising a battery pack, a transformer, a three-phase inverter, a heating relay, and a three-phase motor;
所述电池组包括第一分电池、第二分电池、第三分电池和第四分电池，所述第一分电池和所述第二分电池串联为第一电池半桥电路，所述第三分电池和所述第四分电池串联为第二电池半桥电路，所述第一电池半桥电路和所述第二电池半桥电路并联；The battery pack comprises a first sub-battery, a second sub-battery, a third sub-battery and a fourth sub-battery, the first sub-battery and the second sub-battery are connected in series to form a first battery half-bridge circuit, the third sub-battery and the fourth sub-battery are connected in series to form a second battery half-bridge circuit, and the first battery half-bridge circuit and the second battery half-bridge circuit are connected in parallel;
所述变压器设置有原边和副边，所述副边的两端分别连接所述第一电池半桥电路的中点、所述第二电池半桥电路的中点，所述原边的一端连接预设端点集合的其中一个端点，所述预设端点集合包括所述第二电池半桥电路的中点、直流母线的正极、直流母线的负极、电池内部电平点、正负母线电容分压点、直流母线电容的中点、第二电池半桥；The transformer is provided with a primary side and a secondary side, the two ends of the secondary side are respectively connected to the midpoint of the first battery half-bridge circuit and the midpoint of the second battery half-bridge circuit, and one end of the primary side is connected to one of the endpoints of a preset endpoint set, and the preset endpoint set includes the midpoint of the second battery half-bridge circuit, the positive pole of the DC bus, the negative pole of the DC bus, the internal level point of the battery, the positive and negative bus capacitor voltage dividing point, the midpoint of the DC bus capacitor, and the second battery half-bridge;
所述三相电机分别与所述原边的另一端、所述三相逆变器连接，所述三相电机通过所述加热继电器连接所述变压器。The three-phase motor is connected to the other end of the primary side and the three-phase inverter respectively, and the three-phase motor is connected to the transformer through the heating relay.
在上述实现过程中，在需要进行电池加热的情况下，闭合加热继电器，无论车辆处于停车还是运行状态，通过三相逆变器的PWM调制对三相电机的三相电流进行控制，从而让三相电机产生相应的扭矩(在行车状态下，驱动车辆运行；在车辆静止状态下，输出零扭矩)；三相逆变器的PWM调制会在三相电机产生共模电压，该共模电压作用在变压器上，并在变压器的副边产生交变电流，该交变电流流经电池组中各个分电池的内阻，电池由此发热而升温，从而改善电池低温环境下的性能，提升车辆的续航能力和动力性；从而，该电池加热电路可以实现在加热电池时部件发热少、可行车状态加热和对电机动力性影响小的技术效果。In the above implementation process, when battery heating is required, the heating relay is closed, and no matter whether the vehicle is in a parked or running state, the three-phase current of the three-phase motor is controlled through the PWM modulation of the three-phase inverter, so that the three-phase motor generates corresponding torque (in the driving state, it drives the vehicle to run; when the vehicle is stationary, it outputs zero torque); the PWM modulation of the three-phase inverter will generate a common-mode voltage in the three-phase motor, and the common-mode voltage acts on the transformer and generates an alternating current on the secondary side of the transformer. The alternating current flows through the internal resistance of each sub-battery in the battery pack, and the battery is heated and heated, thereby improving the performance of the battery in a low-temperature environment and enhancing the vehicle's endurance and power; thus, the battery heating circuit can achieve the technical effects of less heating of components when heating the battery, heating in the driving state, and little impact on the motor power.
进一步地，所述三相逆变器包括三个功率开关管组件，所述功率开关管组件的一端连接所述第一电池半桥电路的一端，所述功率开关管组件的另一端连接所述第二电池半桥电路的另一端。Furthermore, the three-phase inverter includes three power switch tube assemblies, one end of the power switch tube assembly is connected to one end of the first battery half-bridge circuit, and the other end of the power switch tube assembly is connected to the other end of the second battery half-bridge circuit.
进一步地，所述功率开关管组件包括两个功率开关管，所述两个功率开关管串联。Furthermore, the power switch tube assembly includes two power switch tubes, and the two power switch tubes are connected in series.
进一步地，所述三相电机设置有三条电缆线，所述三条电缆线分别连接所述三个功率开关管组件。Furthermore, the three-phase motor is provided with three cables, and the three cables are respectively connected to the three power switch tube assemblies.
进一步地，所述电池加热电路还包括电容，所述电容和所述加热继电器串联。Furthermore, the battery heating circuit also includes a capacitor, and the capacitor and the heating relay are connected in series.
进一步地，所述电池加热电路还包括第一继电器，所述第一继电器串联在所述第一电池半桥电路的一端。Furthermore, the battery heating circuit also includes a first relay, which is connected in series to one end of the first battery half-bridge circuit.
进一步地，所述电池加热电路还包括第二继电器，所述第二继电器串联在所述第一电池半桥电路的另一端。Furthermore, the battery heating circuit also includes a second relay, which is connected in series to the other end of the first battery half-bridge circuit.
在上述实现过程中，第一继电器、第二继电器分别是电池组的正、负继电器。In the above implementation process, the first relay and the second relay are respectively the positive and negative relays of the battery pack.
进一步地，所述三相电机为星形连接的三相电机。Furthermore, the three-phase motor is a star-connected three-phase motor.
进一步地，所述三相电机为永磁同步电机、无刷电机、异步电机中的一种。Furthermore, the three-phase motor is one of a permanent magnet synchronous motor, a brushless motor, and an asynchronous motor.
第二方面，本申请提供了一种电动车辆，所述电动车辆包括第一方面任一项所述的基于变压器的电池加热电路。In a second aspect, the present application provides an electric vehicle, comprising the transformer-based battery heating circuit as described in any one of the first aspects.
本申请公开的其他特征和优点将在随后的说明书中阐述，或者，部分特征和优点可以从说明书推知或毫无疑义地确定，或者通过实施本申请公开的上述技术即可得知。Other features and advantages disclosed in the present application will be described in the following description, or some features and advantages can be inferred or determined without doubt from the description, or can be learned by implementing the above-mentioned technology disclosed in the present application.
为使本申请的上述目的、特征和优点能更明显易懂，下文特举较佳实施例，并配合所附附图，作详细说明如下。In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings.
附图说明BRIEF DESCRIPTION OF THE DRAWINGS
为了更清楚地说明本申请实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
图1a为本申请实施例提供的第一种基于变压器的电池加热电路的电路示意图。FIG. 1 a is a circuit diagram of a first transformer-based battery heating circuit provided in an embodiment of the present application.
图1b为本申请实施例提供的第二种基于变压器的电池加热电路的电路示意图。FIG1 b is a circuit diagram of a second transformer-based battery heating circuit provided in an embodiment of the present application.
图1c为本申请实施例提供的第三种基于变压器的电池加热电路的电路示意图。FIG. 1c is a circuit diagram of a third transformer-based battery heating circuit provided in an embodiment of the present application.
图1d为本申请实施例提供的第四种基于变压器的电池加热电路的电路示意 图。FIG1d is a circuit diagram of a fourth transformer-based battery heating circuit provided in an embodiment of the present application.
图1e为本申请实施例提供的第五种基于变压器的电池加热电路的电路示意图。FIG. 1e is a circuit diagram of a fifth transformer-based battery heating circuit provided in an embodiment of the present application.
图1f为本申请实施例提供的第六种基于变压器的电池加热电路的电路示意图。FIG. 1f is a circuit diagram of a sixth transformer-based battery heating circuit provided in an embodiment of the present application.
图1g为本申请实施例提供的第七种基于变压器的电池加热电路的电路示意图。FIG1g is a circuit diagram of a seventh transformer-based battery heating circuit provided in an embodiment of the present application.
图2为本申请实施例提供的基于变压器的电池加热电路的简化模型示意图。FIG. 2 is a simplified model schematic diagram of a transformer-based battery heating circuit provided in an embodiment of the present application.
图3为本申请实施例提供的电池堆叠的电池加热电路的电路示意图。FIG3 is a circuit diagram of a battery heating circuit of a battery stack provided in an embodiment of the present application.
图4为本申请实施例提供的电池串联的电池加热电路的电路示意图。FIG. 4 is a circuit diagram of a battery heating circuit with batteries connected in series provided in an embodiment of the present application.
图5为本申请实施例提供的第一种单电池半桥的电路示意图。FIG5 is a circuit diagram of a first single-cell half-bridge provided in an embodiment of the present application.
图6为本申请实施例提供的第二种单电池半桥的电路示意图。FIG6 is a circuit diagram of a second single-battery half-bridge provided in an embodiment of the present application.
图7为本申请实施例提供的原边电路连接电机其中一相的电路示意图。FIG. 7 is a schematic diagram of a circuit in which a primary circuit is connected to one phase of a motor according to an embodiment of the present application.
具体实施方式Detailed ways
为了使本技术领域的人员更好地理解本申请方案，下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本申请一部分的实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都应当属于本申请保护的范围。In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this application.
在本申请的描述中，需要说明的是，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或一体地连接；可以是机械连接，也可以是电连接或可以相互通讯；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通或两个元件的相互作用关系。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本申请中的具体含义。In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.
在本申请的描述中，“第一”、“第二”等字样仅用于区别不同对象，并不对数量和执行次序进行限定，并且“第一”、“第二”等字样也并不限定一定不同。此外，术语“包括”和“具有”以及它们的任何变形，意图在于覆盖不排他的包含。同时，应注意到：相似的标号和字母在下面的附图中表示类似项，因此， 一旦某一项在一个附图中被定义，则在随后的附图中不需要对其进行进一步定义和解释。In the description of the present application, the words "first", "second", etc. are only used to distinguish different objects, and do not limit the quantity and execution order, and the words "first", "second", etc. do not necessarily limit the difference. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. At the same time, it should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.
本申请实施例提供了一种基于变压器的电池加热电路及电动车辆，可以应用于电池加热过程中；在需要进行电池加热的情况下，闭合加热继电器，无论车辆处于停车还是运行状态，通过三相逆变器的PWM调制对三相电机的三相电流进行控制，从而让三相电机产生相应的扭矩(在行车状态下，驱动车辆运行；在车辆静止状态下，输出零扭矩)；三相逆变器的PWM调制会在三相电机产生共模电压，该共模电压作用在变压器上，并在变压器的副边产生交变电流，该交变电流流经电池组中各个分电池的内阻，电池由此发热而升温，从而改善电池低温环境下的性能，提升车辆的续航能力和动力性；从而，该电池加热电路可以实现在加热电池时部件发热少、可行车状态加热和对电机动力性影响小的技术效果。The embodiment of the present application provides a transformer-based battery heating circuit and an electric vehicle, which can be used in the battery heating process; when battery heating is required, the heating relay is closed, and no matter whether the vehicle is in a parked or running state, the three-phase current of the three-phase motor is controlled through the PWM modulation of the three-phase inverter, so that the three-phase motor generates corresponding torque (in the driving state, drives the vehicle to run; when the vehicle is stationary, outputs zero torque); the PWM modulation of the three-phase inverter will generate a common-mode voltage in the three-phase motor, and the common-mode voltage acts on the transformer and generates an alternating current on the secondary side of the transformer. The alternating current flows through the internal resistance of each sub-battery in the battery pack, and the battery is heated and heated, thereby improving the battery performance in a low-temperature environment and enhancing the vehicle's endurance and power; thus, the battery heating circuit can achieve the technical effects of less component heat generation when heating the battery, heating in the driving state, and little impact on the motor power.
请参见图1a，图1a为本申请实施例提供的第一种基于变压器的电池加热电路的电路示意图，该基于变压器的电池加热电路包括电池组100、变压器200、三相逆变器300、加热继电器Ka和三相电机400。Please refer to Figure 1a, which is a circuit diagram of a first transformer-based battery heating circuit provided in an embodiment of the present application. The transformer-based battery heating circuit includes a battery pack 100, a transformer 200, a three-phase inverter 300, a heating relay Ka and a three-phase motor 400.
示例性地，电池组100包括第一分电池U1、第二分电池U2、第三分电池U3和第四分电池U4，第一分电池U1和第二分电池U2串联为第一电池半桥电路，第三分电池U3和第四分电池U4串联为第二电池半桥电路，第一电池半桥电路和第二电池半桥电路并联。Exemplarily, the battery pack 100 includes a first sub-battery U1, a second sub-battery U2, a third sub-battery U3 and a fourth sub-battery U4, the first sub-battery U1 and the second sub-battery U2 are connected in series to form a first battery half-bridge circuit, the third sub-battery U3 and the fourth sub-battery U4 are connected in series to form a second battery half-bridge circuit, and the first battery half-bridge circuit and the second battery half-bridge circuit are connected in parallel.
在一些实施方式中，第一分电池U1和第二分电池U2对称，第三分电池U3和第四分电池U4对称；第一分电池U1和第三分电池U3的电压相同、第二分电池U2和第四分电池U4的电压相同。第一分电池U1和第二分电池U2、第三分电池U3和第四分电池U4，分别串联形成两个“半桥”电路，然后两个“半桥”电路并联，形成一个“全桥”。In some embodiments, the first sub-battery U1 and the second sub-battery U2 are symmetrical, and the third sub-battery U3 and the fourth sub-battery U4 are symmetrical; the voltages of the first sub-battery U1 and the third sub-battery U3 are the same, and the voltages of the second sub-battery U2 and the fourth sub-battery U4 are the same. The first sub-battery U1 and the second sub-battery U2, the third sub-battery U3 and the fourth sub-battery U4 are connected in series to form two "half-bridge" circuits, and then the two "half-bridge" circuits are connected in parallel to form a "full bridge".
可选地，第一分电池U1和第三分电池U3的容量有差异、第二分电池U2和第四分电池U4的容量有差异，以保持温升一致。Optionally, the first sub-battery U1 and the third sub-battery U3 have different capacities, and the second sub-battery U2 and the fourth sub-battery U4 have different capacities, so as to keep the temperature rise consistent.
示例性地，变压器200设置有原边和副边，副边的两端分别连接第一电池半桥电路的中点、第二电池半桥电路的中点，原边的一端连接预设端点集合的其中一个端点，所述预设端点集合包括所述第二电池半桥电路的中点、直流母线的正极、直流母线的负极、电池内部电平点、正负母线电容分压点、直流母线电容 的中点第二电池半桥。Exemplarily, the transformer 200 is provided with a primary side and a secondary side, the two ends of the secondary side are respectively connected to the midpoint of the first battery half-bridge circuit and the midpoint of the second battery half-bridge circuit, and one end of the primary side is connected to one of the endpoints of a preset endpoint set, and the preset endpoint set includes the midpoint of the second battery half-bridge circuit, the positive pole of the DC bus, the negative pole of the DC bus, the internal level point of the battery, the positive and negative bus capacitor voltage divider point, and the midpoint of the DC bus capacitor of the second battery half-bridge.
示例性地，图1a所示的实施例中，原边的一端连接第二电池半桥电路的中点；在第一电池半桥电路的中点、第二电池半桥电路的中点之间用一个变压器200的副边连接；变压器200的原边一端也连接第二电池半桥电路的中点，即该端也因此连接了副边的异名端。变压器的变比，根据电池的电压、电池的内阻、电池的加热功率需求进行设计。For example, in the embodiment shown in FIG1a, one end of the primary side is connected to the midpoint of the second battery half-bridge circuit; a secondary side of a transformer 200 is connected between the midpoint of the first battery half-bridge circuit and the midpoint of the second battery half-bridge circuit; one end of the primary side of the transformer 200 is also connected to the midpoint of the second battery half-bridge circuit, that is, this end is also connected to the opposite end of the secondary side. The transformer ratio is designed according to the battery voltage, the battery internal resistance, and the battery heating power requirement.
示例性地，变压器(Transformer)是利用电磁感应的原理来改变交流电压的装置，主要构件是初级线圈、次级线圈和铁芯(磁芯)。主要功能有：电压变换、电流变换、阻抗变换、隔离等。按用途可以分为：电力变压器和特殊变压器(电炉变、整流变、工频试验变压器、调压器、矿用变、音频变压器、中频变压器、高频变压器、冲击变压器、仪用变压器、电子变压器、电抗器、互感器等)。其中，变压器200的原边是指电压的输入侧，副边是指电压经变压器转换后电压的输出侧。Exemplarily, a transformer is a device that uses the principle of electromagnetic induction to change the AC voltage. Its main components are the primary coil, the secondary coil and the iron core (magnetic core). The main functions are: voltage conversion, current conversion, impedance conversion, isolation, etc. According to the purpose, it can be divided into: power transformers and special transformers (furnace transformers, rectifier transformers, industrial frequency test transformers, voltage regulators, mining transformers, audio transformers, medium frequency transformers, high frequency transformers, impact transformers, instrument transformers, electronic transformers, reactors, mutual inductors, etc.). Among them, the primary side of the transformer 200 refers to the input side of the voltage, and the secondary side refers to the output side of the voltage after the voltage is converted by the transformer.
示例性地，三相电机400分别与变压器200原边的另一端、三相逆变器300连接，三相电机400通过加热继电器Ka连接变压器200。Exemplarily, the three-phase motor 400 is connected to the other end of the primary side of the transformer 200 and the three-phase inverter 300 respectively, and the three-phase motor 400 is connected to the transformer 200 via a heating relay Ka.
示例性地，通过加热继电器Ka，一方面可以在车辆故障状态下切断电路进行保护，另一方面可以在电池没有加热需求的时候切断电路，停止电池加热。For example, by heating the relay Ka, on the one hand, the circuit can be cut off for protection when the vehicle fails, and on the other hand, the circuit can be cut off to stop battery heating when there is no need to heat the battery.
示例性地，在需要进行电池加热的情况下，闭合加热继电器Ka，无论车辆处于停车还是运行状态，通过三相逆变器300的PWM调制对三相电机的三相电流进行控制，从而让三相电机400产生相应的扭矩(在行车状态下，驱动车辆运行；在车辆静止状态下，输出零扭矩)；三相逆变器300的PWM调制会在三相电机400产生共模电压，该共模电压作用在变压器上，并在变压器的副边产生交变电流，该交变电流流经电池组100中各个分电池的内阻，电池由此发热而升温，从而改善电池低温环境下的性能，提升车辆的续航能力和动力性；从而，该电池加热电路可以实现在加热电池时部件发热少、可行车状态加热和对电机动力性影响小的技术效果。Exemplarily, when battery heating is required, the heating relay Ka is closed, and the three-phase current of the three-phase motor is controlled by the PWM modulation of the three-phase inverter 300 regardless of whether the vehicle is in the parked or running state, so that the three-phase motor 400 generates corresponding torque (in the driving state, drives the vehicle to run; when the vehicle is stationary, outputs zero torque); the PWM modulation of the three-phase inverter 300 will generate a common-mode voltage in the three-phase motor 400, and the common-mode voltage acts on the transformer and generates an alternating current on the secondary side of the transformer. The alternating current flows through the internal resistance of each sub-battery in the battery pack 100, and the battery generates heat and heats up, thereby improving the battery performance in a low-temperature environment and enhancing the vehicle's endurance and power; thus, the battery heating circuit can achieve the technical effects of less component heat generation when heating the battery, heating in the driving state, and little impact on the motor power.
示例性地，脉冲宽度调制(PWM，Pulse width modulation)是一种模拟控制方式，根据相应载荷的变化来调制晶体管基极或场效应管栅极的偏置，来实现晶体管或场效应管导通时间的改变，从而实现开关稳压电源输出的改变。这种方式能使电源的输出电压在工作条件变化时保持恒定，是利用微处理器的数字信号 对模拟电路进行控制的一种非常有效的技术。广泛应用在从测量、通信到功率控制与变换的许多领域中。For example, pulse width modulation (PWM) is an analog control method that modulates the bias of the transistor base or the gate of the field effect tube according to the change of the corresponding load to achieve the change of the conduction time of the transistor or the field effect tube, thereby achieving the change of the output of the switching regulated power supply. This method can keep the output voltage of the power supply constant when the working conditions change. It is a very effective technology for controlling analog circuits using digital signals of microprocessors. It is widely used in many fields from measurement, communication to power control and conversion.
在一些实施方式中，三相逆变器300可以采用SPWM(正弦PWM调制)、SVPWM(空间矢量PWM调制)或其他调制方法，如DPWM(非连续PWM调制)，进行控制；需要注意的是，此处三相逆变器300的PWM调制方式，仅作为示例而非限定。In some embodiments, the three-phase inverter 300 can be controlled using SPWM (sinusoidal PWM modulation), SVPWM (space vector PWM modulation) or other modulation methods, such as DPWM (discontinuous PWM modulation); it should be noted that the PWM modulation method of the three-phase inverter 300 here is only an example and not a limitation.
示例性地，三相逆变器300包括三个功率开关管组件，功率开关管组件的一端连接第一电池半桥电路的一端，功率开关管组件的另一端连接第二电池半桥电路的另一端。Exemplarily, the three-phase inverter 300 includes three power switch tube assemblies, one end of the power switch tube assembly is connected to one end of the first battery half-bridge circuit, and the other end of the power switch tube assembly is connected to the other end of the second battery half-bridge circuit.
示例性地，功率开关管组件包括两个功率开关管，两个功率开关管串联。Exemplarily, the power switch tube assembly includes two power switch tubes, and the two power switch tubes are connected in series.
示例性地，三个功率开关管组件包括6个功率开关管Q1～Q6，即驱动三相电机400运转的三相逆变器300的6个半导体功率开关管。Exemplarily, the three power switch tube assemblies include six power switch tubes Q1 to Q6 , namely, six semiconductor power switch tubes of the three-phase inverter 300 that drive the three-phase motor 400 to operate.
在一些实施方式中，功率开关管组件的功率开关管可以是场效应管、绝缘栅双极型晶体管等半导体功率开关器件。In some embodiments, the power switch tube of the power switch tube assembly may be a semiconductor power switch device such as a field effect tube, an insulated gate bipolar transistor, etc.
示例性地，三相电机设置有三条电缆线，三条电缆线分别连接三个功率开关管组件。Exemplarily, the three-phase motor is provided with three cables, and the three cables are respectively connected to three power switch tube assemblies.
示例性地，电池加热电路还包括电容，电容和加热继电器串联。Exemplarily, the battery heating circuit further includes a capacitor, and the capacitor and the heating relay are connected in series.
示例性地，变压器200通过一个电容Cn、加热继电器Ka连接到三相电机400。电容Cn的作用一方面是隔离直流，防止变压器200偏磁饱和，另一方面是和三相电机400的共模电感、变压器200的漏感谐振。Exemplarily, the transformer 200 is connected to the three-phase motor 400 via a capacitor Cn and a heating relay Ka. The capacitor Cn is used to isolate DC and prevent the transformer 200 from being magnetically saturated, and to resonate with the common mode inductance of the three-phase motor 400 and the leakage inductance of the transformer 200.
需要注意的是，变压器原边的电路连接时，因为原边线圈、电容Cn(即谐振电容)、加热继电器Ka都是串联的，因此他们的相对顺序并不影响电路，原边线圈、电容Cn、加热继电器Ka串联时所有排序的电路都是等效的。It should be noted that when the primary circuit of the transformer is connected, because the primary coil, capacitor Cn (i.e., resonant capacitor), and heating relay Ka are all connected in series, their relative order does not affect the circuit. When the primary coil, capacitor Cn, and heating relay Ka are connected in series, all circuits of different arrangements are equivalent.
在一些实施方式中，变压器200通过一个电容Cn、加热继电器Ka连接到三相电机400星形连接的中性点。In some embodiments, the transformer 200 is connected to the neutral point of the three-phase motor 400 connected in star connection via a capacitor Cn and a heating relay Ka.
示例性地，电池加热电路还包括第一继电器K1，第一继电器K1串联在第一电池半桥电路的一端。Exemplarily, the battery heating circuit further includes a first relay K1 , which is connected in series to one end of the first battery half-bridge circuit.
示例性地，电池加热电路还包括第二继电器K2，第二继电器K2串联在第一电池半桥电路的另一端。Exemplarily, the battery heating circuit further includes a second relay K2 , which is connected in series to the other end of the first battery half-bridge circuit.
示例性地，第一继电器K1、第二继电器K2分别是电池组100的正、负继 电器。Exemplarily, the first relay K1 and the second relay K2 are respectively the positive and negative relays of the battery pack 100.
示例性地，三相电机400为星形连接的三相电机。Exemplarily, the three-phase motor 400 is a star-connected three-phase motor.
示例性地，三相逆变器300在进行PWM调制的过程中，对三相电机400的三相电流进行控制，从而让三相电机400产生车辆所需的扭矩。这些PWM调制会在三相电机400星形连接的中性点产生高频共模电压，其高频共模电压的主要频率分量为三相逆变桥(即三相逆变器300)的开关频率。For example, the three-phase inverter 300 controls the three-phase current of the three-phase motor 400 during PWM modulation, so that the three-phase motor 400 generates the torque required by the vehicle. These PWM modulations will generate a high-frequency common-mode voltage at the neutral point of the star connection of the three-phase motor 400, and the main frequency component of the high-frequency common-mode voltage is the switching frequency of the three-phase inverter bridge (i.e., the three-phase inverter 300).
示例性地，三相电机为永磁同步电机、无刷电机、异步电机中的一种。Exemplarily, the three-phase motor is one of a permanent magnet synchronous motor, a brushless motor, and an asynchronous motor.
示例性地，本申请实施例提供了一种电动车辆，电动车辆包括图1a所示的基于变压器的电池加热电路。Exemplarily, an embodiment of the present application provides an electric vehicle, which includes the transformer-based battery heating circuit shown in FIG. 1 a .
示例性地，本申请实施例提供的电池加热电路中的“原边电路”(即原边线圈+电容Cn+加热继电器Ka)的一端连接电机的中性点，为其中一种可选的连接方式；在一些实施方式中，在电池加热电路存在耦合电容的情况下，原边电路的一端除了可以连接电池桥的中点外，还可以按照如下方式连接。Exemplarily, one end of the "primary circuit" (i.e., primary coil + capacitor Cn + heating relay Ka) in the battery heating circuit provided in the embodiment of the present application is connected to the neutral point of the motor, which is one of the optional connection methods; in some embodiments, when there is a coupling capacitor in the battery heating circuit, one end of the primary circuit can be connected to the midpoint of the battery bridge in addition to being connected in the following manner.
请参见图1b，图1b为本申请实施例提供的第二种基于变压器的电池加热电路的电路示意图；图1b所示，原边电路的一端连接直流母线的正极；可选地，原边电路的一端可以连接在K1的左端或者右端，此处不做限定。Please refer to Figure 1b, which is a circuit diagram of a second transformer-based battery heating circuit provided in an embodiment of the present application; as shown in Figure 1b, one end of the primary circuit is connected to the positive pole of the DC bus; optionally, one end of the primary circuit can be connected to the left or right end of K1, which is not limited here.
请参见图1c，图1c为本申请实施例提供的第三种基于变压器的电池加热电路的电路示意图；图1c所示，原边电路的一端连接直流母线的负极；原理同上，可以连接在K2的左端或者右端，此处不做限定。Please refer to Figure 1c, which is a circuit diagram of a third transformer-based battery heating circuit provided in an embodiment of the present application; as shown in Figure 1c, one end of the primary circuit is connected to the negative pole of the DC bus; the principle is the same as above, and it can be connected to the left or right end of K2, which is not limited here.
请参见图1d，图1d为本申请实施例提供的第四种基于变压器的电池加热电路的电路示意图；图1d所示，原边电路的一端连接电池内部电平点，该电池内部电平点可以是电池内部的任意电平点，不一定是中间点。Please refer to Figure 1d, which is a circuit diagram of a fourth transformer-based battery heating circuit provided in an embodiment of the present application; as shown in Figure 1d, one end of the primary circuit is connected to an internal level point of the battery, and the internal level point of the battery can be any level point inside the battery, not necessarily a middle point.
请参见图1e，图1e为本申请实施例提供的第五种基于变压器的电池加热电路的电路示意图；图1e所示，电容Cn变成“三端电容”(分为电容Cn1、电容Cn2)，其两端跨接在正负母线上(即正负母线电容分压)，中心点连接原边电路(此时原边电路＝加热继电器Ka+原边线圈)。Please refer to Figure 1e, which is a circuit diagram of the fifth transformer-based battery heating circuit provided in an embodiment of the present application; as shown in Figure 1e, the capacitor Cn becomes a "three-terminal capacitor" (divided into capacitor Cn1 and capacitor Cn2), with its two ends bridged across the positive and negative bus bars (i.e., the positive and negative bus bar capacitors divide the voltage), and the center point is connected to the primary circuit (at this time, the primary circuit = heating relay Ka + primary coil).
示例性地，图1e所示的连接方式相比图1a至图1d所示的连接方式，其优点为：电路上电之后(K1、K2闭合)，电容Cn1和电容Cn2的初始电压和稳定工作的时候的电压基本相差无几，当电路开始加热的时候，电路从开始工作到达到稳态谐振的过程中，电容Cn1、电容Cn2的电压、原边流过的电流等暂态谐 振很少，有利于减少变压器、电容Cn(＝Cn1+Cn2)等元器件上的暂态最高电压、最大电流，从而有利于降低对这些元器件的规格要求，实现成本的降低。Exemplarily, the connection mode shown in FIG. 1e has the following advantages compared to the connection modes shown in FIG. 1a to FIG. 1d: after the circuit is powered on (K1 and K2 are closed), the initial voltage of capacitor Cn1 and capacitor Cn2 is basically the same as the voltage during stable operation. When the circuit starts to heat up, there is little transient resonance such as the voltage of capacitor Cn1 and capacitor Cn2 and the current flowing through the primary side during the process from the start of operation to the steady-state resonance of the circuit. This is beneficial to reduce the transient maximum voltage and maximum current on components such as the transformer and capacitor Cn (=Cn1+Cn2), thereby helping to reduce the specification requirements for these components and achieve cost reduction.
示例性地，图1a至图1d所示的连接方式，上电之后电容Cn上的初始电压一般为零，而稳态谐振加热的时候，电压约为一半的直流母线电压，因此从初始状态到稳态会经历一个过渡过程，在这个过程中会存在Cn电容两端电压、原边电流的瞬间较大值，要求元器件采用较大的规格，这会导致成本的增加。Exemplarily, in the connection methods shown in Figures 1a to 1d, the initial voltage on the capacitor Cn after power-on is generally zero, and during steady-state resonant heating, the voltage is approximately half of the DC bus voltage. Therefore, there is a transition process from the initial state to the steady state. During this process, there will be instantaneous large values of the voltage across the capacitor Cn and the primary current, requiring components to adopt larger specifications, which will lead to increased costs.
请参见图1f，图1f为本申请实施例提供的第六种基于变压器的电池加热电路的电路示意图；图1f所示，原边电路接直流母线电容Cdc的中点，直流母线电容Cdc一分为二(电容Cdc1和电容Cdc2)，分成容量相等的上下两部分；该连接方式也具有暂态过程小的优点，但是直流母线电容Cdc变得复杂成本变高。Please refer to Figure 1f, which is a circuit diagram of the sixth transformer-based battery heating circuit provided in an embodiment of the present application; as shown in Figure 1f, the primary circuit is connected to the midpoint of the DC bus capacitor Cdc, and the DC bus capacitor Cdc is divided into two (capacitor Cdc1 and capacitor Cdc2), divided into two upper and lower parts with equal capacity; this connection method also has the advantage of a small transient process, but the DC bus capacitor Cdc becomes complex and the cost becomes high.
请参见图1g，图1g为本申请实施例提供的第七种基于变压器的电池加热电路的电路示意图；图1g所示，在图1f的基础上，省去电容Cn，由直流母线电容兼顾谐振、隔直作用；该连接方式，需要兼顾直流母线电容Cdc正常的直流母线稳压作用，又要兼顾加热时候的谐振隔直作用。Please refer to Figure 1g, which is a circuit diagram of the seventh transformer-based battery heating circuit provided in an embodiment of the present application; as shown in Figure 1g, on the basis of Figure 1f, the capacitor Cn is omitted, and the DC bus capacitor takes into account both the resonance and DC isolation functions; this connection method needs to take into account the normal DC bus voltage stabilization function of the DC bus capacitor Cdc, and also take into account the resonance and DC isolation function during heating.
请参见图2，图2为本申请实施例提供的基于变压器的电池加热电路的简化模型示意图。Please refer to FIG. 2 , which is a simplified model schematic diagram of a transformer-based battery heating circuit provided in an embodiment of the present application.
示例性地，若变压器200变比足够大，使得变压器200的原边电流相比副边电流可以忽略，则图1a的电路可以简化为图2所示的电路模型。Exemplarily, if the transformation ratio of the transformer 200 is large enough so that the primary current of the transformer 200 can be ignored compared with the secondary current, the circuit of FIG. 1 a can be simplified to the circuit model shown in FIG. 2 .
示例性地，Ucom为三相电机400相对串联电池组100中点的共模电压；Ls为共模电感，包括三相电机400的共模电感、变压器200的漏感和电缆线的杂散电感；Lm为变压器200的励磁电感；R为电池组100的整包内阻。Exemplarily, Ucom is the common-mode voltage of the three-phase motor 400 relative to the midpoint of the series battery pack 100; Ls is the common-mode inductance, including the common-mode inductance of the three-phase motor 400, the leakage inductance of the transformer 200 and the stray inductance of the cable; Lm is the excitation inductance of the transformer 200; and R is the internal resistance of the entire battery pack 100.
示例性地，在车辆停止的时候，无论采用SPWM调制还是SVPWM调制，Ucom都是频率等于三相逆变桥开关频率的方波。在车辆运行的情况下，Ucom波形偏离方波，但是主要的分量的频率仍然是三相逆变桥的开关频率。因此，为简化分析过程，可以假设Ucom为一个频率等于三相逆变桥频率的正弦波。For example, when the vehicle is stopped, regardless of whether SPWM modulation or SVPWM modulation is used, Ucom is a square wave with a frequency equal to the switching frequency of the three-phase inverter bridge. When the vehicle is running, the Ucom waveform deviates from the square wave, but the frequency of the main component is still the switching frequency of the three-phase inverter bridge. Therefore, to simplify the analysis process, it can be assumed that Ucom is a sine wave with a frequency equal to the frequency of the three-phase inverter bridge.
Figure PCTCN2023070779-appb-000001
Figure PCTCN2023070779-appb-000001
其中，函数η(f sf ac,m)为共模电压幅值在不同工况下的调整系数，它是电机电流频率f ac和三相逆变器300的电压利用率m的函数。 The function η(f s f ac ,m) is an adjustment coefficient of the common mode voltage amplitude under different working conditions, and is a function of the motor current frequency f ac and the voltage utilization factor m of the three-phase inverter 300 .
当车辆停止、三相电机400静止时，采用SVPWM调制或者SPWM调制的 情况下，此时有：When the vehicle stops and the three-phase motor 400 is stationary, when SVPWM modulation or SPWM modulation is adopted, the following conditions are met:
Figure PCTCN2023070779-appb-000002
Figure PCTCN2023070779-appb-000002
其有效值为：Valid values are:
Figure PCTCN2023070779-appb-000003
Figure PCTCN2023070779-appb-000003
根据图2中所述电路，假设Lm远大于Ls而可以忽略，则可以计算得到内阻R上的电流有效值为：According to the circuit in Figure 2, assuming that Lm is much larger than Ls and can be ignored, the effective value of the current on the internal resistance R can be calculated as:
Figure PCTCN2023070779-appb-000004
Figure PCTCN2023070779-appb-000004
其中，变压器200的变比n＝Np/Ns，fr为Ls和Cn的谐振频率，Zr为谐振阻抗，它们和Ls、Cn的关系如下：Wherein, the transformation ratio of the transformer 200 is n=Np/Ns, fr is the resonant frequency of Ls and Cn, and Zr is the resonant impedance, and their relationship with Ls and Cn is as follows:
Figure PCTCN2023070779-appb-000005
Figure PCTCN2023070779-appb-000005
Figure PCTCN2023070779-appb-000006
Figure PCTCN2023070779-appb-000006
流过电机中性点的电流为：The current flowing through the neutral point of the motor is:
Figure PCTCN2023070779-appb-000007
Figure PCTCN2023070779-appb-000007
由式4、式7可得：From formula 4 and formula 7, we can get:
Figure PCTCN2023070779-appb-000008
Figure PCTCN2023070779-appb-000008
示例性地，本申请实施例提供的电池加热电路的工作模式示例如下：Exemplarily, the working mode of the battery heating circuit provided in the embodiment of the present application is as follows:
Ls基本由三相电机400的共模电感控制，可调范围很小，因此电路的主要可调量是Cn的容量和变压器变比n。Ls is basically controlled by the common-mode inductance of the three-phase motor 400 and has a very small adjustable range, so the main adjustable quantities of the circuit are the capacity of Cn and the transformer ratio n.
选择Cn使得fs≈fr，则有：Choose Cn so that fs≈fr, then:
Figure PCTCN2023070779-appb-000009
Figure PCTCN2023070779-appb-000009
Figure PCTCN2023070779-appb-000010
Figure PCTCN2023070779-appb-000010
在此基础上，根据电池所需加热功率P选择n，即：On this basis, n is selected according to the heating power P required by the battery, that is:
Figure PCTCN2023070779-appb-000011
Figure PCTCN2023070779-appb-000011
此时又有：At this time there are:
Figure PCTCN2023070779-appb-000012
Figure PCTCN2023070779-appb-000012
在此模式下，由式4可知，通过调节开关频率fs，可以在一定范围内对加热功率进行调节。当完全不需要电池加热的时候，则切换加热继电器Ka。In this mode, it can be seen from Formula 4 that by adjusting the switching frequency fs, the heating power can be adjusted within a certain range. When battery heating is not required at all, the heating relay Ka is switched.
本申请示例提供的基于变压器的电池加热电路，工作时流过电机的共模电流小，因此具备如下优点：a)加热电池时，三相电机400等部件发热少；b)在行车状态下加热电池时，对动力性的影响较小。The transformer-based battery heating circuit provided in the example of the present application has a small common-mode current flowing through the motor during operation, and therefore has the following advantages: a) when heating the battery, components such as the three-phase motor 400 generate less heat; b) when heating the battery while driving, the impact on dynamic performance is small.
示例性地，由于电池加热电路工作在谐振状态，又因为通过变压器200变换，将副边阻值很小的电池内阻变换到了原边成为较大的电阻，因此该电路功率因数高，流过电机中性点的电流比较小，电机发热较小。在行程状态下加热时，由于流过中点的电流比较小，分配在电机三相的电流又只有中点电流的1/3，因此只需要电机三相留出少许电流能力用于加热电池，剩余大部分能力都可以用于驱动电机，因此对行车状态下的电机输出能力影响小。For example, since the battery heating circuit operates in a resonant state, and because the transformer 200 transforms the internal resistance of the battery with a very small secondary resistance to a larger resistance on the primary side, the circuit has a high power factor, the current flowing through the neutral point of the motor is relatively small, and the motor generates less heat. When heating in the travel state, since the current flowing through the midpoint is relatively small, and the current distributed to the three phases of the motor is only 1/3 of the midpoint current, only a small amount of current capacity is required from the three phases of the motor for heating the battery, and most of the remaining capacity can be used to drive the motor, so the output capacity of the motor in the driving state is less affected.
在一些实施场景中，对于某电驱***，电池电压为400V，整包欧姆内阻为20mΩ，电机共模电感为15uH，逆变器额定开关频率为10kHz，逆变器三相每一相额定电流为300A有效值，短时峰值电流为530A有效值，目标电池加热功率为20kW。则选择变压器变比为9，Cn＝16.9uF，此时中线电流有效值仅为111A，平均分配给三相之后每相只有37A，远小于额定电流和峰值电流。然而此时变压器的副边，电池的加热电流达到了1000A，可使电池得到了20kW的加热功率。In some implementation scenarios, for a certain electric drive system, the battery voltage is 400V, the whole package ohmic internal resistance is 20mΩ, the motor common mode inductance is 15uH, the inverter rated switching frequency is 10kHz, the rated current of each phase of the inverter is 300A effective value, the short-time peak current is 530A effective value, and the target battery heating power is 20kW. Then the transformer ratio is selected as 9, Cn = 16.9uF, at this time the neutral line current effective value is only 111A, after being evenly distributed to the three phases, each phase is only 37A, which is much less than the rated current and peak current. However, at this time, on the secondary side of the transformer, the battery heating current reaches 1000A, which can make the battery obtain a heating power of 20kW.
示例性地，谐振频率fr可以选择比正常的开关频率要高很多，比如20kHz，在需要进行加热的时候，将开关频率fs提高到接近fr。需要加热的时候温度都很低，允许提高逆变器开关频率，从而增加逆变器的发热来加热冷区液。For example, the resonant frequency fr can be selected to be much higher than the normal switching frequency, such as 20kHz, and when heating is required, the switching frequency fs is increased to be close to fr. When heating is required, the temperature is very low, allowing the inverter switching frequency to be increased, thereby increasing the inverter heating to heat the cold zone liquid.
可选地，变压器200和电池组100的连接方式，可以有多种变化，且变压器200和电池组100的数量可以是多个，这里仅做两个变压器组合的举例。例如，变压器200可以采取原边并联、串联，副边并联串联，多个副边分别应一个“电池全桥”，多个电池全桥之间进行串联、并联，等等，诸如此类的组合可以多种多样。Optionally, the connection mode of the transformer 200 and the battery pack 100 can be varied in many ways, and the number of the transformer 200 and the battery pack 100 can be multiple, and here only two transformer combinations are given as an example. For example, the transformer 200 can be connected in parallel or series on the primary side, in parallel or series on the secondary side, multiple secondary sides can each be a "battery full bridge", multiple battery full bridges can be connected in series or parallel, and so on, and there can be many combinations of this kind.
请参见图3和图4，图3为本申请实施例提供的电池堆叠的电池加热电路的电路示意图，图4为本申请实施例提供的电池串联的电池加热电路的电路示意图；其中，电池组100包括八个分电池U1～U8，以及两个变压器200。Please refer to Figures 3 and 4, Figure 3 is a circuit diagram of a battery heating circuit of a battery stack provided in an embodiment of the present application, and Figure 4 is a circuit diagram of a battery heating circuit of batteries connected in series provided in an embodiment of the present application; wherein, the battery pack 100 includes eight sub-batteries U1~U8 and two transformers 200.
在一些实施方式中，加热电池的同时，可以由电池发热去加热冷区液，然后通过热泵等方式给成员舱供暖。In some embodiments, while heating the battery, the heat generated by the battery can be used to heat the cold zone liquid, and then the crew cabin can be heated by a heat pump or other means.
在一些实施方式中，在电池中注入高频交流电流，可以用于电池内阻抗的测量，从而获知电池的温度、健康状况。In some embodiments, injecting a high-frequency alternating current into a battery can be used to measure the internal impedance of the battery, thereby obtaining the temperature and health status of the battery.
请参见图5，图5为本申请实施例提供的第一种单电池半桥的电路示意图。Please refer to FIG. 5 , which is a circuit diagram of the first single-battery half-bridge provided in an embodiment of the present application.
在一些实施场景中，如果电池组无法拆分成两个半桥，那么可以用一组电容来实现一个半桥，如图5所示，采用电容Cb1、电容Cb2构成半桥。In some implementation scenarios, if the battery pack cannot be split into two half-bridges, a group of capacitors can be used to implement a half-bridge, as shown in FIG5 , where capacitors Cb1 and Cb2 are used to form a half-bridge.
请参见图6，图6为本申请实施例提供的第二种单电池半桥的电路示意图。Please refer to FIG. 6 , which is a circuit diagram of a second single-battery half-bridge provided in an embodiment of the present application.
可选地，可以将电机三相逆变器的直流母线电容Cdc拆成两部分Cdc1和Cdc2，组成一个电容半桥。Optionally, the DC bus capacitor Cdc of the motor three-phase inverter may be split into two parts Cdc1 and Cdc2 to form a capacitor half-bridge.
请参见图7，图7为本申请实施例提供的原边电路连接电机其中一相的电路示意图。Please refer to Figure 7, which is a circuit diagram of the primary circuit connected to one phase of the motor provided in an embodiment of the present application.
示例性地，图1a至图6所示的所有连接方式，原边电路的另一端，可以不是连接电机的中性点，而是直接连接电机的一相，如图7所示。原理基本相同，只是变压器的原边，从电机的中性点的共模电压，变成了三相中某一相的电压。For example, in all the connection modes shown in FIG1a to FIG6, the other end of the primary circuit may not be connected to the neutral point of the motor, but directly connected to one phase of the motor, as shown in FIG7. The principle is basically the same, except that the primary side of the transformer changes from the common mode voltage of the neutral point of the motor to the voltage of one of the three phases.
需要注意的是，在图1a至图7所示的电路中，即使电路图中未标识，三相逆变器300默认包含直流母线电容Cdc。It should be noted that, in the circuits shown in FIG. 1 a to FIG. 7 , even if not marked in the circuit diagram, the three-phase inverter 300 includes a DC bus capacitor Cdc by default.
在本申请所提供的几个实施例中，应该理解到，各个实施例中的各功能模块可以集成在一起形成一个独立的部分，也可以是各个模块单独存在，也可以两个或两个以上模块集成形成一个独立的部分。In the several embodiments provided in the present application, it should be understood that the functional modules in each embodiment can be integrated together to form an independent part, or each module can exist separately, or two or more modules can be integrated to form an independent part.
以上所述，以上实施例仅用以说明本申请的技术方案，而非对其限制；尽管参照前述实施例对本申请进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本申请各实施例技术方案的范围。As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features therein can be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims (10)

  1. 一种基于变压器的电池加热电路，其特征在于，包括电池组、变压器、三相逆变器、加热继电器和三相电机；A transformer-based battery heating circuit, characterized in that it includes a battery pack, a transformer, a three-phase inverter, a heating relay and a three-phase motor;
    所述电池组包括第一分电池、第二分电池、第三分电池和第四分电池，所述第一分电池和所述第二分电池串联为第一电池半桥电路，所述第三分电池和所述第四分电池串联为第二电池半桥电路，所述第一电池半桥电路和所述第二电池半桥电路并联；The battery pack comprises a first sub-battery, a second sub-battery, a third sub-battery and a fourth sub-battery, the first sub-battery and the second sub-battery are connected in series to form a first battery half-bridge circuit, the third sub-battery and the fourth sub-battery are connected in series to form a second battery half-bridge circuit, and the first battery half-bridge circuit and the second battery half-bridge circuit are connected in parallel;
    所述变压器设置有原边和副边，所述副边的两端分别连接所述第一电池半桥电路的中点、所述第二电池半桥电路的中点，所述原边的一端连接预设端点集合的其中一个端点，所述预设端点集合包括所述第二电池半桥电路的中点、直流母线的正极、直流母线的负极、电池内部电平点、正负母线电容分压点、直流母线电容的中点；The transformer is provided with a primary side and a secondary side, the two ends of the secondary side are respectively connected to the midpoint of the first battery half-bridge circuit and the midpoint of the second battery half-bridge circuit, and one end of the primary side is connected to one of the endpoints of a preset endpoint set, and the preset endpoint set includes the midpoint of the second battery half-bridge circuit, the positive pole of the DC bus, the negative pole of the DC bus, the internal level point of the battery, the positive and negative bus capacitor voltage dividing point, and the midpoint of the DC bus capacitor;
    所述三相电机分别与所述原边的另一端、所述三相逆变器连接，所述三相电机通过所述加热继电器连接所述变压器。The three-phase motor is connected to the other end of the primary side and the three-phase inverter respectively, and the three-phase motor is connected to the transformer through the heating relay.
  2. 根据权利要求1所述的基于变压器的电池加热电路，其特征在于，所述三相逆变器包括三个功率开关管组件，所述功率开关管组件的一端连接所述第一电池半桥电路的一端，所述功率开关管组件的另一端连接所述第二电池半桥电路的另一端。The transformer-based battery heating circuit according to claim 1 is characterized in that the three-phase inverter includes three power switch tube assemblies, one end of the power switch tube assembly is connected to one end of the first battery half-bridge circuit, and the other end of the power switch tube assembly is connected to the other end of the second battery half-bridge circuit.
  3. 根据权利要求2所述的基于变压器的电池加热电路，其特征在于，所述功率开关管组件包括两个功率开关管，所述两个功率开关管串联。The transformer-based battery heating circuit according to claim 2 is characterized in that the power switch tube assembly includes two power switch tubes, and the two power switch tubes are connected in series.
  4. 根据权利要求2所述的基于变压器的电池加热电路，其特征在于，所述三相电机设置有三条电缆线，所述三条电缆线分别连接所述三个功率开关管组件。The transformer-based battery heating circuit according to claim 2 is characterized in that the three-phase motor is provided with three cables, and the three cables are respectively connected to the three power switch tube assemblies.
  5. 根据权利要求1所述的基于变压器的电池加热电路，其特征在于，所述电池加热电路还包括电容，所述电容和所述加热继电器串联。The transformer-based battery heating circuit according to claim 1 is characterized in that the battery heating circuit also includes a capacitor, and the capacitor is connected in series with the heating relay.
  6. 根据权利要求1所述的基于变压器的电池加热电路，其特征在于，所述电池加热电路还包括第一继电器，所述第一继电器串联在所述第一电池半桥电路的一端。The transformer-based battery heating circuit according to claim 1 is characterized in that the battery heating circuit further comprises a first relay, and the first relay is connected in series to one end of the first battery half-bridge circuit.
  7. 根据权利要求6所述的基于变压器的电池加热电路，其特征在于，所述电池加热电路还包括第二继电器，所述第二继电器串联在所述第一电池半桥电路 的另一端。The transformer-based battery heating circuit according to claim 6 is characterized in that the battery heating circuit also includes a second relay, which is connected in series to the other end of the first battery half-bridge circuit.
  8. 根据权利要求1所述的基于变压器的电池加热电路，其特征在于，所述三相电机为星形连接的三相电机。The transformer-based battery heating circuit according to claim 1 is characterized in that the three-phase motor is a star-connected three-phase motor.
  9. 根据权利要求1或8所述的基于变压器的电池加热电路，其特征在于，所述三相电机为永磁同步电机、无刷电机、异步电机中的一种。The transformer-based battery heating circuit according to claim 1 or 8 is characterized in that the three-phase motor is one of a permanent magnet synchronous motor, a brushless motor, and an asynchronous motor.
  10. 一种电动车辆，其特征在于，所述电动车辆包括如权利要求1至9任一项所述的基于变压器的电池加热电路。An electric vehicle, characterized in that the electric vehicle comprises a transformer-based battery heating circuit as described in any one of claims 1 to 9.
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CN110116653A (en) * 2019-04-19 2019-08-13 清华大学 Drive system of electric automobile, driving circuit and batteries of electric automobile heating means
WO2021048935A1 (en) * 2019-09-11 2021-03-18 田中　正一 Power switching circuit
CN114889494A (en) * 2022-05-25 2022-08-12 广汽埃安新能源汽车有限公司 Battery heating device and car
CN115042673A (en) * 2022-07-26 2022-09-13 广汽埃安新能源汽车有限公司 Battery self-heating circuit with transformer and vehicle
CN115172941A (en) * 2022-08-03 2022-10-11 广汽埃安新能源汽车有限公司 Battery self-heating circuit and control method thereof
CN115465154A (en) * 2022-10-26 2022-12-13 广汽埃安新能源汽车股份有限公司 Battery heating circuit and electric vehicle based on transformer

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