CN115447445A - Battery heating circuit, control method and electric vehicle - Google Patents
Battery heating circuit, control method and electric vehicle Download PDFInfo
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- CN115447445A CN115447445A CN202211202026.5A CN202211202026A CN115447445A CN 115447445 A CN115447445 A CN 115447445A CN 202211202026 A CN202211202026 A CN 202211202026A CN 115447445 A CN115447445 A CN 115447445A
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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
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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
- B60L3/00—Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption
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Abstract
The embodiment of the application provides a battery heating circuit, a control method and an electric vehicle, and relates to the technical field of power batteries. The battery heating circuit comprises a battery pack assembly, a power switch tube assembly, a half-bridge relay and a vehicle driving motor; the battery pack assembly comprises a first battery and a second battery which are connected in series; the power switch tube assembly comprises three half-bridge assemblies, wherein one end of each half-bridge assembly is connected with the anode of the first battery, and the other end of each half-bridge assembly is connected with the cathode of the second battery; one end of the half-bridge relay is connected between the first battery and the second battery, and the other end of the half-bridge relay is connected to one half-bridge component in the power switch tube components; the vehicle driving motor comprises three cables, and the three cables of the vehicle driving motor are respectively and correspondingly connected with the three half-bridge components. The battery heating circuit can achieve the technical effect that the battery can be self-heated in the vehicle parking state or the vehicle running state.
Description
Technical Field
The application relates to the technical field of power batteries, in particular to a battery heating circuit, a control method and an electric vehicle.
Background
At present, a new energy automobile refers to an automobile which adopts unconventional automobile fuel as a power source (or adopts conventional automobile fuel and a novel vehicle-mounted power device), integrates advanced technologies in the aspects of power control and driving of the automobile, and has advanced technical principle, new technology and new structure. The new energy automobile comprises a pure electric automobile, an extended range electric automobile, a hybrid electric automobile, a fuel cell electric automobile, a hydrogen engine automobile and the like.
In the prior art, the low-temperature performance of a power battery of a new energy automobile is poor, so that the battery temperature needs to be improved at a low temperature; conventional methods of heating the battery include indirect heating and direct heating. The indirect heating method is to heat the battery by waste heat generated by a heating resistor or other components outside the battery, such as a Positive Temperature Coefficient resistor (PTC) heating device, a metal thick film heating technology, and an electric drive system heating technology, which are well known in the art; direct heating, also known as "battery self-heating," or battery ac heating, heats a battery by passing a high frequency ac current through the battery, which heats the battery by internal resistance of the battery. The direct heating heat source is arranged in the battery, so that the heating efficiency is high, and the heating of the whole battery pack is relatively uniform. However, the conventional method for self-heating the battery by using the motor inverter and the motor is difficult to apply in a vehicle driving state because torque jitter is easily caused or the power output of the motor is easily influenced.
Disclosure of Invention
An object of the embodiments of the present application is to provide a battery heating circuit, a control method, and an electric vehicle, which can achieve a technical effect of performing battery self-heating in both a vehicle stop state and a vehicle running state.
In a first aspect, an embodiment of the present application provides a battery heating circuit, which includes a battery pack assembly, a power switching tube assembly, a half-bridge relay, and a vehicle driving motor;
the battery pack assembly comprises a first battery and a second battery, and the first battery and the second battery are connected in series;
the power switch tube assembly comprises three half-bridge assemblies, one end of each half-bridge assembly is connected with the positive electrode of the first battery, and the other end of each half-bridge assembly is connected with the negative electrode of the second battery;
one end of the half-bridge relay is connected between the first battery and the second battery, and the other end of the half-bridge relay is connected to one half-bridge component in the power switch tube components;
the vehicle driving motor comprises three cables, and the three cables of the vehicle driving motor are respectively and correspondingly connected with the three half-bridge assemblies.
In the implementation process, the battery pack assembly in the battery heating circuit is divided into a first battery and a second battery which are connected in series, the capacities, voltages and the like of the first battery and the second battery are the same, and the first battery and the second battery form a battery half bridge; the power switch tube assembly forms a three-phase inverter, any half-bridge midpoint of the three-phase inverter and the battery half-bridge midpoint are connected through a half-bridge relay; thereby this battery heating circuit is through the break-make of control power switch tube subassembly, half-bridge relay, can realize realizing under the stop state with single bridge arm/double bridge arm switch ripple/low frequency alternating current heating, driving state under let the three-phase inverter with the form driving motor of four tub three-phase inverters to the battery is heated to the electric current of a certain looks of three-phase inverter, can be in order to realize that the vehicle parking state or driving state all can carry out the technological effect of battery self-heating down.
Further, the half-bridge component comprises two power switch tubes which are connected in series, and the cable is connected between the two power switch tubes.
Furthermore, the battery heating circuit further comprises a supporting capacitor, one end of the supporting capacitor is connected with the positive electrode of the first battery, and the other end of the supporting capacitor is connected with the negative electrode of the second battery.
Further, the parameters of the first battery and the second battery are matched with each other.
Further, the battery heating circuit further comprises a positive relay and a negative relay, wherein the positive relay is connected with the positive pole of the first battery in series, and the negative relay is connected with the negative pole of the second battery in series.
In a second aspect, an embodiment of the present application provides a control method for battery heating, which is applied to the battery heating circuit described in the first aspect, wherein a half-bridge component connected to the half-bridge relay is a primary half-bridge component, and a half-bridge component not connected to the half-bridge relay is a secondary half-bridge component, and the control method for battery heating includes:
acquiring vehicle state data;
generating state information of the vehicle according to the vehicle state data, wherein the state information comprises a parking power-off state, a normal driving state, a parking heating battery state and a driving heating battery state;
performing the following processing on the battery heating circuit according to the state information:
the state information is a power-off state when the vehicle is stopped, and the positive relay, the negative relay and the half-bridge relay are controlled to be switched off;
the state information is a normal driving state, the positive relay and the negative relay are controlled to be closed, and the half-bridge relay is switched off;
the state information is a state of heating a battery when the vehicle is stopped, the positive relay, the negative relay and the half-bridge relay are controlled to be closed, the main half-bridge assembly does not work, and one or two of the secondary half-bridge assemblies work;
the state information is the driving heating battery state, controls positive relay negative relay half-bridge relay is closed, main half-bridge subassembly is out of work, inferior half-bridge subassembly work, the power switch tube subassembly is four tubes three-phase inverter.
In the implementation process, the positive relay, the negative relay, the half-bridge relay and the power switch tube assembly are respectively subjected to different control strategies according to different vehicle states, so that the technical effect of battery self-heating in the vehicle parking state or the driving state is achieved.
Further, in the step of the state information being the state of the heating battery during the parking, the current of the half-bridge relay is a switching ripple current or a PWM-modulated low-frequency alternating current.
Further, the step of the state information being the state of the heating battery of the traveling crane comprises:
and adjusting the working current of the vehicle driving motor according to the required torque and the required current.
In the implementation process, the working current of the vehicle driving motor is maintained to be a certain value according to the battery heating requirement, so that the battery heating effect is ensured, and the torque requirement of vehicle driving is also ensured to be met.
Further, after the step of generating the state information of the vehicle according to the vehicle state data, the method further includes:
judging whether the state information is updated or not, if so, controlling the three half-bridge components, the half-bridge relay and the half-bridge relay to be disconnected and switched to a preset form; if not, executing the next step.
In the implementation process, when the heating mode and the non-heating mode of the vehicle are switched, the three half-bridge components and the half-bridge relay are controlled to be switched off in a transition state, and then the half-bridge components and the half-bridge relay are controlled in a corresponding strategy, so that the normal operation of a circuit is guaranteed.
In a third aspect, an embodiment of the present application provides an electric vehicle including the battery heating circuit of any one of the first aspect.
Additional features and advantages of the disclosure will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the above-described technology disclosed herein.
In order to make the aforementioned objects, features and advantages of the present application comprehensible, preferred embodiments accompanied with figures are described in detail below.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments of the present application will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and that those skilled in the art can also obtain other related drawings based on the drawings without inventive efforts.
Fig. 1 is a schematic circuit diagram of a battery heating circuit according to an embodiment of the present disclosure;
fig. 2 is a schematic flowchart of a control method for heating a battery according to an embodiment of the present disclosure;
fig. 3 is a schematic diagram of a rotational speed-torque of a vehicle driving motor according to an embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. Meanwhile, in the description of the present application, the terms "first", "second", and the like are used only for distinguishing the description, and are not to be construed as indicating or implying relative importance.
The embodiment of the application provides a battery heating circuit, a control method and an electric vehicle, which can be applied to the self-heating process of a vehicle power battery; the battery pack assembly in the battery heating circuit is divided into a first battery and a second battery which are connected in series, the capacities, voltages and the like of the first battery and the second battery are the same, and the first battery and the second battery form a battery half bridge; the power switch tube assembly forms a three-phase inverter, any half-bridge midpoint of the three-phase inverter and the battery half-bridge midpoint are connected through a half-bridge relay; therefore, the battery heating circuit can realize the heating of switching ripple/low-frequency alternating current by using a single bridge arm/double bridge arms in a stop state and drive the motor of the three-phase inverter in a four-tube three-phase inverter mode in a driving state by controlling the on-off of the power switch tube assembly and the half-bridge relay, and can heat the battery by using the current of a certain phase of the three-phase inverter, thereby realizing the technical effect of self-heating the battery in a vehicle parking state or a driving state.
In some implementation scenarios, parameters such as capacities and voltages of the first battery and the second battery in the battery heating circuit provided by the embodiment of the present application may be asymmetric, and compared with the symmetric situation, the heating of the batteries is unbalanced, and the driving capability will be reduced to some extent in a driving state.
Referring to fig. 1, fig. 1 is a schematic circuit diagram of a battery heating circuit according to an embodiment of the present disclosure, where the battery heating circuit includes a battery pack assembly 100, a power switching tube assembly 200, a half-bridge relay Ka, and a vehicle driving motor 300.
Illustratively, the battery pack assembly includes a first battery U1 and a second battery U2, the first battery U1 and the second battery U2 being connected in series.
Illustratively, the battery pack assembly 100 is divided into two parts of the first battery U1 and the second battery U2 connected in series, and the capacities, voltages, and so on of the first battery U1 and the second battery U2 are the same, i.e., the first battery U1 and the second battery U2 are two parts that are interchangeable in terms of electrical properties. In this case, the first battery U1 and the second battery U2 form a "battery half-bridge".
Illustratively, the power switch tube assembly 200 includes three half-bridge assemblies, one end of each half-bridge assembly is connected to the positive electrode of the first battery U1, and the other end of each half-bridge assembly is connected to the negative electrode of the second battery U2.
Illustratively, one half-bridge assembly includes two power switching tubes; as shown in fig. 1, power switching tube assembly 200 includes six powers Q1-Q6.
For example, the power switch tube is a triode which can bear large current, has small leakage current and has good saturation conduction and cut-off characteristics under certain conditions, the amplification performance of the triode can be not considered too much, and the control electrode of the triode is related to the magnitude or direction of base current through a collector and an emitter.
In some embodiments, the power switch is generally a Semiconductor switch device such as an Insulated Gate Bipolar Transistor (IGBT) or a Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET/MOS); it should be noted that the type of power switch tube is used herein by way of example only and not by way of limitation.
Illustratively, one end of the half-bridge relay Ka is connected between the first battery U1 and the second battery U2, and the other end of the illustrated half-bridge relay Ka is connected to one of the power switch tube assemblies 200.
Illustratively, the vehicle driving motor 300 includes three cables, and the three cables of the vehicle driving motor 300 are respectively connected to three half-bridge assemblies.
Illustratively, the power switching tube assembly 200 forms a three-phase inverter, and the midpoint of any one half-bridge assembly of the three-phase inverter is connected to the midpoint of the battery half-bridge via a half-bridge relay Ka.
In some embodiments, the vehicle driving motor 300 may be a permanent magnet synchronous motor, a dc brushless motor, or a three-phase asynchronous motor.
Illustratively, in the battery heating circuit, the battery pack assembly 100 is divided into two parts, namely a first battery U1 and a second battery U2, which are connected in series, wherein the capacities, voltages and the like of the first battery U1 and the second battery U2 are the same, and the first battery U1 and the second battery U2 form a battery half bridge; the power switch tube assembly 200 forms a three-phase inverter, and any half-bridge midpoint of the three-phase inverter is connected with the battery half-bridge midpoint through a half-bridge relay Ka; therefore, the battery heating circuit can realize the heating of switching ripple/low-frequency alternating current by using a single bridge arm/double bridge arms in a stop state and the driving of a three-phase inverter in a four-tube three-phase inverter in a driving state by controlling the on-off of the power switch tube assembly 200 and the half-bridge relay Ka, and can heat the battery by using the current of a certain phase of the three-phase inverter, thereby realizing the technical effect of self-heating of the battery in a vehicle stop state or a driving state.
Illustratively, the half-bridge assembly includes two power switching tubes connected in series, and a cable of the vehicle drive motor is connected between the two power switching tubes.
Illustratively, as shown in fig. 1, the power switching tubes Q1 to Q6 are combined two by two to form a half-bridge component, that is, the power switching tubes Q1 and Q2 are combined, the power switching tubes Q3 and Q4 are combined, and the power switching tubes Q5 and Q6 are combined.
Exemplarily, the battery heating circuit further comprises a supporting capacitor, one end of the supporting capacitor is connected with the positive electrode of the first battery U1, and the other end of the supporting capacitor is connected with the negative electrode of the second battery U2; it should be noted that the support capacitor is a part of the three-phase inverter circuit, which is not shown in the circuit diagram of fig. 1.
Illustratively, the parameters of the first battery U1 and the second battery U2 are matched with each other; optionally, when the parameters of the first battery U1 and the second battery U2 are matched with each other, the parameters of the two batteries may be the same or different: when parameters are the same, the heating power of the two batteries is the same, and the heating is balanced; when parameters are different, heating power of the two batteries is different, heating imbalance is caused, and the whole circuit can operate according to a preset mode.
Illustratively, the battery heating circuit further comprises a positive relay Kp and a negative relay Kn, wherein the positive relay Kp is connected in series with the positive pole of the first battery, and the negative relay Kn is connected in series with the negative pole of the second battery.
Exemplarily, as shown in fig. 1, the transmission line (high voltage dc bus) of the battery pack assembly 100 is connected through a positive relay Kp and a negative relay Kn; the main load on the transmission line of the battery pack assembly 100 is a power switch tube assembly 200, and a power circuit of the power switch tube assembly is a three-phase inverter circuit composed of 6 power switch tubes Q1, Q2, Q3, Q4, Q5 and Q6 as shown in fig. 1; the power switch tube Q1 and Q2, the power switch tubes Q3 and Q4 and the power switch tubes Q5 and Q6 are combined into three half-bridge components in pairs; the power switching tube assembly 200 is connected to a vehicle driving motor 300 through three ac cables.
Referring to fig. 2, fig. 2 is a schematic flow chart of a battery heating control method according to an embodiment of the present disclosure, the battery heating control method is applied to the battery heating circuit shown in fig. 1, in which a half-bridge component connected to a half-bridge relay Ka is a main half-bridge component, and a half-bridge component not connected to the half-bridge relay Ka is a sub-half-bridge component; the control method for heating the battery comprises the following steps:
s100: acquiring vehicle state data;
s200: generating state information of the vehicle according to the vehicle state data, wherein the state information comprises a power-off state when the vehicle is stopped, a normal driving state, a parking heating battery state and a driving heating battery state;
s300: performing the following processing on the battery heating circuit according to the status information: the state information is a power-off state when the vehicle is stopped, and the positive relay, the negative relay and the half-bridge relay are controlled to be switched off; the state information is a normal driving state, the positive relay and the negative relay are controlled to be closed, and the half-bridge relay is switched off; the state information is a state of heating the battery when the vehicle is stopped, and controls the positive relay, the negative relay and the half-bridge relay to be closed, the main half-bridge assembly does not work, and one or two of the secondary half-bridge assemblies work; the state information is the driving heating battery state, and control positive relay, negative relay, half-bridge relay are closed, and the main half-bridge subassembly is out of work, and the work of inferior half-bridge subassembly, power switch tube assembly are four tubes three-phase dc-to-ac converter.
It should be noted that, the combination of the two sub half-bridge modules and the battery half-bridge is a complete four-tube three-phase inverter.
Illustratively, different control strategies are respectively carried out on the positive relay, the negative relay, the half-bridge relay and the power switch tube assembly according to different vehicle states, so that the technical effect that the battery can be self-heated in the vehicle parking state or the driving state is achieved.
Illustratively, in conjunction with fig. 1 and 2, the half-bridge components connected to the half-bridge relay Ka are primary half-bridge components (power switches Q1 and Q2), and the half-bridge components not connected to the half-bridge relay Ka are secondary half-bridge components (power switches Q3 and Q4 and power switches Q5 and Q6).
In the step of the state information being the state of the heating battery during the parking, the current of the half-bridge relay is a switching ripple current or a PWM modulated alternating current.
Illustratively, pulse Width Modulation (PWM) is an analog control method, which modulates the bias of the base of a transistor or the gate of a MOS transistor according to the variation of the corresponding load to change the conduction time of the transistor or the MOS transistor, thereby realizing the control of voltage or current.
Exemplarily, the step of using the state information in S300 as the vehicle heating battery state includes:
and adjusting the working current of the vehicle driving motor according to the required torque and the battery heating required current.
Illustratively, the working current of the vehicle driving motor is maintained at a certain level according to the battery heating requirement, thereby ensuring the battery heating effect.
Exemplarily, at S200: after the step of generating the state information of the vehicle from the vehicle state data, the method further comprises:
judging whether the state information is updated or not, if so, controlling the three half-bridge components and the half-bridge relay to be disconnected and switching to a preset form; if not, executing the next step.
Illustratively, when a heating mode and a non-heating mode of a vehicle are switched, a transition state is firstly entered, three half-bridge components and a half-bridge relay are controlled to be disconnected, and then the half-bridge components are correspondingly controlled in a strategy, so that the normal operation of a circuit is guaranteed.
In some implementation scenarios, with reference to fig. 2, the state information of the vehicle includes a power-off state when the vehicle is parked, a normal driving state, a parking heating battery state, and a driving heating battery state, and a specific control strategy example of the battery heating control method provided in the embodiment of the present application is as follows:
1) Parking and powering off: at the moment, the power system does not work, and the positive relay Kp, the negative relay Kn and the half-bridge relay Ka are all switched off;
2) And (4) normal driving state: the positive relay Kp and the negative relay Kn are closed, and the half-bridge relay Ka is disconnected; at the moment, the battery is not required to be heated automatically, a three-phase inverter formed by the power switch tube assembly 200 controls a vehicle driving motor to operate according to the requirement of the whole vehicle, and the operation is not different from that of a conventional power system;
3) Parking and heating the battery state: at this time, the positive relay Kp, the negative relay Kn, and the half-bridge relay Ka are all closed. The power switch tubes Q1 and Q2 do not work, and one or two of the two half-bridge components of the power switch tubes Q3 and Q4 and the power switch tubes Q5 and Q6 work simultaneously, so that alternating current I flows AM (i.e., the current of the half-bridge relay Ka) flows between the points a and M; alternatively, the alternating current I AM The form of the voltage source can be a switching ripple or a low-frequency alternating current obtained by PWM pulse width modulation. The current of the half-bridge relay Ka is the switching ripple current or PWM low-frequency alternating current under the condition of heating the battery when the vehicle is stopped:
3.1 ) switching ripple current, referred to as I AM Has the same frequency as the switching frequency of the half-bridge assembly. Illustratively, if only bridge arms of the power switching tubes Q3 and Q4 are selected to work, the voltage of a point B relative to a point M is a square wave with positive and negative symmetry; if the half-bridges of the power switching tubes Q3 and Q4 and the half-bridges of the power switching tubes Q5 and Q6 are selected to work simultaneously, the voltage waveforms of the point B and the point C are the same, and the voltages corresponding to the point M are square waves with positive and negative symmetry; the double-bridge arm is superior to the single-bridge arm in working because the current ripple is doubled compared with the single-bridge arm under the same switching frequency;
3.2 PWM pulse-width modulated Low frequency alternating Current, referred to as Current I AM Is low frequency, which is significantly lower than the switching frequency of the half-bridge assembly. If the power switching tubes Q3 and Q4 are selected to work in a half-bridge mode at the moment, the PWM duty ratio is modulated to I AM The current is controlled so that I AM The current oscillates in a sine wave or other alternating symmetrical waveform; similarly, the arms of the power switching tubes Q5 and Q6 can also participate in the operation. The power switching tubes Q5 and Q6 can keep the same phase switch with the power switching tubes Q3 and Q4, and the power switching tubes Q3 and Q4 and the two bridge arms of the power switching tubes Q5 and Q6 can also be driven by staggered PWM waves;
4) The state of the battery is heated by the travelling crane: at the moment, the positive relay Kp, the negative relay Kn and the half-bridge relay Ka are all closed; the half-bridges of the power switch tubes Q1 and Q2 do not work, and the two half-bridge components of the power switch tubes Q3 and Q4 and the power switch tubes Q5 and Q6 work. At this time, the voltage of the phase a corresponding to the vehicle driving motor 300 is always zero with respect to the point M, and the voltages of the phase B and the phase C can be selected from + Udc/2 and-Udc/2, so that according to the Space Modulation theory (SVPWM), the available voltage Vector range of the motor in the stator coordinate system is changed into a rhombus from the hexagon of the conventional design. Considering that the steady-state voltage waveform is a circular trace in the case of motor operation, it can be considered that the ac voltage output capability of the inverter to the motor at this time is reduced to half that of the conventional design. At the moment, the three-phase inverter with 6 power switching tubes is degenerated into a four-tube three-phase inverter;
as shown in fig. 3, fig. 3 is a schematic diagram of a rotation speed and a torque of a driving motor of a vehicle according to an embodiment of the present application, where a heating mode is a heating battery state in a running mode, and a normal mode is a power-off state in a parking mode or a normal running state; in this case, the "torque-rotation speed" characteristic of vehicle drive motor 300 itself is contracted, and the dynamic property is affected to some extent, but this is not acceptable. Importantly, since the vehicle can normally run, the three phases a, B and C of the vehicle driving motor 300 will have ac current flowing through it, and the frequency of the ac current is proportional to the motor speed. For motor phase a, the ac phase current flows into the battery M, thereby heating the entire battery.
5) The operating current of the vehicle driving motor 300 is adjusted in a state where the vehicle is running to heat the battery. In general, the current of the permanent magnet synchronous motor complies with the minimum current principle, that is, in a low-speed non-field weakening region, the current operating point of the vehicle driving motor 300 is located at the intersection point of the required torque line and the MTPA (maximum torque per unit current); in the weak magnetic region, the motor current operating point is located at the intersection point of the required torque and the voltage limiting ellipse (the intersection point of the two intersection points where the current is smaller). In the embodiment of the present application, in order to ensure the battery heating effect in the driving state, the current of the vehicle driving motor 300 needs to be maintained at a certain level, such as the current I AM The amplitude is up to several hundred amperes; if the minimum current principle is continuously adopted, the motor current is mostly usedIt is small and difficult to heat the battery. The following principles need to be changed at this time: whether the weak magnetic region exists or not, in the voltage limit range, the working current is preferentially determined according to the intersection point of the equal torque line of the required torque and the current circle of the heating required current; if the intersection point does not exist, determining a working current point according to a conventional mode;
6) Switching between heating mode and normal mode. If it is desired to stop heating, or to switch into a heating mode from a normal circuit operating state, whether the vehicle is stationary or in motion, the control strategy needs to be switched as follows. Whether the heating state is currently available or not, when the state needs to be switched, a transition state is firstly entered: the power switch tubes Q1 to Q6 are all disconnected. The half-bridge relay Ka is then closed or opened as required. After the half-bridge relay Ka completes switching, the control can be continued according to the heating or normal state. Such a switching control strategy is followed regardless of the stationary state or the traveling state. In a driving state, because the power switch tubes Q1-Q6 are semiconductor switches, the switching is quick and can be completed within a few microseconds, and the half-bridge relay Ka is a mechanical relay generally but can be completed within 0.1s, the whole switching process can be completed quickly, the interruption time of power is very small, and the influence on the normal driving of the whole vehicle is very small.
7) The heating mode is not enabled at a low rotation speed of the vehicle drive motor 300. If the rotational speed of the vehicle drive motor 300 is low, so that if the heating is performed in the running state at this time, I AM The low current frequency will cause low frequency charging and discharging of the battery, which will adversely affect the battery life. Therefore, at a lower rotation speed, the heating function is not enabled at this time in consideration of the battery life. The threshold rotational speed may be set according to the battery temperature and the amount of electricity. Generally, the problem is not great when the current frequency is higher than 50Hz, and the vehicle speed is generally about 10kph at the moment.
Illustratively, the embodiment of the application provides an electric vehicle, and the electric vehicle comprises a battery heating circuit shown in fig. 1.
Illustratively, the battery heating circuit and the control method provided by the embodiment of the application can realize the heating of the switching ripple/low-frequency alternating current by using a single bridge arm/double bridge arms under a static state; in the vehicle-heating battery state, the inverter is caused to drive the motor in the form of a four-tube three-phase inverter to heat the battery from the a-phase current of the vehicle-driving motor 300. In the state of heating the battery in the driving, no matter the required torque, the minimum motor current is maintained according to the requirement of heating the battery. Therefore, the battery heating circuit and the control method can heat the power battery no matter the vehicle is in a running state or a static state.
In the several embodiments provided in the present application, it should be understood that each functional module in each embodiment may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.
The above description is only an example of the present application and is not intended to limit the scope of the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.
The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.
It should be noted that, in this document, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrases "comprising a," "8230," "8230," or "comprising" does not exclude the presence of additional like elements in a process, method, article, or apparatus that comprises the element.
Claims (10)
1. A battery heating circuit is characterized by comprising a battery pack assembly, a power switch tube assembly, a half-bridge relay and a vehicle driving motor;
the battery pack assembly comprises a first battery and a second battery, and the first battery and the second battery are connected in series;
the power switch tube assembly comprises three half-bridge assemblies, one end of each half-bridge assembly is connected with the positive electrode of the first battery, and the other end of each half-bridge assembly is connected with the negative electrode of the second battery;
one end of the half-bridge relay is connected between the first battery and the second battery, and the other end of the half-bridge relay is connected to one half-bridge component in the power switch tube components;
the vehicle driving motor comprises three cables, and the three cables of the vehicle driving motor are respectively and correspondingly connected with the three half-bridge assemblies.
2. The battery heating circuit of claim 1, wherein the half-bridge assembly comprises two power switching tubes connected in series, the cable being connected between the two power switching tubes.
3. The battery heating circuit of claim 1, further comprising a support capacitor, wherein one end of the support capacitor is connected to the positive electrode of the first battery, and the other end of the support capacitor is connected to the negative electrode of the second battery.
4. The battery heating circuit of claim 1, wherein the parameters of the first battery and the second battery are matched to each other.
5. The battery heating circuit according to any one of claims 1 to 4, further comprising a positive relay connected in series with a positive pole of the first battery and a negative relay connected in series with a negative pole of the second battery.
6. A control method for battery heating, which is applied to the battery heating circuit of claim 5, wherein the half-bridge component connected to the half-bridge relay is a primary half-bridge component, and the half-bridge component not connected to the half-bridge relay is a secondary half-bridge component, the control method for battery heating comprises:
acquiring vehicle state data;
generating state information of the vehicle according to the vehicle state data, wherein the state information comprises a power-off state when the vehicle is parked, a normal driving state, a parking heating battery state and a driving heating battery state;
performing the following processing on the battery heating circuit according to the state information:
the state information is a power-off state when the vehicle is stopped, and the positive relay, the negative relay and the half-bridge relay are controlled to be switched off;
the state information is a normal driving state, the positive relay and the negative relay are controlled to be closed, and the half-bridge relay is switched off;
the state information is a state of heating a battery during parking, the positive relay, the negative relay and the half-bridge relay are controlled to be closed, the main half-bridge assembly does not work, and one or two of the secondary half-bridge assemblies work;
the state information is the driving heating battery state, controls positive relay negative relay half-bridge relay is closed, main half-bridge subassembly is out of work, inferior half-bridge subassembly work, the power switch tube subassembly is four tubes three-phase inverter.
7. The battery heating control method according to claim 6, wherein in the step of the state information being a battery heating state during shutdown, the current of the half-bridge relay is a switching ripple current or a PWM modulated low frequency alternating current.
8. The method according to claim 7, wherein the step of the state information being a battery heating state of the traveling crane comprises:
and adjusting the working current of the vehicle driving motor according to the magnitude of the required torque and the required current.
9. The battery heating control method according to claim 6, wherein after the step of generating the state information of the vehicle from the vehicle state data, the method further comprises:
judging whether the state information is updated or not, if so, controlling the three half-bridge components to be disconnected and switching to a preset form; if not, executing the next step.
10. An electric vehicle characterized in that the electric vehicle comprises the battery heating circuit according to any one of claims 1 to 5.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202211202026.5A CN115447445A (en) | 2022-09-29 | 2022-09-29 | Battery heating circuit, control method and electric vehicle |
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| CN202211202026.5A CN115447445A (en) | 2022-09-29 | 2022-09-29 | Battery heating circuit, control method and electric vehicle |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116722780A (en) * | 2023-06-07 | 2023-09-08 | 江苏威进智控科技有限公司 | Active heating method of power battery based on motor current and PWM configuration |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116722780A (en) * | 2023-06-07 | 2023-09-08 | 江苏威进智控科技有限公司 | Active heating method of power battery based on motor current and PWM configuration |
| CN116722780B (en) * | 2023-06-07 | 2024-02-13 | 江苏威进智控科技有限公司 | Active heating method of power battery based on motor current and PWM configuration |
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