CN109600036B

CN109600036B - Power converter, power conversion system and control method of power converter

Info

Publication number: CN109600036B
Application number: CN201810642039.1A
Authority: CN
Inventors: 杨家诚; 黄宸斌; 詹睿腾
Original assignee: Delta Electronics Inc
Current assignee: Delta Electronics Inc
Priority date: 2017-10-03
Filing date: 2018-06-21
Publication date: 2020-08-25
Anticipated expiration: 2038-06-21
Also published as: TW201916561A; TWI680633B; CN109600036A

Abstract

The application provides a power converter, a power conversion system and a control method of the power converter. The power converter comprises a power conversion circuit, a high-voltage control circuit, a low-voltage control circuit and a driving circuit. The power conversion circuit is used for receiving the high-voltage direct-current voltage from the high-voltage side and converting the high-voltage direct-current voltage into low-voltage direct-current voltage to be output to the low-voltage side. The high-voltage control circuit is electrically coupled to the high-voltage side and used for detecting the high-voltage direct current voltage and outputting a first control signal according to the high-voltage direct current voltage. The low-voltage control circuit is electrically coupled to the low-voltage side and used for detecting the low-voltage direct-current voltage and outputting a second control signal according to the low-voltage direct-current voltage. The driving circuit is used for selectively outputting a driving signal according to the first control signal or the second control signal to drive the power conversion circuit.

Description

Power converter, power conversion system and control method of power converter

Technical Field

The present disclosure relates to power conversion systems, and particularly to a power conversion system for a vehicle.

Background

Recently, with the popularization of environmental awareness, the development of Electric Vehicles (EV) or Hybrid Electric Vehicles (HEV) using Electric energy as a power source to replace conventional vehicles using fossil fuel as a power source has gradually become an important target in the automobile field.

However, when the supply and demand of the generator end and the load end in the vehicle power system are unbalanced, the overvoltage or undervoltage protection mechanism is started due to unstable voltage, so that the power system stops working, the system reliability is reduced, and the vehicle cannot run.

Disclosure of Invention

One embodiment of the present disclosure is a power converter. The power converter comprises a power conversion circuit, a high-voltage control circuit, a low-voltage control circuit and a driving circuit. The power conversion circuit is used for receiving a high-voltage direct-current voltage from a high-voltage side and converting the high-voltage direct-current voltage into a low-voltage direct-current voltage to be output to a low-voltage side. The high-voltage control circuit is electrically coupled to the high-voltage side and used for detecting the high-voltage direct current voltage and outputting a first control signal according to the high-voltage direct current voltage. The low-voltage control circuit is electrically coupled to the low-voltage side and used for detecting the low-voltage direct-current voltage and outputting a second control signal according to the low-voltage direct-current voltage. The driving circuit is used for selectively outputting a driving signal to drive the power conversion circuit according to the first control signal or the second control signal.

In some embodiments, the high voltage control circuit is further configured to receive a high voltage command from a processing circuit, and output the first control signal to the driving circuit according to the high voltage command, so that the driving circuit controls the high voltage dc voltage to be stabilized at a corresponding target voltage value.

In some embodiments, the high voltage control circuit comprises: a first voltage dividing circuit for dividing the high voltage DC voltage to output a first voltage detection signal; a first compensation circuit electrically coupled between the first voltage divider circuit and the driving circuit for receiving the first voltage detection signal; and a first terminal of the first comparison amplifier is used for receiving the high-voltage command, a second terminal of the first comparison amplifier is electrically coupled to the first compensation circuit, and an output terminal of the first comparison amplifier is electrically coupled to the driving circuit.

In some embodiments, the low voltage control circuit is further configured to receive a low voltage command from a processing circuit, and output the second control signal to the driving circuit according to the low voltage command, so that the driving circuit controls the low voltage dc voltage to be stabilized at a corresponding target voltage value.

In some embodiments, the low voltage control circuit comprises: a second voltage dividing circuit for dividing the low voltage DC voltage to output a second voltage detection signal; a second compensation circuit, electrically coupled between the second voltage divider circuit and the driving circuit, for receiving the second voltage detection signal; and a second comparison amplifier, a first end of the second comparison amplifier is used for receiving the low-voltage command, a second end of the second comparison amplifier is electrically coupled to the second compensation circuit, and an output end of the second comparison amplifier is electrically coupled to the driving circuit.

In some embodiments, the power converter further comprises: the output current control circuit is electrically coupled to the low-voltage side and used for detecting an output current of the power supply conversion circuit, receiving an output current command from a processing circuit and outputting a third control signal according to the output current and the output current command.

In some embodiments, the output current control circuit comprises: a current detection circuit for outputting an output current detection signal according to the output current; a third compensation circuit, electrically coupled between the current detection circuit and the driving circuit, for receiving the output current detection signal; and a third comparison amplifier, a first end of the third comparison amplifier is used for receiving the output current command, a second end of the third comparison amplifier is electrically coupled to the third compensation circuit, and an output end of the third comparison amplifier is electrically coupled to the driving circuit.

Another embodiment of the present disclosure is a power conversion system. The power conversion system comprises a direct current generator, a power conversion circuit, a high-voltage control circuit, a low-voltage control circuit, a processing circuit and a driving circuit. The DC generator is used for outputting a high-voltage DC voltage. A high-voltage side of the power conversion circuit is electrically coupled to the dc generator for converting the high-voltage dc voltage into a low-voltage dc voltage and outputting the low-voltage dc voltage to a low-voltage side of the power conversion circuit. The high-voltage control circuit is electrically coupled to the high-voltage side and used for detecting the high-voltage direct current voltage and correspondingly outputting a first control signal. The low-voltage control circuit is electrically coupled to the low-voltage side and used for detecting the low-voltage direct-current voltage and correspondingly outputting a second control signal. The processing circuit is used for respectively outputting a high-voltage command and a low-voltage command to the high-voltage control circuit and the low-voltage control circuit so as to control whether the high-voltage control circuit and the low-voltage control circuit are started or not. The driving circuit is used for selectively outputting a driving signal to drive the power conversion circuit according to the first control signal or the second control signal.

In some embodiments, the power conversion system further comprises: and the high-voltage side energy storage device is electrically coupled to the direct-current generator and the high-voltage side of the power conversion circuit. When the high-voltage side energy storage device is disconnected with the direct-current generator or abnormal conditions occur, the processing circuit is used for outputting the corresponding high-voltage command to control the high-voltage control circuit to output the first control signal to the driving circuit according to the high-voltage command, so that the driving circuit controls the high-voltage direct-current voltage to be stabilized at a corresponding target voltage value.

In some embodiments, when the high-side energy storage device is disconnected from the dc generator or an abnormality occurs, the processing circuit is further configured to output the corresponding low-voltage command to control the low-voltage control circuit to turn off.

In some embodiments, the power conversion system further comprises: and the output current control circuit is electrically coupled to the low-voltage side and used for detecting an output current of the power supply conversion circuit and outputting a third control signal according to the output current. The processing circuit is used for outputting an output current command to control whether the output current control circuit is started or not, and the driving circuit is further used for selectively outputting the driving signal according to the first control signal, the second control signal or the third control signal.

In some embodiments, when the high-side energy storage device operates normally, the processing circuit is configured to output the corresponding high-voltage command, the corresponding low-voltage command, and the corresponding output current command to control one of the low-voltage control circuit and the output current control circuit to be activated.

In some embodiments, when the low voltage control circuit is activated, the low voltage control circuit is configured to output the second control signal to the driving circuit according to the low voltage command, so that the driving circuit controls the low voltage dc voltage to be stabilized at a corresponding target voltage value, and the output current control circuit is turned off according to the corresponding output current command.

In some embodiments, when the output current control circuit is activated, the output current control circuit is configured to output the third control signal to the driving circuit according to the output current command, so that the driving circuit controls the output current to be stabilized at a corresponding target current value, and the low voltage control circuit is turned off according to the corresponding low voltage command.

In some embodiments, the high voltage control circuit is turned off according to the corresponding high voltage command when the high side energy storage device is operating normally.

Another embodiment of the present disclosure is a method for controlling a power converter. The control method of the power converter comprises the following steps: a power conversion circuit converts a high-voltage DC voltage at a high-voltage side into a low-voltage DC voltage and outputs the low-voltage DC voltage to a low-voltage side; selectively activating, by a processing circuit, a high voltage control circuit electrically coupled to the high voltage side or a low voltage control circuit electrically coupled to the low voltage side; when the high-voltage control circuit is started, detecting the high-voltage direct current voltage and correspondingly outputting a first control signal through the high-voltage control circuit; when the low-voltage control circuit is started, detecting the low-voltage direct current voltage and correspondingly outputting a second control signal through the low-voltage control circuit; and a driving circuit outputs a driving signal to drive the power conversion circuit according to the first control signal or the second control signal so as to control the high-voltage direct-current voltage corresponding to the first control signal or control the low-voltage direct-current voltage corresponding to the second control signal.

In some embodiments, the method for controlling a power converter further includes: when a high-voltage side energy storage device coupled to the high-voltage side is disconnected with a direct current generator or is abnormal, outputting a corresponding high-voltage command to the high-voltage control circuit through the processing circuit; outputting the first control signal to the driving circuit by the high-voltage control circuit according to the high-voltage command; and controlling the high-voltage direct current voltage to be stabilized at a corresponding target voltage value by the driving circuit according to the first control signal.

Drawings

Fig. 1 is a schematic diagram of a power conversion system according to some embodiments of the present application.

Fig. 2A and 2B are schematic diagrams illustrating an operation of a power converter according to some embodiments of the disclosure.

Fig. 3 is a schematic diagram of a power conversion system according to another embodiment of the present application.

Fig. 4A to 4C are schematic diagrams illustrating an operation of a power converter according to some embodiments of the disclosure.

Fig. 5 is a flowchart illustrating a control method of a power converter according to some embodiments of the disclosure.

Description of reference numerals:

100 power conversion system

110 D.C. generator

120 power converter

122 power supply conversion circuit

124 high voltage control circuit

126 low voltage control circuit

127 output current control circuit

128 driving circuit

130 high-pressure side energy storage device

140 processing circuit

150 low-voltage side energy storage device

170 low-voltage load device

210. 230RC filter circuit

220. 260 voltage division circuit

240. 280, 290 compensation circuit

270 current detection circuit

900 control method

S910, S920, S930, S940 and S950

High voltage dc voltage of V1

V2 low-voltage DC voltage

R1-R10 resistor

OP 1-OP 3 comparison amplifier

D1, D2 and D3 rectifying element

Io output current

PWM drive signal

CT 1-CT 3 control signals

HVcmd, HVdis high voltage command

LVcmd, LVdis low voltage command

Icmd and Idis output current command

Vd1, Vd2 voltage detection signal

Vd3 output current detection signal

Detailed Description

The following detailed description of the embodiments of the present application will be provided in conjunction with the accompanying drawings for better understanding, but the embodiments are not intended to limit the scope of the present disclosure, the structural operations are not intended to limit the execution sequence thereof, and any structure resulting from the rearrangement of elements to produce an apparatus with equivalent technical effects is intended to be within the scope of the present disclosure. Moreover, the drawings are for illustrative purposes only and are not drawn to scale in accordance with industry standard and conventional practice, and the dimensions of the various features may be arbitrarily increased or decreased for clarity of illustration. In the following description, the same elements will be described with the same reference numerals for ease of understanding.

The term (terms) used throughout the specification and claims has the ordinary meaning as commonly understood in each term used in the art, in the disclosure herein, and in the specific context, unless otherwise indicated. Certain words used to describe the disclosure are discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art in describing the disclosure.

Furthermore, as used herein, the terms "comprising," including, "" having, "" containing, "and the like are open-ended terms that mean" including, but not limited to. Further, as used herein, "and/or" includes any and all combinations of one or more of the associated listed items.

When an element is referred to as being "connected" or "coupled," it can be referred to as being "electrically connected" or "electrically coupled. "connected" or "coupled" may also be used to indicate that two or more elements are in mutual engagement or interaction. Moreover, although terms such as "first," "second," …, etc., may be used herein to describe various elements, these terms are used merely to distinguish one element or operation from another element or operation described in similar technical terms. Unless the context clearly dictates otherwise, the terms do not specifically refer or imply an order or sequence nor are they intended to limit the invention.

Please refer to fig. 1. Fig. 1 is a schematic diagram of a power conversion system 100 according to some embodiments of the present application. As shown in fig. 1, in some embodiments, the power conversion system 100 includes a dc generator 110, a power converter 120, a high-side energy storage device 130, a processing circuit 140, a low-side energy storage device 150, and a low-voltage load device 170. In some embodiments, the power conversion system 100 may be used in an Electric Vehicle (EV) or Hybrid Electric Vehicle (HEV) system, and converts the high-voltage dc voltage V1 output by the dc generator 110 on the high-voltage side into a low-voltage dc voltage V2 through the cooperative operation of the power converter 120 and the processing circuit 140, and provides the output current Io to the low-voltage energy storage device 150 and the low-voltage load device 170 on the low-voltage side. Therefore, the electric power required by various devices in the in-vehicle system can be supplied.

For example, in some embodiments, the dc generator 110 may output a high voltage dc voltage V1 of about 48V. The power converter 120 can convert the low voltage dc voltage V2 to, for example, about 12V to supply the power requirements of the car audio system, the car electronics such as the tachograph, etc. It should be noted that the above values and applications are only illustrative and not intended to limit the present application.

As shown in fig. 1, the power converter 120 structurally includes a power conversion circuit 122, a high voltage control circuit 124, a low voltage control circuit 126, and a driving circuit 128. The high-voltage side of the power conversion circuit 122 is electrically coupled to the dc generator 110, and the low-voltage side of the power conversion circuit 122 is electrically coupled to the low-voltage energy storage device 150 and the low-voltage load device 170, and is configured to convert the high-voltage dc voltage V1 into a low-voltage dc voltage V2, and output the low-voltage dc voltage V2 to the low-voltage side of the power conversion circuit 122.

In some embodiments, the high voltage control circuit 124 is electrically coupled to the high voltage side for detecting the high voltage dc voltage V1 and outputting the first control signal CT1 accordingly. On the other hand, the low voltage control circuit 126 is electrically coupled to the low voltage side for detecting the low voltage dc voltage V2 and outputting the second control signal CT2 accordingly.

The driving circuit 128 is electrically coupled to the high voltage control circuit 124 and the low voltage control circuit 126, and is used for selectively outputting a driving signal PWM according to the first control signal CT1 or the second control signal CT2 to drive the power conversion circuit 122.

Specifically, the power conversion circuit 122 may be implemented by various switched direct current (DC-DC) conversion circuits. For example, the power conversion circuit 122 may be implemented as a Buck Converter (Buck Converter), a Buck-boost Converter (Buck-boost Converter), or the like. The driving circuit 128 can output the driving signal PWM to switch the switch of the power conversion circuit 122 on and off in a pulse width modulation manner. Therefore, by adjusting the duty cycle of the driving signal PWM, the time length of the complete period during which the switch in the power conversion circuit 122 is turned on can be controlled, and the operation of the power converter 120 can be controlled.

In some embodiments, only one of the high voltage control circuit 124 and the low voltage control circuit 126 is activated at the same time. In other words, when the high voltage control circuit 124 is enabled and outputs the first control signal CT1, the low voltage control circuit 126 is correspondingly disabled. On the other hand, when the low voltage control circuit 126 is enabled and outputs the second control signal CT2, the high voltage control circuit 124 is correspondingly disabled.

It should be noted that in some other embodiments, the driving circuit 128 can also selectively receive the first control signal CT1 or the second control signal CT2 in other manners. Although the embodiment shown in fig. 1 shows that the high voltage control circuit 124 and the low voltage control circuit 126 are coupled to the driving circuit 128 at a common point, in some other embodiments, the power converter 120 may further include a switch for selectively outputting one of the first control signal CT1 and the second control signal CT2 to the driving circuit 128. In some other embodiments, the driving circuit 128 may also receive the first control signal CT1 and the second control signal CT2 through different pins, and determine, by an internal circuit of the driving circuit 128, which duty cycle of the driving signal PWM is to be adjusted. Accordingly, fig. 1 is only one possible implementation of the disclosure, and is not intended to limit the present application.

As shown in fig. 1, the power conversion system 100 can control which of the high voltage control circuit 124 and the low voltage control circuit 126 is turned on or off through the processing circuit 140, and control the voltage level of the high voltage dc voltage V1 or the voltage level of the low voltage dc voltage V2 according to the corresponding command value.

Specifically, the processing circuit 140 is electrically connected to the high voltage control circuit 124 and the low voltage control circuit 126. The processing circuit 140 outputs the HVcmd and LVcmd commands to the hvc 124 and the lv 126, respectively, to control whether the hvc 124 and the lv 126 are enabled.

As shown in fig. 1, the high-side and low-side of the power converter 120 may be coupled to a high-side energy storage device 130 and a low-side energy storage device 150, respectively, for performing necessary power compensation. In some embodiments, the high-side energy storage device 130 and the low-side energy storage device 150 may be implemented by energy storage batteries. For example, the low-side energy storage device 150 is electrically coupled to the low-side load device 170 and the low-side of the power conversion circuit 122. When the low-voltage load device 170 is in light load, the low-voltage side energy storage device 150 may absorb the extra power output by the power converter 120. As such, when the low-voltage load device 170 is heavily loaded or the power converter 120 is not enough to supply the power required by the low-voltage load device 170, the low-voltage energy storage device 150 can output the stored power to the low-voltage load device 170 to maintain the supply and demand balance of the power system.

Similarly, the high-side energy storage device 130 is electrically coupled to the dc generator 110 and the high-side of the power conversion circuit 122. Therefore, the high-side energy storage device 130 can also regulate the power output from the dc generator 110 to the power converter 120 to maintain the high-voltage dc voltage V1 on the high-side stable.

However, when high side energy storage device 130 is decoupled from dc generator 110 or an abnormality occurs, high side energy storage device 130 cannot regulate high voltage dc voltage V1 on the high side. For example, in very low temperature environments. The high voltage battery may fail to operate due to low temperature. In this situation, if the load terminal on the low-voltage side fluctuates sharply, the response of the dc generator 110 is slow, which is not enough to adjust the output power of the generator in time, and it is easy to cause the overvoltage and undervoltage of the high-voltage dc voltage V1 on the high-voltage side, or the overcurrent and overcurrent of the current on the high-voltage side, so that the protection circuit operates accordingly, and the system operation is abnormal, for example, the power supply system stops working.

In order to avoid the above situation, in some embodiments of the present disclosure, when the high-side energy storage device 130 is disconnected from the dc generator 110 or an abnormality occurs, the processing circuit 140 may output a corresponding high-voltage command HVcmd to control the high-voltage control circuit 124 to output the first control signal CT1 to the driving circuit 128 according to the high-voltage command HVcmd, so that the driving circuit 128 controls the high-voltage dc voltage V1 to be stabilized at a corresponding target voltage value. Thus, the activation of the over-voltage or over-current protection mechanism can be avoided.

For the sake of convenience, the cooperative operation of the power converter 120 and the processing circuit 140 will be described with reference to fig. 2A and 2B. Please refer to fig. 2A and fig. 2B. Fig. 2A and 2B are schematic diagrams illustrating an operation of the power converter 120 according to some embodiments of the disclosure.

As shown in fig. 2A and fig. 2B, in some embodiments, the high voltage control circuit 124 includes a voltage divider circuit 220, a compensation circuit 240, a comparison amplifier OP1 and a rectifying element D1. Structurally, the voltage divider circuit 220 is electrically coupled to the high voltage side for dividing the high voltage dc voltage V1 to output the voltage detection signal Vd 1. For example, the voltage divider circuit 220 may include voltage divider resistors R1, R2 in series with each other. By selecting appropriate resistance values of the voltage dividing resistors R1 and R2, the voltage dividing circuit 220 can divide the voltage and output the voltage detection signal Vd1 with an appropriate voltage range for the operation of the subsequent circuit.

In some embodiments, the compensation circuit 240 is electrically coupled between the voltage divider circuit 220 and the driving circuit 128 for receiving the voltage detection signal Vd 1. The first terminal (e.g., the negative terminal) of the comparator OP1 is electrically coupled to the processing circuit 140 for receiving the HVcmd. The second terminal (e.g., positive terminal) of the comparison amplifier OP1 is electrically coupled to the compensation circuit 240. The output terminal of the comparison amplifier OP1 is electrically coupled to the driving circuit 128 through the rectifying device D1 for outputting the first control signal CT 1.

In some embodiments, the rectifying element D1 may be implemented by a diode unit. As shown in fig. 2A and 2B, the anode terminal of the rectifying device D1 is coupled to the driving circuit 128, and the cathode terminal of the rectifying device D1 is coupled to the output terminal of the comparison amplifier OP 1.

As shown in fig. 2A and 2B, the compensation circuit 240 may include a resistor R3 and a resistor R4, but the disclosure is not limited thereto. In other embodiments, the compensation circuit 240 may include resistors and capacitors electrically connected in various forms to form an RC circuit. In the embodiment shown in fig. 2A and 2B, one end of the resistor R3 is electrically coupled to the voltage divider circuit 220, and the other end is electrically coupled to a second end (e.g., a positive end) of the comparison amplifier OP 1. One end of the resistor R4 is electrically coupled to the second end (e.g., positive end) of the comparison amplifier OP1, and the other end is electrically coupled to the output end of the comparison amplifier OP 1.

Similarly, in some embodiments, the low voltage control circuit 126 may also include a corresponding voltage divider circuit 260, a compensation circuit 280 and a comparison amplifier OP 2. Structurally, the voltage dividing circuit 260 is electrically coupled to the low voltage side for dividing the low voltage dc voltage V2 to output the voltage detection signal Vd 2. For example, the voltage divider circuit 260 may include voltage divider resistors R5, R6 in series with each other. By selecting appropriate resistance values of the voltage dividing resistors R5 and R6, the voltage dividing circuit 260 can divide the voltage and output the voltage detection signal Vd2 with an appropriate voltage range for the operation of the subsequent circuit.

In some embodiments, the compensation circuit 280 is electrically coupled between the voltage divider circuit 260 and the driving circuit 128 for receiving the voltage detection signal Vd 2. The first terminal (e.g., positive terminal) of the comparator OP2 is electrically coupled to the processing circuit 140 for receiving the LVcmd command. The second terminal (e.g., the negative terminal) of the comparison amplifier OP2 is electrically coupled to the compensation circuit 280. The output terminal of the comparison amplifier OP2 is electrically coupled to the driving circuit 128 through the rectifying device D2 for outputting the second control signal CT 2.

In some embodiments, the rectifying element D2 may be implemented by a diode unit. As shown in fig. 2A and 2B, the anode terminal of the rectifying device D2 is coupled to the driving circuit 128, and the cathode terminal of the rectifying device D2 is coupled to the output terminal of the comparison amplifier OP 2.

As shown in fig. 2A and 2B, the compensation circuit 280 may include a resistor R7 and a resistor R8, but the disclosure is not limited thereto. Similar to the compensation circuit 240, in other embodiments, the compensation circuit 280 may also include resistors and capacitors electrically connected in various ways to form an RC circuit. In the embodiment shown in fig. 2A and 2B, one end of the resistor R7 is electrically coupled to the voltage divider circuit 260, and the other end is electrically coupled to a second end (e.g., a negative end) of the comparison amplifier OP 2. One end of the resistor R8 is electrically coupled to the second end (e.g., the negative end) of the comparison amplifier OP2, and the other end is electrically coupled to the output end of the comparison amplifier OP 2.

As shown in fig. 2A, in operation, when high-side energy storage device 130 is disconnected from dc generator 110 or an abnormality occurs, processing circuit 140 may output a corresponding high-voltage command HVcmd. At this time, the high voltage control circuit 124 may receive the high voltage command HVcmd from the processing circuit 140 to output the first control signal CT1 to the driving circuit 128 according to the high voltage command HVcmd, so that the driving circuit 128 controls the high voltage dc voltage V1 to be stabilized at a corresponding target voltage value.

Specifically, as shown in FIG. 2A, the high voltage command HVcmd may be first filtered by RC filter circuit 210. The filtered high voltage command HVcmd is input to the negative terminal of the comparator amplifier OP1 as the reference voltage for the high voltage control circuit 124. In this way, the comparison amplifier OP1 outputs the control signal CT1 to the driving circuit 128 in cooperation with the compensation circuit 240 according to the voltage error signals of the positive terminal and the negative terminal.

For example, in some embodiments, the output terminal of the comparison amplifier OP1 is electrically coupled to the Vcomp pin of the driving circuit 128. When the high-voltage direct current voltage V1 is increased due to the reduction of the rear-end load, the voltage detection signal Vd1 fed back by voltage division is also increased. At this time, the voltage value of the Vcomp pin is correspondingly increased, so that the duty cycle of the driving signal PWM outputted from the driving circuit 128 is increased. Therefore, the output power of the power converter 120 is increased accordingly, and the energy can be transmitted to the low-voltage energy storage device 150 at the subsequent stage to control the high-voltage dc voltage V1 not to be further increased to start the over-voltage protection mechanism.

Accordingly, processing circuit 140 outputs a corresponding low voltage command LVdis to control low voltage control circuit 126 to turn off at this time. For example, the low voltage command LVdis can be set to a voltage command corresponding to the maximum output voltage at this time. Thus, the voltage of the Vcomp pin is not affected by the operation of the circuits in the low voltage control circuit 126.

On the other hand, as shown in fig. 2B, in operation, when the high-side energy storage device 130 is operating normally, the processing circuit 140 may output a corresponding low-voltage command LVcmd. At this time, the low voltage control circuit 126 may receive the low voltage command LVcmd from the processing circuit 140 to output the second control signal CT2 to the driving circuit 128 according to the low voltage command LVcmd, so that the driving circuit 128 controls the low voltage dc voltage V2 to be stabilized at the corresponding target voltage value.

Specifically, as shown in FIG. 2B, the low voltage command LVcmd may be first filtered by RC filter circuit 230. The filtered low voltage command LVcmd is input to the positive terminal of the comparator amplifier OP2 as a reference voltage for the low voltage control circuit 126. Thus, the comparison amplifier OP2 outputs the control signal CT2 to the driving circuit 128 in cooperation with the compensation circuit 280 according to the voltage error signals of the positive terminal and the negative terminal.

For example, in some embodiments, the output terminal of the comparison amplifier OP2 is electrically coupled to the Vcomp pin of the driving circuit 128. When the low-voltage dc voltage V2 increases, the voltage detection signal Vd2 fed back by dividing the voltage increases accordingly. Since the fed-back voltage detection signal Vd2 is output to the negative terminal of the comparison amplifier OP2, the voltage value of the Vcomp pin is correspondingly decreased, so that the duty cycle of the driving signal PWM output by the driving circuit 128 is decreased. In this way, the low voltage dc voltage V2 is reduced to control the low voltage dc voltage V2 at a voltage level corresponding to the low voltage command LVcmd.

Accordingly, the processing circuit 140 outputs the high voltage command HVdis at this time to control the high voltage control circuit 124 to turn off according to the corresponding high voltage command HVdis. For example, the high voltage command HVdis may be set to zero at this time. Thus, the voltage of the Vcomp pin is not affected by the operation of the circuits in the high voltage control circuit 124.

In addition, as shown in fig. 2A, since the rectifying elements D1 and D2 are respectively connected to the comparison amplifiers OP1 and OP2 in an opposite manner, the high voltage control circuit 124 and the low voltage control circuit 126 do not interfere with each other during operation, so that abnormal operation occurs. Specifically, when performing the high voltage control, the high voltage control circuit 124 may conduct current from the driving circuit 128 through a current path formed by the rectifying device D1, the voltage dividing circuit 220 and the compensation circuit 240 to match the high voltage command HVcmd to control the voltage value of the Vcomp pin.

Similarly, when performing the low voltage control, the low voltage control circuit 126 may conduct current from the driving circuit 128 through a current path formed by the rectifying device D2, the voltage dividing circuit 260 and the compensation circuit 280 to match the low voltage command LVcmd to control the voltage value of the Vcomp pin. Since the rectifying elements D1 and D2 are connected in reverse, no current path is generated between the high voltage control circuit 124 and the low voltage control circuit 126 to cause interference. It should be noted that in some embodiments, if the high voltage control circuit 124 and the low voltage control circuit 126 are not in common, the output terminals of the comparison amplifiers OP1 and OP2 can also be directly coupled to different pins of the switch or the driving circuit 128 when the driving circuit 128 selects the control mode in other manners without the need of avoiding signal interference through the rectifying devices D1 and D2. Therefore, the circuits shown in fig. 2A and 2B are only examples and are not intended to limit the present disclosure.

In this way, the processing circuit 140 can output the high voltage command and the low voltage command respectively to control whether the high voltage control circuit 124 and the low voltage control circuit 126 are activated.

When the high voltage control circuit 124 is activated, the power converter 120 detects the high voltage dc voltage V1 through the high voltage control circuit 124 and outputs the first control signal CT1 accordingly, so that the driving circuit 128 outputs the driving signal PWM according to the first control signal CT1 to drive the power conversion circuit 122 to control the high voltage dc voltage V1 corresponding to the first control signal CT 1. When the low voltage control circuit 126 is activated, the power converter 120 detects the low voltage dc voltage V2 through the low voltage control circuit 126 and outputs the second control signal CT2 accordingly, so that the driving circuit 128 outputs the driving signal PWM according to the second control signal CT2 to drive the power conversion circuit 122 to control the low voltage dc voltage V2 according to the second control signal CT 2.

Therefore, when the high-voltage side energy storage device 130 is disconnected with the direct current generator 110 or an abnormality occurs, the high-voltage direct current voltage V1 can be stabilized at a corresponding target voltage value, and misoperation of the system caused by the fact that the high-voltage direct current voltage V1 exceeds a safety range is avoided.

Please refer to fig. 3. Fig. 3 is a schematic diagram of a power conversion system 100 according to some other embodiments of the present application. In fig. 3, similar components related to the embodiment of fig. 1 are denoted by the same reference numerals for easy understanding, and the specific principles of the similar components have been described in detail in the previous paragraphs, which are not repeated herein unless necessary for introduction in a cooperative relationship with the components of fig. 3.

As shown in fig. 3, in some embodiments, the power converter 120 may further include an output current control circuit 127, compared to the embodiment of fig. 1. The output current control circuit 127 is electrically coupled to the low voltage side for detecting the output current Io of the power conversion circuit 122 and outputting the third control signal CT3 according to the output current Io. In the present embodiment, the driving circuit 128 is further configured to selectively output the driving signal PWM according to the first control signal CT1, the second control signal CT2 or the third control signal CT 3.

Specifically, in the present embodiment, the processing circuit 140 is further configured to output an output current command Icmd to control whether the output current control circuit 127 is activated. Therefore, the power converter 120 can operate in any one of the high voltage control mode, the low voltage control mode, or the output current control mode according to the control of the processing circuit 140, so as to perform corresponding control according to the current system status.

As described in the previous embodiment, the power converter 120 can operate in the high voltage control mode when the high side energy storage device 130 is disconnected from the dc generator 110 or an abnormality occurs. On the other hand, when the high-side energy storage device 130 is operating normally, the processing circuit 140 may control the power converter 120 to operate in the low-voltage control mode or the output-current control mode according to actual requirements.

For convenience of description, the cooperative operation of the power converter 120 and the processing circuit 140 will be described with reference to fig. 4A to 4C. Please refer to fig. 4A to 4C. Fig. 4A to 4C are schematic diagrams illustrating an operation of the power converter 120 according to some embodiments of the disclosure. In fig. 4A to 4C, similar components related to the embodiments of fig. 2A and 2B are denoted by the same reference numerals for easy understanding, and the specific principles of the similar components have been described in detail in the previous paragraphs, which are not repeated herein unless necessary for introduction due to the cooperative relationship between the components in fig. 4A to 4C.

As shown in fig. 4A to 4C, in some embodiments, the output current control circuit 127 includes a current detection circuit 270, a compensation circuit 290, a comparison amplifier OP3 and a rectifying element D3. The current detection circuit 270 is electrically coupled to the low-voltage side for outputting an output current detection signal Vd3 according to the output current Io. For example, in some embodiments, the current detection circuit 270 may be implemented by a current detection resistor.

The compensation circuit 290 is electrically coupled between the current detection circuit 270 and the driving circuit 128 for receiving the output current detection signal Vd 3. The first terminal of the comparison amplifier OP3 is used for receiving the output current command Icmd, the second terminal of the comparison amplifier OP3 is electrically coupled to the compensation circuit 290, and the output terminal of the comparison amplifier OP3 is electrically coupled to the driving circuit 128 through the rectifying device D3. As described in the previous embodiments, in some embodiments, the rectifying element D3 may be implemented by a diode unit. As shown in fig. 4A to 4C, the anode terminal of the rectifying device D3 is coupled to the driving circuit 128, and the cathode terminal of the rectifying device D3 is coupled to the output terminal of the comparison amplifier OP 3. In other words, the anode terminals of the rectifying elements D1, D2, D3 are coupled to each other to ensure that no current path interference is generated between the output current control circuit 127 and the high voltage control circuit 124 and the low voltage control circuit 126. Since the operation of the rectifying device D3 is similar to that of the rectifying devices D1 and D2 in the previous embodiment, the details thereof are not repeated herein.

As shown in fig. 4A to 4C, the compensation circuit 290 may include a resistor R9 and a resistor R10, but the disclosure is not limited thereto. In other embodiments, the compensation circuit 290 may include resistors and capacitors electrically connected in various forms to form an RC circuit. One end of the resistor R9 is electrically coupled to the current detection circuit 270, and the other end is electrically coupled to a second end (e.g., a negative end) of the comparison amplifier OP 3. One end of the resistor R10 is electrically coupled to the second end (e.g., the negative end) of the comparison amplifier OP3, and the other end is electrically coupled to the output end of the comparison amplifier OP 3.

As shown in fig. 4A, when the high-side energy storage device 130 is disconnected from the dc generator 110 or an abnormality occurs, the power converter 120 may operate in the high-voltage control mode. At this time, the processing circuit 140 outputs the high voltage command HVcmd, so that the comparison amplifier OP1 outputs the control signal CT1 to the driving circuit 128 in cooperation with the compensation circuit 240 according to the voltage error signals of the positive terminal and the negative terminal.

Accordingly, the processing circuit 140 outputs the corresponding low voltage command LVdis and the output current command Idis to control the low voltage control circuit 126 and the output current control circuit 127 to be turned off at this time. For example, the output current command Idis may be set to a current command corresponding to the maximum output current, similar to the low voltage command LVdis. Thus, the voltage of the Vcomp pin is not affected by the operations of the low voltage control circuit 126 and the circuits in the output current control circuit 127. The details of the operation are described in detail in the previous embodiments, and thus are not described herein.

As shown in fig. 4B, the power converter 120 can selectively operate in the low-voltage control mode when the high-side energy storage device 130 operates normally. At this time, the processing circuit 140 outputs the low voltage command LVcmd, so that the comparison amplifier OP2 outputs the control signal CT2 to the driving circuit 128 in cooperation with the compensation circuit 280 according to the voltage error signals of the positive terminal and the negative terminal.

Accordingly, the processing circuit 140 outputs the corresponding high voltage command HVdis and the output current command Idis to control the high voltage control circuit 124 and the output current control circuit 127 to be turned off at this time. The details of the operation are described in detail in the previous embodiments, and thus are not described herein.

As shown in fig. 4C, the power converter 120 can also selectively operate in the output current control mode when the high-side energy storage device 130 is operating normally. At this time, the processing circuit 140 outputs an output current command Icmd, so that the comparison amplifier OP3 outputs the control signal CT3 to the driving circuit 128 in cooperation with the compensation circuit 290 according to the voltage error signals of the positive terminal and the negative terminal.

Therefore, when the output current control circuit 127 is activated, the output current control circuit 127 can output the third control signal CT3 to the driving circuit 128 according to the output current command Icmd, so that the driving circuit 128 controls the output current Io to be stabilized at the target current value corresponding to the output current command Icmd. Since the detailed operation of the output current control circuit 127 is substantially similar to the negative feedback control in the low voltage control circuit 126, the details thereof are not repeated herein.

Accordingly, at this time, the processing circuit 140 outputs the corresponding high voltage command HVdis and the corresponding low voltage command LVdis to control the high voltage control circuit 124 and the low voltage control circuit 126 to be turned off. The details of the operation have been described in detail in the previous embodiments, and thus are not described herein again.

As such, in the embodiment shown in fig. 3 and fig. 4A to fig. 4C, when the high-side energy storage device 130 is disconnected from the dc generator 110 or an abnormality occurs, the processing circuit 140 is configured to output a corresponding high-voltage command, a corresponding low-voltage command and a corresponding output current command to control the high-voltage control circuit 124 to start, and the low-voltage control circuit 126 and the output current control circuit 127 to turn off, so as to stabilize the high-voltage dc voltage V1 at a corresponding target voltage value.

When the high-side energy storage device 130 operates normally, the processing circuit 140 is configured to output a corresponding high-voltage command, a corresponding low-voltage command, and an output current command, so as to control one of the low-voltage control circuit 126 and the output current control circuit 127 to start, so as to stabilize the low-voltage dc voltage V2 at a corresponding target voltage value, or stabilize the output current Io at a corresponding target current value.

Please refer to fig. 5. Fig. 5 is a flowchart illustrating a method 900 for controlling the power converter 120 according to some embodiments of the disclosure. For convenience and clarity of illustration, the following control method 900 of the power converter 120 is described with reference to the embodiments shown in fig. 1 to 4C, but not limited thereto, and those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application. As shown in fig. 5, the control method 900 of the power converter 120 includes steps S910, S920, S930, S940 and S950.

First, in step S910, the high-voltage dc voltage V1 on the high-voltage side is converted into a low-voltage dc voltage V2 by the power conversion circuit 122 and output to the low-voltage side.

In step S920, the processing circuit 140 selectively activates the high voltage control circuit 124 electrically coupled to the high voltage side or the low voltage control circuit 126 electrically coupled to the low voltage side.

For example, in some embodiments, when the high-side energy storage device 130 is disconnected from the dc generator 110 or an abnormality occurs, the processing circuit 140 may output a corresponding high-voltage command HVcmd to the high-voltage control circuit 124 to activate the high-voltage control circuit 124.

When the high voltage control circuit 124 is activated, the process proceeds to step S930. In step S930, the high-voltage dc voltage V1 is detected by the high-voltage control circuit 124 and a first control signal CT1 is outputted accordingly. For example, the high voltage control circuit 124 may output the first control signal CT1 to the driving circuit 128 according to the detected voltage detection signal Vd1 and the high voltage command HVcmd.

When the low voltage control circuit 126 is activated, the process proceeds to step S940. In step S940, the low voltage dc voltage V2 is detected by the low voltage control circuit 126 and the second control signal CT2 is outputted accordingly. For example, the low voltage control circuit 126 may output the second control signal CT2 to the driving circuit 128 according to the detected voltage detection signal Vd2 and the low voltage command LVcmd.

Finally, in step S950, the driving circuit 128 outputs the driving signal PWM to drive the power conversion circuit 122 according to the first control signal CT1 or the second control signal CT2, so as to control the high-voltage dc voltage V1 corresponding to the first control signal CT1 or control the low-voltage dc voltage V2 corresponding to the second control signal CT 2.

In other words, when the high voltage control circuit 124 is activated, the driving circuit 128 controls the high voltage dc voltage V1 to be stabilized at the corresponding target voltage value according to the first control signal CT1 in step S950. When the low voltage control circuit 126 is activated, the driving circuit 128 may control the low voltage dc voltage V2 to be stabilized at a corresponding target voltage value according to the second control signal CT2 in step S950.

It is noted that, in some embodiments, the step S920 may further include selectively activating, by the processing circuit 140, the high voltage control circuit 124 electrically coupled to the high voltage side, the low voltage control circuit 126 electrically coupled to the low voltage side, or the output current control circuit 127 electrically coupled to the low voltage side. When the output current control circuit 127 is activated, the output current Io is detected by the output current control circuit 127, and the third control signal CT3 is outputted accordingly. In step S950, the driving circuit 128 further outputs the driving signal PWM according to the third control signal CT3 to drive the power conversion circuit 122, so as to control the output current Io according to the third control signal CT 3. The details of which are described in detail in the previous paragraphs, and thus are not described herein again.

The above includes exemplary steps. However, these steps need not be performed sequentially. The steps mentioned in the present embodiment can be performed simultaneously or partially simultaneously, except for the specific order mentioned above, the order before and after the steps can be adjusted according to the actual requirement.

Those skilled in the art can directly understand how to implement the control method 900 based on the power conversion system 100 in the above-mentioned various embodiments, and therefore the detailed description is omitted here.

In summary, in the embodiments of the disclosure, when the high-side energy storage device 130 is disconnected from the dc generator 110 or an abnormality occurs, the processing circuit 140 outputs the corresponding high-voltage command HVcmd to control the high-voltage control circuit 124 to output the first control signal CT1 to the driving circuit 128 according to the high-voltage command HVcmd, so that the driving circuit 128 controls the high-voltage dc voltage V1 to be stabilized at the corresponding target voltage value, and the over-voltage or over-current protection mechanism can be prevented from being activated. Therefore, under the condition that the high-voltage battery fails abnormally or the high-voltage battery cannot work due to an extremely low temperature environment, the power converter 120 can actively stabilize the high-voltage power supply, so as to ensure that the electric vehicle or the oil-electric hybrid vehicle can run normally, and further improve the system reliability.

Although the present disclosure has been described with reference to the above embodiments, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the disclosure, and therefore, the scope of the disclosure should be determined by that defined in the appended claims.

Claims

1. A power converter, comprising:

the power supply conversion circuit is used for receiving a high-voltage direct-current voltage from a high-voltage side and converting the high-voltage direct-current voltage into a low-voltage direct-current voltage to be output to a low-voltage side;

the high-voltage control circuit is electrically coupled to the high-voltage side and used for detecting the high-voltage direct current voltage and outputting a first control signal according to the high-voltage direct current voltage;

the low-voltage control circuit is electrically coupled to the low-voltage side and used for detecting the low-voltage direct-current voltage and outputting a second control signal according to the low-voltage direct-current voltage; and

a driving circuit for selectively outputting a driving signal to drive the power conversion circuit according to the first control signal or the second control signal,

when a high-voltage side energy storage device coupled to the high-voltage side of the power conversion circuit is disconnected from a direct current generator or is abnormal, the low-voltage control circuit is turned off, and the high-voltage control circuit is turned on to generate the first control signal to the driving circuit so as to stabilize the high-voltage direct current voltage at a corresponding target voltage value.

2. The power converter of claim 1, wherein the high voltage control circuit is further configured to receive a high voltage command from a processing circuit, and output the first control signal to the driving circuit according to the high voltage command, so that the driving circuit controls the high voltage dc voltage to be stabilized at a corresponding target voltage value.

3. The power converter of claim 2, wherein the high voltage control circuit comprises:

a first voltage dividing circuit for dividing the high voltage DC voltage to output a first voltage detection signal;

a first compensation circuit electrically coupled between the first voltage divider circuit and the driving circuit for receiving the first voltage detection signal; and

a first terminal of the first comparison amplifier is used for receiving the high voltage command, a second terminal of the first comparison amplifier is electrically coupled to the first compensation circuit, and an output terminal of the first comparison amplifier is electrically coupled to the driving circuit.

4. The power converter as claimed in claim 1, wherein the low voltage control circuit is further configured to receive a low voltage command from a processing circuit, and output the second control signal to the driving circuit according to the low voltage command, so that the driving circuit controls the low voltage dc voltage to be stabilized at a corresponding target voltage value.

5. The power converter of claim 4, wherein the low voltage control circuit comprises:

a second voltage dividing circuit for dividing the low voltage DC voltage to output a second voltage detection signal;

a second compensation circuit, electrically coupled between the second voltage divider circuit and the driving circuit, for receiving the second voltage detection signal; and

a second comparison amplifier, a first end of the second comparison amplifier is used for receiving the low voltage command, a second end of the second comparison amplifier is electrically coupled to the second compensation circuit, and an output end of the second comparison amplifier is electrically coupled to the driving circuit.

6. The power converter of claim 1, further comprising:

the output current control circuit is electrically coupled to the low-voltage side and used for detecting an output current of the power supply conversion circuit, receiving an output current command from a processing circuit and outputting a third control signal according to the output current and the output current command;

the driving circuit is further configured to selectively output the driving signal according to the first control signal, the second control signal, or the third control signal.

7. The power converter of claim 6, wherein the output current control circuit comprises:

a current detection circuit for outputting an output current detection signal according to the output current;

a third compensation circuit, electrically coupled between the current detection circuit and the driving circuit, for receiving the output current detection signal; and

a third comparison amplifier, a first end of the third comparison amplifier is used for receiving the output current command, a second end of the third comparison amplifier is electrically coupled to the third compensation circuit, and an output end of the third comparison amplifier is electrically coupled to the driving circuit.

8. A power conversion system, comprising:

the direct current generator is used for outputting a high-voltage direct current voltage;

a power conversion circuit, a high-voltage side of which is electrically coupled to the dc generator for converting the high-voltage dc voltage into a low-voltage dc voltage and outputting the low-voltage dc voltage to a low-voltage side of the power conversion circuit;

the high-voltage control circuit is electrically coupled to the high-voltage side and used for detecting the high-voltage direct current voltage and correspondingly outputting a first control signal;

the low-voltage control circuit is electrically coupled to the low-voltage side and used for detecting the low-voltage direct-current voltage and correspondingly outputting a second control signal;

the processing circuit is used for respectively outputting a high-voltage command and a low-voltage command to the high-voltage control circuit and the low-voltage control circuit so as to control whether the high-voltage control circuit and the low-voltage control circuit are started or not; and

the high-voltage side energy storage device is electrically coupled to the direct-current generator and the high-voltage side of the power conversion circuit;

when the high-voltage side energy storage device is disconnected with the direct-current generator or abnormal conditions occur, the processing circuit is used for outputting the corresponding high-voltage command to control the high-voltage control circuit to output the first control signal to the driving circuit according to the high-voltage command, so that the driving circuit controls the high-voltage direct-current voltage to be stabilized at a corresponding target voltage value.

9. The power conversion system of claim 8, wherein the high voltage control circuit comprises:

10. The power conversion system of claim 8, wherein the low voltage control circuit comprises:

11. The power conversion system of claim 8, wherein the processing circuit is further configured to output the corresponding low-voltage command to control the low-voltage control circuit to turn off when the high-side energy storage device is disconnected from the dc generator or an abnormality occurs.

12. The power conversion system of claim 8, further comprising:

the output current control circuit is electrically coupled to the low-voltage side and used for detecting an output current of the power supply conversion circuit and outputting a third control signal according to the output current;

the processing circuit is used for outputting an output current command to control whether the output current control circuit is started or not, and the driving circuit is further used for selectively outputting the driving signal according to the first control signal, the second control signal or the third control signal.

13. The power conversion system of claim 12, wherein the processing circuit is configured to output the corresponding high voltage command, the corresponding low voltage command, and the corresponding output current command to control one of the low voltage control circuit and the output current control circuit to start when the high side energy storage device is operating normally.

14. The power conversion system of claim 12, wherein when the low voltage control circuit is activated, the low voltage control circuit is configured to output the second control signal to the driving circuit according to the low voltage command, so that the driving circuit controls the low voltage dc voltage to be stabilized at a corresponding target voltage value, and the output current control circuit is deactivated according to the corresponding output current command.

15. The power conversion system of claim 12, wherein when the output current control circuit is activated, the output current control circuit is configured to output the third control signal to the driving circuit according to the output current command, such that the driving circuit controls the output current to be stabilized at a corresponding target current value, and the low voltage control circuit is deactivated according to the corresponding low voltage command.

16. The power conversion system of claim 12, wherein the high voltage control circuit is turned off according to the corresponding high voltage command when the high side energy storage device is operating normally.

17. The power conversion system of claim 12, wherein the output current control circuit comprises:

18. A control method for a power converter according to any one of claims 1-7, comprising:

a power conversion circuit converts a high-voltage DC voltage at a high-voltage side into a low-voltage DC voltage and outputs the low-voltage DC voltage to a low-voltage side;

selectively activating, by a processing circuit, a high voltage control circuit electrically coupled to the high voltage side or a low voltage control circuit electrically coupled to the low voltage side;

when the high-voltage control circuit is started, detecting the high-voltage direct current voltage and correspondingly outputting a first control signal through the high-voltage control circuit;

when the low-voltage control circuit is started, detecting the low-voltage direct current voltage and correspondingly outputting a second control signal through the low-voltage control circuit; and

a driving circuit outputs a driving signal to drive the power conversion circuit according to the first control signal or the second control signal, so as to control the high-voltage DC voltage corresponding to the first control signal or control the low-voltage DC voltage corresponding to the second control signal.

19. The method of controlling a power converter of claim 18, further comprising:

when a high-voltage side energy storage device coupled to the high-voltage side is disconnected with a direct current generator or is abnormal, outputting a corresponding high-voltage command to the high-voltage control circuit through the processing circuit;

outputting the first control signal to the driving circuit by the high-voltage control circuit according to the high-voltage command; and

the driving circuit controls the high-voltage direct current voltage to be stabilized at a corresponding target voltage value according to the first control signal.