A control circuit and method for bidirectional DCDC power supply charging and discharging high-speed switching

Abstract

The application is suitable for the field of energy storage power supply technology improvement, and provides a control circuit and method for high-speed switching of bidirectional DCDC power supply charging and discharging, which acquires the output current of the bidirectional DCDC power supply in real time through an output positive and negative current sampling detection circuit and converts the output current into a differential voltage signal; an output current detection comparison circuit compares the signal and outputs a high / low level signal corresponding to the current direction; a master control unit digital control processor DSC1 controls the power supply to switch between the discharging and charging states immediately according to the jump of the level signal. The application uses simple differential amplification and high-speed comparison circuit to realize microsecond-level fast charging and discharging state following, solves the switching delay problem caused by the dependence of the prior art on communication or voltage loop, and has the advantages of fast response speed, high reliability, low cost, and wide application scenarios.

Description

Technical Field

[0001] This invention belongs to the field of energy storage power technology improvement, and in particular relates to a control circuit and method for high-speed switching of bidirectional DC-DC power charging and discharging. Background Technology

[0002] Currently, the industry typically uses communication to transmit charging or discharging commands for switching in bidirectional DC-DC power supply technology, or hardware buttons or similar function switches to achieve switching. Some methods use current sensors to detect positive and negative output current, but this requires additional current sensors and positive and negative power supplies. Furthermore, conventional current sensors have significant current delays, and high-current sensors are inherently expensive. Voltage loops are also used for switching, but these have significant hysteresis and are prone to malfunctions during dynamic switching. In applications where low-voltage lithium iron phosphate batteries combined with a bidirectional DC-DC power supply with a BMS replace lead-acid batteries used in various small electric vehicles, the lack of communication between the battery and the vehicle's motor control necessitates a higher requirement for the switching response speed of the bidirectional DC-DC power supply. Figure 1 As shown, there are three main reasons for this: first, the motor requires a large instantaneous current to start; second, the acceleration, deceleration, and braking states of the trolley during operation are quite unpredictable; and third, the maximum current fed back by the motor varies between different trolleys, and the specific current magnitude under different conditions is also unclear. For example, during operation, acceleration or climbing may require increased output from the bidirectional DC-DC converter, followed by deceleration or braking requiring immediate feedback of power from the bidirectional DC-DC converter. Then, acceleration or further climbing may be needed, requiring the bidirectional power supply to provide sufficient power to the trolley motor. In these situations, the bidirectional DC-DC converter needs to be able to quickly switch between discharging (powering the motor from the lithium battery via the bidirectional DC-DC converter) and charging (charging the lithium battery via the bidirectional DC-DC converter). Otherwise, it may lead to loss of control during operation, or excessively long switching delays during high current feedback from the motor may cause the bidirectional DC-DC converter output voltage to be charged too high, leading to reliability issues or abnormal input or feedback voltages of the trolley motor. Summary of the Invention

[0003] The purpose of this invention is to provide a control circuit and method for high-speed switching of bidirectional DC-DC power supply charging and discharging, in order to solve the above-mentioned technical problems.

[0004] The present invention is implemented as follows: a control circuit for high-speed switching of bidirectional DC-DC power supply charging and discharging, the control circuit including an output positive and negative current sampling and detection circuit, an output current detection and comparison circuit, and a main control unit digital control processor DSC1;

[0005] The output positive and negative current sampling and detection circuit is used to sample the output current of the bidirectional DC-DC power supply and convert the current signal into a differential voltage signal.

[0006] The output current detection and comparison circuit is connected to the output positive and negative current sampling and detection circuit, and is used to receive the differential voltage signal and compare it, and output a high and low level signal Vout_CP_D2C corresponding to the current direction;

[0007] The main control unit digital control processor DSC1 is connected to the output current detection and comparison circuit, and is used to receive the high and low level signal Vout_CP_D2C, and control the bidirectional DC-DC power supply to switch between the discharge state and the charging state according to the high and low level changes of the high and low level signal Vout_CP_D2C.

[0008] Specifically, when the output current is positive, the high / low level signal Vout_CP_D2C output by the output current detection and comparison circuit is high; when the output current is negative, the high / low level signal Vout_CP_D2C output by the output current detection and comparison circuit is low.

[0009] A further technical solution of the present invention is: the output positive and negative current sampling and detection circuit includes a sampling resistor and a differential amplifier circuit;

[0010] The sampling resistor is connected in series between the negative output terminal of the bidirectional DC-DC power supply and the working ground.

[0011] The differential amplifier circuit is connected across the sampling resistor to detect the voltage drop across the sampling resistor and output the differential voltage signal.

[0012] The differential amplifier circuit includes a pair of bipolar transistors, two pull-up resistors, and a filter capacitor.

[0013] The two emitters of the bipolar junction transistor pair are respectively connected to the two ends of the sampling resistor, and the two collectors of the bipolar junction transistor pair are respectively connected to the power supply VCC and the filter capacitor through the two pull-up resistors, and respectively output the two components of the differential voltage signal.

[0014] A further technical solution of the present invention is: the output current detection and comparison circuit includes a differential comparator;

[0015] The non-inverting input and inverting input of the differential comparator receive two components of the differential voltage signal, namely input signal VO_ISE_2 and input signal VO_ISE_1, respectively, and compare their voltage magnitudes.

[0016] When the input signal VO_ISE_2 is greater than the input signal VO_ISE_1, the high / low level signal Vout_CP_D2C output by the differential comparator is high.

[0017] When the input signal VO_ISE_2 is less than the input signal VO_ISE_1, the high / low level signal Vout_CP_D2C output by the differential comparator is low.

[0018] The differential comparator outputs the high and low level signals Vout_CP_D2C to the main control unit digital control processor DSC1;

[0019] The differential comparator is a high-speed push-pull output comparator or an OC gate output comparator.

[0020] A further technical solution of the present invention is as follows: the main control unit digital control processor DSC1 judges the input high and low level signals Vout_CP_D2C. When the high and low level signal Vout_CP_D2C is high, the output current is positive; when the high and low level signal Vout_CP_D2C is low, the output current is negative; when the high and low level signal Vout_CP_D2C changes from high to low, the bidirectional DC-DC power supply immediately switches from the discharging state to the charging state; when the high and low level signal Vout_CP_D2C changes from low to high, the bidirectional DC-DC power supply immediately switches from the charging state to the discharging state.

[0021] A further technical solution of the present invention is as follows: the output positive and negative current sampling and detection circuit includes an output filter electrolytic capacitor C1, a sampling resistor R3, a bipolar transistor pair VT1, a pull-up resistor R1, a pull-up resistor R2, and a filter capacitor C2; one end of the output filter electrolytic capacitor C1 is connected to the positive output terminal Vout_P of the bidirectional DC-DC power supply, and the other end of the output filter electrolytic capacitor C1 is connected to the working ground GND1; one end of the sampling resistor R3 is connected to the working ground GND1, and the other end of the sampling resistor R3 is connected to pin 3 of the bipolar transistor pair VT1 and the negative output terminal Vout_P of the bidirectional DC-DC power supply, respectively. t_N, pin 4 of the bipolar junction transistor pair VT1 is connected to the working ground GND1. Pin 1 of the bipolar junction transistor pair VT1 is connected to one end of the pull-up resistor R1 to form an input signal VO_ISE_1, which is sent to the output current detection and comparison circuit. Pin 2 of the bipolar junction transistor pair VT1 is connected to one end of the pull-up resistor R2 to form an input signal VO_ISE_2, which is sent to the output current detection and comparison circuit. The other ends of the pull-up resistor R1 and the other ends of the pull-up resistor R2 are connected to the power supply VCC. One end of the filter capacitor C2 is connected to the working ground GND1, and the other end of the filter capacitor C2 is connected to the power supply VCC.

[0022] A further technical solution of the present invention is as follows: the output current detection and comparison circuit includes resistor R4, resistor R5, capacitor C4, capacitor C5, differential comparator D2, resistor R6, capacitor C6, and capacitor C3; the input signal VO_ISE_2 is connected to one end of resistor R4, the other end of resistor R4 is connected to one end of capacitor C4 and the non-inverting input terminal of differential comparator D2, the other end of capacitor C4 is connected to ground GND1, the input signal VO_ISE_1 is connected to one end of resistor R5, the other end of resistor R5 is connected to one end of capacitor C5 and the inverting input terminal of differential comparator D2, and the capacitor... The other end of C5 is connected to the working ground GND1. Pin 2 of the differential comparator D2 is connected to the working ground GND1. Pin 5 of the differential comparator D2 and one end of the capacitor C6 are respectively connected to the power supply VCC. The other end of the capacitor C6 is connected to the working ground GND1. The output terminal of the differential comparator D2 is connected to one end of the resistor R6. The other end of the resistor R6 is connected to one end of the capacitor C3 to form a high / low level output signal Vout_CP_D2C. The high / low level signal Vout_CP_D2C is output to the main control unit digital control processor DSC1. The other end of the capacitor C3 is connected to the working ground GND1.

[0023] A further technical solution of the present invention is that the overall response time from the change of the output current direction of the bidirectional DC-DC power supply to the receipt of the corresponding high / low level signal Vout_CP_D2C change by the main control unit digital control processor DSC1 is less than or equal to 2 microseconds.

[0024] Another objective of this invention is to provide a control method for high-speed switching of bidirectional DC-DC power supply charging and discharging, applied to a control circuit for high-speed switching of bidirectional DC-DC power supply charging and discharging, the control method comprising the following steps:

[0025] S1. Real-time sampling of the output current of the bidirectional DC-DC power supply;

[0026] S2. The current signal is converted into the corresponding differential voltage signal through the constructed differential amplifier circuit, namely the input signal VO_ISE_1 and the input signal VO_ISE_2.

[0027] S3. Compare the input signal VO_ISE_1 and the input signal VO_ISE_2, and generate a high-low level signal Vout_CP_D2C corresponding to the current direction. The high-low level signal Vout_CP_D2C generated when the output current is positive is high-level, and the high-low level signal Vout_CP_D2C generated when the output current is negative is low-level.

[0028] S4. The main control unit digital control processor DSC1 controls the bidirectional DC-DC power supply to switch from the discharging state to the charging state or from the charging state to the discharging state according to the level change of the high and low level signal Vout_CP_D2C.

[0029] A further technical solution of the present invention is: when a positive current is detected in the discharge state in step S1, the output input signal VO_ISE_2 is greater than the input signal VO_ISE_1; when a negative current is detected in the charging state, the output input signal VO_ISE_2 is less than the input signal VO_ISE_1.

[0030] A further technical solution of the present invention is: the control logic of the main control unit digital control processor DSC1 is as follows:

[0031] When the high / low level signal Vout_CP_D2C is high, the output current is determined to be positive, and the bidirectional DC-DC power supply is in the discharge state.

[0032] When the high / low level signal Vout_CP_D2C is low, the output current is determined to be negative, and the bidirectional DC-DC power supply is in a charging state.

[0033] When the high-level signal Vout_CP_D2C changes from high to low, the bidirectional DC-DC power supply immediately switches from the discharging state to the charging state.

[0034] When the high / low level signal Vout_CP_D2C changes from low level to high level, the bidirectional DC-DC power supply immediately switches from charging state to discharging state;

[0035] The total response time for switching from the charging / discharging current to the high / low level signal Vout_CP_D2C to form the corresponding high / low level is ≤2 microseconds; if a high-speed push-pull output comparator or an OC gate output comparator is selected, the total response time is ≤900 nanoseconds; in step S1, the output current is sampled through the sampling resistor R3, and the resistance value of the sampling resistor R3 is selected according to the rated detection current. When the rated detection current is ±200A, the resistance value of the sampling resistor R3 is on the order of 0.1 milliohms.

[0036] The beneficial effects of this invention are: the control circuit has high reliability: it detects the positive and negative current values ​​in real time during the switching process, and outputs the positive and negative differential voltage values ​​corresponding to the positive and negative currents. It does not need to be linear and accurate. It only needs the positive and negative differential voltage values ​​as the input signals of the comparator to form the corresponding high and low level signals. The positive and negative current sampling and detection circuit is composed of a pair of bipolar transistors with the bases of the two transistors connected. It has current-type amplification and strong anti-interference ability.

[0037] The switching speed is very fast. When switching between charging and discharging current, the response time of the output positive and negative current sampling and detection circuit is about 100 nanoseconds. If the comparator in the output current detection and comparison circuit is selected as a high-speed push-pull output or an open-source gate output, the response time is generally a few nanoseconds to tens of nanoseconds. Because RC filtering delay is required to filter out the power frequency, the total response time from the switching of the charging and discharging current to the signal Vout_CP_D2C forming the corresponding low and high level is about 900 nanoseconds. If a normal comparator is selected, the total response time from the switching of the charging and discharging current to the signal Vout_CP_D2C forming the corresponding low and high level is generally about 2 microseconds.

[0038] Wide range of applications: The switching control strategy of this bidirectional DC-DC power supply is suitable for scenarios where there is no communication with the load to transmit charging and discharging switching commands, as well as scenarios where there is communication function. Even in the case of communication interference and interruption, it can ensure that the bidirectional DC-DC power supply can follow the dynamic switching of charging current at high speed to make corresponding charging and discharging switching, ensuring the stable operation of the bidirectional DC-DC power supply and associated equipment.

[0039] Low cost: Compared to conventional bidirectional DC-DC power supplies, the main hardware cost increases is the addition of a transistor pair and a comparator; due to the high response speed, the capacitance of the electrolytic capacitor at the output end, which delays the output voltage change, can be significantly reduced, thus appropriately lowering the cost.

[0040] The detection switching current is relatively large and easy to implement: the circuit is simple, the detection is easy to implement, and the detection switching current is large. For example, if the rated current is ±200A, the sampling resistor is 0.1 milliohm. Attached Figure Description

[0041] Figure 1 This is a block diagram of existing technology principles.

[0042] Figure 2 This is a block diagram of the control circuit for high-speed switching of bidirectional DC-DC power supply charging and discharging provided in an embodiment of the present invention.

[0043] Figure 3 This is an electrical schematic diagram of the control circuit for high-speed switching of bidirectional DC-DC power supply charging and discharging provided in an embodiment of the present invention. Detailed Implementation

[0044] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0045] To address the problems in the background technology, this invention proposes a control circuit and method for high-speed switching of bidirectional DC-DC power supply charging and discharging. A differential amplifier circuit continuously monitors the output current of the bidirectional power supply to the motor. When the current detected is positive during discharging, the differential amplifier circuit outputs a positive differential voltage signal, which is sent to the output current detection and comparison circuit, resulting in a high-level output signal. When the current detected is negative during charging, the differential amplifier circuit outputs a negative differential voltage signal, which is also sent to the output current detection and comparison circuit, resulting in a low-level output signal. The output signal from the output current detection and comparison circuit is then sent to the main control unit's digital control processor (DSC1) for judgment and processing. When a change between positive and negative current is detected in the bidirectional DC-DC output current, the DSC1 correspondingly switches the output signal from the output current detection and comparison circuit between high and low levels, and the DSC1 immediately performs the corresponding discharging and charging switch.

[0046] To better achieve the above objectives, the principle block diagram of the technical solution of this invention is as follows: Figure 2 As shown, the basic functional circuits and corresponding controls of the bidirectional DC-DC power supply itself, such as the internal auxiliary power supply, bidirectional DC-DC power conversion circuit, and other protection and control circuits, will not be further elaborated here. The technical solution of this application will be specifically described as follows:

[0047] like Figure 2 , Figure 3 As shown, a control circuit for high-speed switching of bidirectional DC-DC power supply charging and discharging includes an output positive and negative current sampling and detection circuit, an output current detection and comparison circuit, and a main control unit digital control processor DSC1.

[0048] One end of the output filter electrolytic capacitor C1 of the output positive and negative current sampling and detection circuit is connected to the positive output terminal Vout_P of the bidirectional DC-DC power supply, and the other end of the output filter electrolytic capacitor C1 is connected to the working ground GND1; one end of the output positive and negative current sampling resistor R3 is connected to the working ground GND1, and the other end of the sampling resistor R3 is connected to pin 3 of the bipolar transistor pair VT1 and the negative output terminal Vout_N of the bidirectional DC-DC power supply; pin 4 of the bipolar transistor pair VT1 is connected to the working ground GND1; pin 1 of the bipolar transistor pair VT1 is connected to one end of the pull-up resistor R1 to form an input signal VO_ISE_1 sent to the output current detection and comparison circuit; pin 2 of the bipolar transistor pair VT1 is connected to one end of the pull-up resistor R2 to form an input signal VO_ISE_2 sent to the output current detection and comparison circuit; the other ends of the pull-up resistor R1 and the other ends of the pull-up resistor R2 are connected to the power supply VCC; one end of the filter capacitor C2 is connected to the working ground GND1, and the other end of the filter capacitor C2 is connected to the power supply VCC.

[0049] The output current detection and comparison circuit compares the voltage magnitudes of the input signals VO_ISE_2 and VO_ISE_1. When the input signal VO_ISE_2 is greater than or equal to the input signal VO_ISE_1, the output high / low level signal Vout_CP_D2C is high; when the input signal VO_ISE_2 is less than the input signal VO_ISE_1, the output high / low level signal Vout_CP_D2C is low. This high / low level signal Vout_CP_D2C is sent to the main control unit digital control processor DSC1.

[0050] In the output current detection and comparison circuit, the input signal VO_ISE_2 is connected to one end of resistor R4. The other end of resistor R4 is connected to one end of capacitor C4 and the non-inverting input of differential comparator D2. The other end of capacitor C4 is connected to ground GND1. The input signal VO_ISE_1 is connected to one end of resistor R5. The other end of resistor R5 is connected to one end of capacitor C5 and the inverting input of differential comparator D2. The other end of capacitor C5 is connected to ground GND1. Pin 2 of differential comparator D2 is connected to ground GND1. Pin 5 of differential comparator D2 and one end of capacitor C6 are connected to the power supply VCC. The other end of capacitor C6 is connected to ground GND1. The push-pull output of differential comparator D2 is connected to one end of resistor R6. The other end of resistor R6 is connected to one end of capacitor C3 to form the output high / low level signal Vout_CP_D2C. The high / low level signal Vout_CP_D2C is sent to the main control unit digital control processor DSC1. The other end of capacitor C3 is connected to ground GND1.

[0051] The main control unit, digital control processor DSC1, judges the input high and low level signals Vout_CP_D2C. When the high and low level signals Vout_CP_D2C are high, the output current is positive; when the high and low level signals Vout_CP_D2C are low, the output current is negative; when the high and low level signals Vout_CP_D2C change from high to low, the bidirectional DC-DC power supply immediately switches from the discharging state to the charging state, and when the high and low level signals Vout_CP_D2C change from low to high, the bidirectional DC-DC power supply immediately switches from the charging state to the discharging state.

[0052] The working principle and control method of the technical solution of the present invention are described in detail below: The basic functional circuits and corresponding controls of the bidirectional DC-DC power supply itself, such as the internal auxiliary power supply, bidirectional DC-DC power conversion circuit, and other protection and control circuits, are not further described here.

[0053] In the output positive and negative current sampling circuit, sampling resistor R3 samples the positive current of the charger's discharge and the negative current of its charge. This sampling resistor R3 should be placed to the right of the output filter electrolytic capacitor C1 to immediately detect the negative charging current when there is a negative charging current at the output terminal during the discharge state. A differential circuit composed of bipolar transistor pair VT1, pull-up resistor R1, and pull-up resistor R2 detects the current flowing through sampling resistor R3. The red arrow indicates a positive current, meaning the discharge current is positive and the charging current is negative. When a positive current is detected during the discharge state, two voltage input signals, VO_ISE_2 and VO_ISE_1, are output, with input signal VO_ISE_2 being greater than input signal VO_ISE_1. When a positive current is detected during the charging state... When the current is negative, two voltage input signals VO_ISE_2 and VO_ISE_1 are output, with VO_ISE_2 being less than VO_ISE_1. When the switching current is large (e.g., hundreds of amperes), the value of the sampling resistor R3 will be smaller, and the peak values ​​of the positive and negative voltages on the sampling resistor R3 are generally much less than 1V. If the peak voltage exceeds the allowable reverse voltage of the two BE junctions of the bipolar transistor pair VT1, it is necessary to consider connecting a forward diode (two independent diodes packaged together) in series in the forward voltage drop direction of each of the two BE junctions of the bipolar transistor pair VT1 to improve the ability to resist reverse voltage stress. Input signals VO_ISE_2 and VO_ISE_1 are sent to the output current detection and comparison circuit.

[0054] The output current detection and comparison circuit performs a differential comparison on the input signals VO_ISE_2 and VO_ISE_1. The input signals VO_ISE_2 and VO_ISE_1 serve as the non-inverting and inverting input signals of the differential comparator D2 in the output current detection circuit, respectively, and output high and low level signals Vout_CP_D2C. When the current flowing through the sampling resistor R3 is positive or zero, the high and low level signal Vout_CP_D2C is high; when the current flowing through the sampling resistor R3 is negative, the high and low level signal Vout_CP_D2C is low.

[0055] The sampling resistor R3 has a resistance of 1mΩ, and the switching current flowing through it is +0.1A and -0.1A. The differential comparator is a high-speed comparator. The simulation waveform of the response delay of the high and low level signals Vout_CP_D2C with the switching current shows that when the current flowing through the sampling resistor R3 switches from +0.1A to -0.1A, the response time of the high and low level signals Vout_CP_D2C from high to low level is delayed by about 800ns. When the current flowing through the sampling resistor R3 switches from -0.1A to +0.1A, the response time of the high and low level signals Vout_CP_D2C from low to high level is delayed by about 200ns. It can be seen that the detection switching speed is very fast.

[0056] The high / low level signal Vout_CP_D2C is sent to the main control unit digital control processor DSC1. When the main control unit digital control processor DSC1 detects that the high / low level signal Vout_CP_D2C changes from high level to low level, the bidirectional DC-DC power supply immediately switches its working state from the discharging state to the charging state. When the main control unit digital control processor DSC1 detects that the high / low level signal Vout_CP_D2C changes from low level to high level, the bidirectional DC-DC power supply immediately switches its working state from the charging state to the discharging state.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A control circuit for high-speed switching of bidirectional DC-DC power supply charging and discharging, characterized in that, The control circuit includes an output positive and negative current sampling and detection circuit, an output current detection and comparison circuit, and a main control unit digital control processor (DSC1). The output positive and negative current sampling and detection circuit is used to sample the output current of the bidirectional DC-DC power supply and convert the current signal into a differential voltage signal. The output current detection and comparison circuit is connected to the output positive and negative current sampling and detection circuit, and is used to receive the differential voltage signal and compare it, and output a high and low level signal Vout_CP_D2C corresponding to the current direction; The main control unit digital control processor DSC1 is connected to the output current detection and comparison circuit, and is used to receive the high and low level signal Vout_CP_D2C, and control the bidirectional DC-DC power supply to switch between the discharge state and the charging state according to the high and low level changes of the high and low level signal Vout_CP_D2C. Specifically, when the output current is positive, the high / low level signal Vout_CP_D2C output by the output current detection and comparison circuit is high; when the output current is negative, the high / low level signal Vout_CP_D2C output by the output current detection and comparison circuit is low. The output positive and negative current sampling and detection circuit includes a sampling resistor and a differential amplifier circuit; The sampling resistor is connected in series between the negative output terminal of the bidirectional DC-DC power supply and the working ground. The differential amplifier circuit is connected across the sampling resistor to detect the voltage drop across the sampling resistor and output the differential voltage signal. The differential amplifier circuit includes a pair of bipolar transistors, two pull-up resistors, and a filter capacitor. The two emitters of the bipolar junction transistor pair are respectively connected to the two ends of the sampling resistor, and the two collectors of the bipolar junction transistor pair are respectively connected to the power supply VCC and the filter capacitor through the two pull-up resistors, and respectively output the two components of the differential voltage signal.

2. The control circuit for high-speed switching of bidirectional DC-DC power supply charging and discharging according to claim 1, characterized in that, The output current detection and comparison circuit includes a differential comparator; The non-inverting input and inverting input of the differential comparator receive two components of the differential voltage signal, namely input signal VO_ISE_2 and input signal VO_ISE_1, respectively, and compare their voltage magnitudes. When the input signal VO_ISE_2 is greater than the input signal VO_ISE_1, the high / low level signal Vout_CP_D2C output by the differential comparator is high. When the input signal VO_ISE_2 is less than the input signal VO_ISE_1, the high / low level signal Vout_CP_D2C output by the differential comparator is low. The differential comparator outputs the high and low level signals Vout_CP_D2C to the main control unit digital control processor DSC1.

3. The control circuit for high-speed switching of bidirectional DC-DC power supply charging and discharging according to claim 2, characterized in that, The main control unit, digital control processor DSC1, judges the input high and low level signals Vout_CP_D2C. When the high and low level signals Vout_CP_D2C are high, the output current is positive; when the high and low level signals Vout_CP_D2C are low, the output current is negative; when the high and low level signals Vout_CP_D2C change from high to low, the bidirectional DC-DC power supply immediately switches from the discharging state to the charging state; when the high and low level signals Vout_CP_D2C change from low to high, the bidirectional DC-DC power supply immediately switches from the charging state to the discharging state.

4. The control circuit for high-speed switching of bidirectional DC-DC power supply charging and discharging according to claim 3, characterized in that, The output positive and negative current sampling and detection circuit includes an output filter electrolytic capacitor C1, a sampling resistor R3, a bipolar transistor pair VT1, a pull-up resistor R1, a pull-up resistor R2, and a filter capacitor C2. One end of the output filter electrolytic capacitor C1 is connected to the positive output terminal Vout_P of the bidirectional DC-DC power supply, and the other end of the output filter electrolytic capacitor C1 is connected to the working ground GND1. One end of the sampling resistor R3 is connected to the working ground GND1, and the other end of the sampling resistor R3 is connected to pin 3 of the bipolar transistor pair VT1 and the negative output terminal Vout_N of the bidirectional DC-DC power supply, respectively. Pin 4 of the bipolar transistor pair VT1 is connected to the working ground GND1. Pin 1 of the bipolar transistor pair VT1 is connected to one end of the pull-up resistor R1 to form an input signal VO_ISE_1 sent to the output current detection and comparison circuit. Pin 2 of the bipolar transistor pair VT1 is connected to one end of the pull-up resistor R2 to form an input signal VO_ISE_2 sent to the output current detection and comparison circuit. The other ends of the pull-up resistor R1 and the other ends of the pull-up resistor R2 are connected to the power supply VCC. One end of the filter capacitor C2 is connected to the working ground GND1, and the other end of the filter capacitor C2 is connected to the power supply VCC.

5. The control circuit for high-speed switching of bidirectional DC-DC power supply charging and discharging according to claim 4, characterized in that, The output current detection and comparison circuit includes resistors R4 and R5, capacitors C4 and C5, a differential comparator D2, resistors R6 and C6, and capacitor C3. Input signal VO_ISE_2 is connected to one end of resistor R4. The other end of resistor R4 is connected to one end of capacitor C4 and the non-inverting input of differential comparator D2. The other end of capacitor C4 is connected to ground GND1. Input signal VO_ISE_1 is connected to one end of resistor R5. The other end of resistor R5 is connected to one end of capacitor C5 and the inverting input of differential comparator D2. The other end of capacitor C5... The differential comparator D2 is connected to the working ground GND1. Pin 2 of the differential comparator D2 is connected to the working ground GND1. Pin 5 of the differential comparator D2 and one end of the capacitor C6 are respectively connected to the power supply VCC. The other end of the capacitor C6 is connected to the working ground GND1. The output terminal of the differential comparator D2 is connected to one end of the resistor R6. The other end of the resistor R6 is connected to one end of the capacitor C3 to form a high / low level output signal Vout_CP_D2C. The high / low level signal Vout_CP_D2C is output to the main control unit digital control processor DSC1. The other end of the capacitor C3 is connected to the working ground GND1.

6. The control circuit for high-speed switching of bidirectional DC-DC power supply charging and discharging according to claim 5, characterized in that, The overall response time from the change in the output current direction of the bidirectional DC-DC power supply to the receipt of the corresponding high / low level signal Vout_CP_D2C change by the main control unit digital control processor DSC1 is less than or equal to 2 microseconds.

7. A control method for high-speed switching of bidirectional DC-DC power supply charging and discharging, characterized in that, The control method, applied to the control circuit as described in any one of claims 1-6, comprises the following steps: S1. Real-time sampling of the output current of the bidirectional DC-DC power supply; S2. The current signal is converted into the corresponding differential voltage signal through the constructed differential amplifier circuit, namely the input signal VO_ISE_1 and the input signal VO_ISE_2. S3. Compare the input signal VO_ISE_1 and the input signal VO_ISE_2, and generate a high-low level signal Vout_CP_D2C corresponding to the current direction. The high-low level signal Vout_CP_D2C generated when the output current is positive is high-level, and the high-low level signal Vout_CP_D2C generated when the output current is negative is low-level. S4. The main control unit digital control processor DSC1 controls the bidirectional DC-DC power supply to switch from the discharging state to the charging state or from the charging state to the discharging state according to the level change of the high and low level signal Vout_CP_D2C.

8. The control method for high-speed switching of bidirectional DC-DC power supply charging and discharging according to claim 7, characterized in that, In step S1, when a positive current is detected in the discharge state, the output input signal VO_ISE_2 is greater than the input signal VO_ISE_1; when a negative current is detected in the charging state, the output input signal VO_ISE_2 is less than the input signal VO_ISE_1.

9. The control method for high-speed switching of bidirectional DC-DC power supply charging and discharging according to claim 8, characterized in that, The control logic of the main control unit digital control processor DSC1 is as follows: When the high / low level signal Vout_CP_D2C is high, the output current is determined to be positive, and the bidirectional DC-DC power supply is in the discharge state. When the high / low level signal Vout_CP_D2C is low, the output current is determined to be negative, and the bidirectional DC-DC power supply is in a charging state. When the high-level signal Vout_CP_D2C changes from high to low, the bidirectional DC-DC power supply immediately switches from the discharging state to the charging state. When the high / low level signal Vout_CP_D2C changes from low level to high level, the bidirectional DC-DC power supply immediately switches from charging state to discharging state; The total response time for switching from the output current to the high / low level signal Vout_CP_D2C to form the corresponding high / low level is ≤2 microseconds; in step S1, the output current is sampled through sampling resistor R3. The resistance value of the sampling resistor R3 is selected according to the rated current of the detection. When the rated current of the detection is ±200A, the resistance value of the sampling resistor R3 is on the order of 0.1 milliohms.

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