A control circuit for an in-vehicle charger of a totem pole

Abstract

The present invention discloses a control circuit for a totem-pole in-vehicle charger. The control circuit includes a totem-pole power circuit and a PWM control circuit. The PWM control circuit includes a pulse width modulation unit, a control unit, and a delay output unit. The pulse width modulation unit is connected to the output end of the totem-pole power circuit and is used to output a control signal according to the voltage and current output by the totem-pole power circuit; the control unit is connected to the pulse width modulation unit and is used to output a PWM signal according to the control signal; the delay output unit is connected to the control unit and is used to delay the PWM signal and then output it; the control end of the totem-pole power circuit is connected to the delay output unit and is used to control the working state of the totem-pole power circuit according to the delayed PWM signal. In the embodiment of the present invention, the delay output unit delays the PWM signal, which can reduce the dead time of the totem-pole power circuit and improve the overall efficiency and power factor of the totem-pole in-vehicle charger.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of electric vehicles, and in particular to a control circuit for a totem-pole on-vehicle charger. Background Art

[0002] The existing on-vehicle charger controller (On-Board Controller, OBC) includes a totem-pole bridgeless power factor correction circuit (Totem-pole Bridgeless Power Factor Correction) and a power resonant circuit (Logical Link Control, LLC) in a bridge-less interleaved parallel connection. The totem-pole bridgeless power factor correction circuit includes four switching tubes and four diodes. The first bridge arm is composed of two series-connected switching tubes and two series-connected diodes, and the second bridge arm is composed of two series-connected switching tubes and two series-connected diodes. When the totem-pole bridgeless power factor correction circuit works, the above-mentioned devices will all generate power losses, resulting in relatively large power consumption of the totem-pole bridgeless power factor correction circuit.

[0003] In addition, since two switching tubes in the totem-pole bridgeless power factor correction circuit are located on the same bridge arm, a dead time needs to be set to prevent direct short-circuit, and the topology can only work in the current discontinuous and critical conduction modes and cannot work in the current continuous mode. At this time, two switching tubes in the totem-pole are simultaneously in the hard-switching state, resulting in relatively large losses. Summary of the Invention

[0004] The embodiments of the present invention provide a control circuit for a totem-pole on-vehicle charger to further reduce circuit losses and improve the efficiency of the control circuit of the on-vehicle charger.

[0005] The embodiments of the present invention provide a control circuit for a totem-pole on-vehicle charger, including a totem-pole power circuit and a PWM control circuit;

[0006] The PWM control circuit includes a pulse width modulation unit, a control unit, and a delay output unit; the pulse width modulation unit is connected to the output end of the totem-pole power circuit and is used to output a control signal according to the voltage and current output by the totem-pole power circuit. The control unit is connected to the pulse width modulation unit and is used to output a PWM signal according to the control signal. The delay output unit is connected to the control unit and is used to delay and output the PWM signal; the control end of the totem-pole power circuit is connected to the delay output unit and is used to control the working state of the totem-pole power circuit according to the delayed PWM signal.

[0007] Optionally, the delay output unit includes a first delay output sub-unit and a second delay output sub-unit;

[0008] The first delay output subunit and the second delay output subunit are connected to the control unit. The first delay output subunit is configured to delay the PWM signal for a first period of time and then output a first delay signal. The second delay output subunit is configured to delay the PWM signal for a second period of time and then output a second delay signal. The levels of the first delay signal and the second delay signal are opposite to each other.

[0009] Optionally, the first delay output subunit includes a first delay circuit and a first inverting circuit;

[0010] The input end of the first delay circuit is connected to the output end of the control unit. The first delay circuit is configured to delay the PWM signal for the first period of time. The input end of the first inverting circuit is connected to the output end of the first delay circuit. The output end of the first inverting circuit is connected to the first control end of the totem pole power circuit. The first inverting circuit is configured to perform an even-numbered inversion on the PWM signal and then output the first delay signal to the totem pole power circuit.

[0011] Optionally, the delay circuit includes a first capacitor and a first resistor. The first end of the first resistor is connected to the output end of the control unit. The second end of the first resistor is connected to the first pole of the first capacitor and the input end of the first inverting circuit. The second pole of the first capacitor is connected to the ground terminal.

[0012] Optionally, the first delay output subunit further includes a first diode. The positive electrode of the first diode is connected to the output end of the control unit. The negative electrode of the first diode is connected to the input end of the first inverting circuit.

[0013] Optionally, the second delay output subunit includes a second delay circuit and a second inverting circuit;

[0014] The input end of the second delay circuit is connected to the output end of the control unit. The second delay circuit is configured to delay the PWM signal for the second period of time. The input end of the second inverting circuit is connected to the output end of the second delay circuit. The output end of the second inverting circuit is connected to the second control end of the totem pole power circuit. The second inverting circuit is configured to perform an odd-numbered inversion on the PWM signal and then output the second delay signal to the totem pole power circuit.

[0015] Optionally, the delay circuit includes a second capacitor and a second resistor. The first end of the second resistor is connected to the output end of the control unit. The second end of the second resistor is connected to the first pole of the second capacitor and the input end of the second inverting circuit. The second pole of the second capacitor is connected to the ground terminal.

[0016] Optionally, the control unit includes a first switching transistor and a DC power supply;

[0017] The control electrode of the first switching transistor is connected to the pulse width modulation unit, the first electrode of the first switching transistor is connected to the positive electrode of the DC power supply, the second electrode of the first switching transistor is connected to the delay output unit, and the negative electrode of the DC power supply is connected to the ground terminal.

[0018] Optionally, the control unit further includes a second diode and a third diode;

[0019] The first electrodes of the second diode and the third diode are connected to the pulse width modulation unit, and the second electrodes of the second diode and the third diode are connected to the delay output unit.

[0020] Optionally, the on-vehicle charger further includes a filter circuit; the input end of the filter circuit is connected to an AC power supply, and the output end of the filter circuit is connected to the input end of the totem pole power circuit; the filter circuit is used for filtering the power signal provided by the AC power supply.

[0021] In the present invention, the delay output unit in the PWM control circuit delays the PWM signal, so that the delay time of the PWM signal output to the first power switching transistor and the delay time of the PWM signal output to the second power switching transistor can be adjusted as needed, so that the dead time of the first power switching transistor and the second power switching transistor in the totem pole power circuit can be modified through the delay output unit, so that the dead time of the totem pole power circuit can be reduced, and the overall efficiency and power factor of the on-vehicle charger of the totem pole can be improved. Description of the Drawings

[0022] Figure 1 FIG. is a schematic structural diagram of a control circuit of an on-vehicle charger of a totem pole provided by an embodiment of the present invention;

[0023] Figure 2 FIG. is a schematic structural diagram of a PWM control circuit in a control circuit of an on-vehicle charger of a totem pole provided by an embodiment of the present invention;

[0024] Figure 3 FIG. is a schematic diagram of the current flow direction when the totem pole power circuit works in the first stage provided by an embodiment of the present invention;

[0025] Figure 4 FIG. is a schematic diagram of the current flow direction when the totem pole power circuit works in the second stage provided by an embodiment of the present invention;

[0026] Figure 5 FIG. is a schematic diagram of the current flow direction when the totem pole power circuit works in the third stage provided by an embodiment of the present invention;

[0027] Figure 6 This embodiment of the present invention provides a schematic diagram of the current flow when the totem-pole power circuit operates in the fourth stage;

[0028] Figure 7 This embodiment of the present invention provides a schematic diagram of the structure of the PWM control circuit of another totem-pole on-vehicle charger. Detailed implementation manners

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. Additionally, it should be noted that for the sake of description, only parts related to the present invention are shown in the drawings rather than all the structures.

[0030] Before discussing the exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe the steps as sequential processes, many of the steps can be implemented in parallel, concurrently, or simultaneously. In addition, the order of the steps can be rearranged. The process can be terminated when its operation is completed, but it can also have additional steps not included in the drawings. The process can correspond to a method, function, procedure, subroutine, subprogram, etc.

[0031] In addition, terms such as "first", "second", etc. may be used herein to describe various directions, actions, steps, or elements, etc., but these directions, actions, steps, or elements are not limited by these terms. These terms are only used to distinguish the first direction, action, step, or element from another direction, action, step, or element. For example, without departing from the scope of the present application, the first voltage can be referred to as the first voltage, and similarly, the second voltage can be referred to as the first voltage. Both the first voltage and the second voltage are the first voltage, but they are not the same first voltage. The terms "first", "second", etc. should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0032] Figure 1 This is a schematic diagram of the structure of the control circuit of a totem-pole on-vehicle charger provided by an embodiment of the present invention. As Figure 1As shown, the circuit includes a totem-pole power circuit 140 and a PWM control circuit 100; the PWM control circuit 100 includes a pulse-width modulation unit 110, a control unit 120, and a delayed output unit 130; the pulse-width modulation unit 110 is connected to the output terminal of the totem-pole power circuit 140 and is configured to output a control signal according to the voltage and current output by the totem-pole power circuit 140, the control unit 120 is connected to the pulse-width modulation unit 110 and is configured to output a PWM signal according to the control signal, the delayed output unit 130 is connected to the control unit 120 and is configured to output the PWM signal after a delay; the control terminal of the totem-pole power circuit 140 is connected to the delayed output unit 130 and is configured to control the operating state of the totem-pole power circuit 140 according to the delayed PWM signal.

[0033] Specifically, the totem-pole power circuit 140 may include two bridge arms, and each bridge arm includes two power switching transistors and two diodes. Exemplarily, as Figure 1As shown, one leg of the totem-pole power circuit 140 includes a first power switch S1, a second power switch S2, a first freewheeling diode SD1, and a second freewheeling diode SD2, and the other leg includes a third power switch S3, a fourth power switch S4, a third freewheeling diode SD3, a fourth freewheeling diode SD4, a first output resistor RO1, and a second output resistor RO2. The control electrodes of the two power switches in each leg serve as the control terminals of the totem-pole power circuit 140 for controlling the operating state of the totem-pole power circuit 140. Exemplarily, the control electrode of the first power switch S1 serves as the first control terminal of the totem-pole power circuit 140, and the control electrode of the second power switch S2 serves as the second control terminal of the totem-pole power circuit 140. Additionally, the first pole of the first power switch S1 and the cathode of the first freewheeling diode SD1, and the first pole of the third power switch S3 and the cathode of the third freewheeling diode SD3 are connected, and the second pole of the second power switch S2 and the anode of the second freewheeling diode SD2, and the second pole of the fourth power switch S4 and the anode of the fourth freewheeling diode SD4 are connected, and are respectively used as the two voltage output terminals VO of the totem-pole power circuit 140. The second pole of the first power switch S1 and the anode of the first freewheeling diode SD1, and the first pole of the second power switch S2 and the cathode of the second freewheeling diode SD2 are connected to the positive pole of the power supply AC. The second pole of the third power switch S3 and the anode of the third freewheeling diode SD3 are connected to the first pole of the first output resistor RO1. The first pole of the fourth power switch S4 and the cathode of the fourth freewheeling diode SD4 are connected to the second pole of the second output resistor RO2. The second pole of the first output resistor RO1 and the first pole of the second output resistor RO2 are connected to the negative pole of the power supply AC through the relay contact J1 and serve as the current output terminal IO of the totem-pole power circuit 140. Among them, the relay contact J1 is used to control whether the power supply AC supplies power to the totem-pole power circuit 140. The totem-pole power circuit 140 further includes an output capacitor CO and a load resistor RD. The first pole of the output capacitor CO and the first pole of the load resistor RD are connected to the first pole of the third power switch S3, and the second pole of the output capacitor CO and the second pole of the load resistor RD are connected to the second pole of the fourth power switch S4 to output the voltage signal output by the totem-pole power circuit 140.

[0034] The pulse width modulation unit 110 may be a pulse width modulator 110, which may include a voltage input terminal VIN and a current input terminal IIN. The voltage input terminal VIN is connected to the voltage output VO terminal of the totem pole power circuit 140 for obtaining the voltage signal output by the totem pole power circuit 140. The current input terminal IIN is connected to the current output terminal IO of the totem pole power circuit 140 for obtaining the current signal output by the totem pole power circuit 140. The pulse width modulation unit 110 may calculate the power output by the totem pole power according to the input voltage signal and current signal, and then compare it with the reference power preset in the pulse width modulation unit 110, and output a control signal. Among them, the control signal may include a first level and a second level. The control unit 120 may output a PWM signal according to the control signal, and the duty cycle of the PWM signal is related to the first level and the second level of the control signal. The PWM signal is delayed by the delay output unit 130 and then output to the totem pole power circuit 140 to control the working state of the totem pole power circuit 140, thereby adjusting the output power of the totem pole power circuit 140. Exemplarily, the PWM signal may be used to control the conduction time of the first power switch tube S1 and the second power switch tube S2. When the power output by the totem pole power circuit 140 is relatively small, the pulse width modulation unit 110 may adjust the duration of the first level or the second level output by the control signal, so that the duty cycle of the PWM signal output by the control unit 120 increases. Thus, after the PWM signal is delayed and output, the conduction time of the first power switch tube S1 and the second power switch tube S2 can be controlled to increase, so that the power output by the totem pole power circuit 140 can be increased, and the output adjustment of the totem pole power circuit 140 can be realized.

[0035] In the above process, the delay output unit 130 in the PWM control circuit 100 can delay the PWM signal, so that the delay time of the PWM signal output to the first power switch tube S1 and the delay time of the PWM signal output to the second power switch tube S2 can be adjusted as needed. Thus, the dead time of the first power switch tube S1 and the second power switch tube S2 in the totem pole power circuit can be modified by the delay output unit 130, so that the dead time of the totem pole power circuit can be reduced, and the overall efficiency and power factor of the on-vehicle charger of the totem pole can be improved.

[0036] Continue to refer to Figure 1, the delay output unit 130 includes a first delay output subunit 131 and a second delay output subunit 132. The first delay output subunit 131 and the second delay output subunit 132 are connected to the control unit 120. The first delay output subunit 131 is configured to delay the PWM signal for a first time and then output a first delayed signal PWM_H, and the second delay output subunit 132 is configured to delay the PWM signal for a second time and then output a second delayed signal PWM_L. The levels of the first delayed signal PWM_H and the second delayed signal PWM_L are opposite.

[0037] Specifically, both the first delay output subunit 131 and the second delay output subunit 132 are connected to the control unit 120. When the control unit 120 outputs a PWM signal, the first delay output subunit 131 and the second delay output subunit 132 can delay and output the PWM signal simultaneously. Since the first delay output subunit 131 delays and outputs the PWM signal for a first time, and the second delay output subunit 132 delays and outputs the PWM signal for a second time, the times when the PWM signal is output to the first control end and the second control end of the totem-pole power circuit 140 are different. The first control end and the second control end can be the control poles of two power switching transistors in the same bridge arm of the totem-pole power circuit 140. Thus, the conduction moments of the two power switching transistors in the same bridge arm of the totem-pole power circuit 140 can be controlled, and further, the dead time of the two power switching transistors in the same bridge arm can be reduced, improving the overall efficiency and power factor of the totem-pole on-vehicle charger. Exemplarily, when the control pole of the first power switching transistor S1 in the totem-pole power circuit 140 is used as the first control end of the totem-pole power circuit 140, and the control pole of the second power switching transistor S2 is used as the second control end of the totem-pole power circuit 140, at this time, the conduction moment of the first power switching transistor S1 can be adjusted by the first delay output subunit 131, and the conduction moment of the second power switching transistor S2 can be adjusted by the second delay output subunit 132. Thus, the dead time of the bridge arm where the first power switching transistor S1 and the second power switching transistor S2 are located can be reduced according to the different conduction moments of the first power switching transistor S1 and the second power switching transistor S2, improving the overall efficiency and power factor of the totem-pole on-vehicle charger. Wherein, the durations of the first time delay and the second time delay of the PWM signal may not be equal. In addition, the types of the power switching transistors in the same bridge arm of the totem-pole power circuit 140 are the same. By setting the levels of the first delayed signal PWM_H and the second delayed signal PWM_L to be opposite, one of the two power switching transistors on the same bridge arm can be controlled to conduct, and the other to cut off.

[0038] Figure 2 FIG. is a schematic structural diagram of a PWM control circuit in a control circuit of a totem-pole on-vehicle charger provided by an embodiment of the present invention, as Figure 2As shown, the first delay output sub-unit 131 includes a first delay circuit 1311 and a first inverter circuit 1312.

[0039] The input end of the first delay circuit 1311 is connected to the output end of the control unit 120. The first delay circuit 1311 is used to delay the PWM signal for a first period of time. The input end of the first inverter circuit 1312 is connected to the output end of the first delay circuit 1311. The output end of the first inverter circuit 1312 is connected to the first control end of the totem pole power circuit 140. The first inverter circuit 1312 is used to perform an even number of inversions on the PWM signal and then output a first delay signal PWM_H to the totem pole power circuit 140.

[0040] Specifically, the first delay circuit 1311 can delay the PWM signal for a first period of time and then output it to the first inverter circuit 1312. After the first inverter circuit 1312 performs an even number of inversions on the delayed PWM signal, the level of the delayed PWM signal remains unchanged, and then it is transmitted to the first control end of the totem pole power circuit 140, so that the control signal at the input end of the first control end of the totem pole power circuit 140 is the same as the level of the PWM signal. Exemplarily, the first inverter circuit 1312 can include an even number of inverters for inverting the delayed PWM signal.

[0041] In other embodiments, with continued reference to Figure 2 , the first delay circuit 1311 includes a first capacitor C1 and a first resistor R1. The first end of the first resistor R1 is connected to the output end of the control unit 120. The second end of the first resistor R1 is connected to the first pole of the first capacitor C1 and the input end of the first inverter circuit 1312. The second pole of the first capacitor C1 is connected to the ground terminal.

[0042] Specifically, the first resistor R1 and the first capacitor C1 are connected in series to form the first delay circuit 1311. The delay time of the first delay circuit 1311 can be determined by adjusting the resistance value of the first resistor R1 and the capacitance value of the first capacitor C1. The second end of the first resistor R1 serves as the output end of the first delay circuit 1311 and is connected to the input end of the first inverter circuit 1312. The PWM signal is input to the first inverter circuit 1312 after passing through the first resistor R1, and the first inverter circuit 1312 performs an even number of inversions according to the delayed PWM signal and outputs.

[0043] With continued reference to Figure 2 , the first delay output sub-unit 131 further includes a first diode D1 for preventing the PWM signal generated at the control end from propagating backward. The positive pole of the first diode D1 is connected to the output end of the control unit 120, and the negative pole of the first diode D1 is connected to the input end of the first inverter circuit 1312.

[0044] Specifically, the first diode D1 is a unidirectional conduction device. By connecting the anode of the first diode D1 to the control unit 120 and the cathode of the first diode D1 to the input terminal of the first inverter circuit 1312, external signals can be prevented from being fed back through the first inverter circuit 1312.

[0045] Continuing to refer to Figure 2 , the second delay output sub-unit 132 includes a second delay circuit 1321 and a second inverter circuit 1322.

[0046] The input terminal of the second delay circuit 1321 is connected to the output terminal of the control unit 120. The second delay circuit 1321 is used to delay the PWM signal for a second period of time. The input terminal of the second inverter circuit 1322 is connected to the output terminal of the second delay circuit 1321. The output terminal of the second inverter circuit 1322 is connected to the second control terminal of the totem pole power circuit 140. The second inverter circuit 1322 is used to invert the PWM signal an odd number of times and then output a second delayed signal PWM_L to the totem pole power circuit 140.

[0047] Specifically, the second delay circuit 1321 can delay the PWM signal for a second period of time and then output it to the second inverter circuit 1322. After the second inverter circuit 1322 inverts the delayed PWM signal an odd number of times, the level of the delayed PWM signal is changed between high and low, and then it is transmitted to the second control terminal of the totem pole power circuit 140, so that the control signal at the input terminal of the second control terminal of the totem pole power circuit 140 is opposite to the level of the PWM signal. Exemplarily, the second inverter circuit 1322 can include an odd number of inverters for inverting the delayed PWM signal.

[0048] In other embodiments, continuing to refer to Figure 2 , the second delay circuit includes a second capacitor C2 and a second resistor R2. The first end of the second resistor R2 is connected to the output terminal of the control unit 120. The second end of the second resistor R2 is connected to the first pole of the second capacitor C2 and the input terminal of the second inverter circuit 1322. The second pole of the second capacitor C2 is connected to the ground terminal.

[0049] Specifically, the second resistor R2 and the second capacitor C2 are connected in series to form the second delay circuit 1321. The delay time of the second delay circuit 1321 can be determined by adjusting the resistance value of the second resistor R2 and the capacitance value of the second capacitor C2. The second end of the second resistor R2 serves as the output terminal of the second delay circuit 1322 and is connected to the input terminal of the second inverter circuit 1322. The PWM signal passes through the second resistor R2 and then is input to the second inverter circuit 1322, and the second inverter circuit 1322 outputs an odd-numbered inversion according to the delayed PWM signal.

[0050] Continuing to refer to Figure 2, wherein, the control unit 120 includes a first switching transistor Q1 and a DC power supply DC.

[0051] The control electrode of the first switching transistor Q1 is connected to the pulse width modulation unit 110, the first electrode of the first switching transistor Q1 is connected to the positive pole of the DC power supply, the second electrode of the first switching transistor Q1 is connected to the delay output unit 130, and the negative pole of the DC power supply is connected to the ground terminal.

[0052] Specifically, the first switching transistor Q1 can be an N-type switching transistor. When the control signal is at a high level, it can control the first switching transistor Q1 to conduct. At this time, the DC signal of the DC power supply DC can be transmitted to the delay output unit 130 through the first switching transistor Q1. When the control signal is at a low level, it can control the first switching transistor Q1 to cut off. At this time, the DC signal provided by the DC power supply DC cannot be transmitted to the delay output unit 130 through the first switching transistor Q1, and the control signal is transmitted to the delay output unit 130 through the second diode and the third diode. Thus, the duty ratio of the PWM signal obtained by the output delay unit 130 can be adjusted by controlling the conduction time of the first switching transistor Q1 with the control signal. In the above process, the present invention adjusts its own state through the first switching transistor Q1 to quickly respond to the control signal provided by the pulse width modulation unit 110 to generate a PWM signal. Compared with the process of generating a PWM signal through a software algorithm, it can improve the rate of the voltage signal and current signal output by the response totem pole power circuit 140, thereby reducing the delay of generating the PWM signal itself, which is beneficial to further reducing the dead time of the totem pole power circuit 140 and improving the overall efficiency and power factor of the on-vehicle charger.

[0053] Continue to refer to Figure 2 , the control unit 120 further includes a second diode D2 and a third diode D3.

[0054] The first electrode of the second diode D2 and the first electrode of the third diode D3 are connected to the pulse width modulation unit 110, and the second electrode of the second diode D2 and the second electrode of the third diode D3 are connected to the delay output unit 130.

[0055] Specifically, the second diode D2 and the third diode D3 are unidirectional conduction devices. By setting the first electrode of the second diode D2 and the first electrode of the third diode D3 to be connected to the output terminal of the pulse width modulation unit 110, when the control signal provided by the pulse width modulation unit 110 controls the control unit 120 and cannot provide the DC signal of the DC power supply DC, the control signal is directly transmitted to the delay output unit 130 through the second diode D2 and the third diode D3, providing a signal with a level opposite to that of the DC signal for the delay output unit 130, so that the control unit 120 can provide a PWM signal for the delay output unit 130. Exemplarily, such as Figure 2As shown, the first poles of the second diode D2 and the third diode D3 can be set as the negative poles, and the second poles of the second diode D2 and the third diode D3 can be set as the positive poles. When the first switching transistor is an N-type switching transistor and the control signal output by the pulse width modulation unit 110 is at a high level, the second diode D2 and the third diode D3 are cut off, and the first switching transistor is turned on to provide a high level for the delay output unit. When the control signal output by the pulse width modulation unit 110 is at a low level, the first switching transistor is cut off, and then the control signal can provide a low level for the first delay output sub-unit 131 and the second delay circuit 1321 through the second diode D2 and the third diode D3. Thus, the duty cycle of the PWM signal can be adjusted by controlling the conduction time of the first switching transistor. Then, the PWM signal is output to the totem pole power circuit 140 through the delay output unit 130 to control the totem pole power circuit 140 to output power according to the PWM signal.

[0056] Figure 3 FIG. is a schematic diagram of the current flow direction when the totem pole power circuit provided by the embodiment of the present invention operates in the first stage. As Figure 3 shown, when the alternating current provided by the power supply AC is in the positive half cycle, the signal provided by the first control terminal controls the first power switch tube S1 to be cut off, the signal provided by the second control terminal controls the second power switch tube S2 to be turned on, and at the same time controls the fourth power switch tube S4 to be turned on. At this time, the signal output from the positive pole of the power supply AC is transmitted to the first pole of the second power switch tube S2 through the inductor L1, then transmitted to the fourth power switch tube S4 through the second power switch tube S2, and transmitted to the negative pole of the power supply AC through the fourth power switch tube S4 and the fourth freewheeling diode SD4, forming a loop. Figure 4 FIG. is a schematic diagram of the current flow direction when the totem pole power circuit provided by the embodiment of the present invention operates in the second stage. As Figure 4 shown, when the alternating current provided by the power supply AC is in the positive half cycle, the signal provided by the first control terminal controls the first power switch tube S1 to be cut off, the signal provided by the second control terminal controls the second power switch tube S2 to be cut off, and at the same time controls the fourth power switch tube S4 to be turned on. At this time, the signal output from the positive pole of the power supply AC is transmitted to the positive pole of the first freewheeling diode SD1 through the inductor L1, and output through the first freewheeling diode SD1, then transmitted to the fourth power switch tube S4 through the load, and transmitted to the negative pole of the power supply AC through the fourth power switch tube S4 and the fourth freewheeling diode SD4, forming a loop. Since in the second stage, both the first power switch tube S1 and the second power switch tube S2 are cut off, at this time, the signal provided by the power supply AC can form a loop through the first freewheeling diode SD1, thereby reducing the power loss caused by the cut-off voltage drop of the first freewheeling diode SD1. Figure 5 FIG. is a schematic diagram of the current flow direction when the totem pole power circuit provided by the embodiment of the present invention operates in the third stage. As Figure 5As shown, when the alternating current provided by the power supply AC is in the negative half-cycle, the signal provided by the first control terminal controls the first power switch tube S1 to conduct, the signal provided by the second control terminal controls the second power switch tube S2 to cut off, and at the same time controls the third power switch tube S3 to conduct. At this time, the signal output from the positive pole of the power supply AC is transmitted to the first pole of the third power switch tube S3, then transmitted to the first power switch tube S1 through the third power switch tube S3, and transmitted to the negative pole of the power supply AC through the inductor L1, forming a loop. Figure 6 Schematic diagram of the current flow when the totem-pole power circuit provided by the embodiment of the present invention operates in the fourth stage. As Figure 6 shown, when the alternating current provided by the power supply AC is in the negative half-cycle, the signal provided by the first control terminal controls the first power switch tube S1 to cut off, the signal provided by the second control terminal controls the second power switch tube S2 to cut off, and at the same time controls the third power switch tube S3 to conduct. At this time, the signal output from the positive pole of the power supply AC is transmitted to the third power switch tube S3, and transmitted to the negative pole of the power supply AC through the load and the second freewheeling diode SD2, forming a loop. Since in the fourth stage, both the first power switch tube S1 and the second power switch tube S2 are cut off, at this time, the signal provided by the power supply AC can form a loop through the second freewheeling diode SD2, thereby reducing the power loss caused by the cut-off voltage drop of the second freewheeling diode SD2.

[0057] When the totem-pole on-vehicle charger control circuit in the embodiment of the present invention is working, it can reduce the power loss caused by the cut-off voltage drops of the first freewheeling diode SD1 and the second freewheeling diode SD2. Therefore, it can further reduce the power loss and further improve the overall efficiency of the on-vehicle charger.

[0058] Figure 7 Schematic diagram of the structure of the PWM control circuit of another totem-pole on-vehicle charger provided by the embodiment of the present invention. Optionally, as Figure 7 shown, the control circuit of the totem-pole on-vehicle charger further includes a filter circuit 150. The input end of the filter circuit is connected to the AC power supply, and the output end of the filter circuit is connected to the input end of the totem-pole power circuit; the filter circuit is used to filter the power supply signal provided by the AC power supply.

[0059] Exemplarily, the filtering circuit 150 can be divided into a three-stage filtering circuit. The first-stage filtering circuit includes a third capacitor C3 and a first transformer T1. Both ends of the third capacitor C3 are also connected to both ends of the high-voltage end of the first transformer T1. Both ends of the low-voltage end of the first transformer T1 are connected to both ends of a fourth capacitor C4, for outputting a first-stage filtered voltage. The second-stage filtering circuit includes the fourth capacitor C4 and a second transformer T2. Both ends of the fourth capacitor C4 are connected to both ends of the high-voltage end of the second transformer T2. Both ends of the low-voltage end of the second transformer T2 are connected to both ends of a fifth capacitor C5, for outputting a second-stage filtered voltage. The third-stage filtering circuit includes the fifth capacitor C5 and an inductor L1. The first end of the fifth capacitor C5 is connected to the inductor L1, and the second end of the fifth capacitor C5 is connected to the first end of a relay J1.

[0060] The third capacitor C3, the first transformer T1, the fourth capacitor C4, the second transformer T2, the fifth capacitor C5 and the inductor L1 constitute a three-stage LC filtering circuit. The filtering circuit is used to filter the power signal provided by the AC power supply and output a filtered voltage. When the control circuit of the totem-pole in-vehicle charger works, filtering the 220V alternating current can obtain a better electrical signal and stably output the voltage.

[0061] Note that the above is only a preferred embodiment of the present invention and the technical principles applied. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein. Various obvious changes, re-adjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, more other equivalent embodiments can be included, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A control circuit for an in-vehicle charger of a totem pole, characterized in that, It includes a totem pole power circuit and a PWM control circuit; The PWM control circuit includes a pulse width modulation unit, a control unit, and a delay output unit; the pulse width modulation unit is connected to the output end of the totem pole power circuit and is used to output a control signal according to the voltage and current output by the totem pole power circuit. The control unit is connected to the pulse width modulation unit and is used to output a PWM signal according to the control signal. The delay output unit is connected to the control unit and is used to output the PWM signal after a delay; the control end of the totem pole power circuit is connected to the delay output unit and is used to control the working state of the totem pole power circuit according to the delayed PWM signal; The delay output unit includes a first delay output sub-unit and a second delay output sub-unit; The first delay output sub-unit and the second delay output sub-unit are connected to the control unit. The first delay output sub-unit is used to output a first delay signal after delaying the PWM signal for a first time. The second delay output sub-unit is used to output a second delay signal after delaying the PWM signal for a second time. The levels of the first delay signal and the second delay signal are opposite; The control unit includes a first switching tube and a DC power supply; The control electrode of the first switching tube is connected to the pulse width modulation unit. The first pole of the first switching tube is connected to the positive pole of the DC power supply. The second pole of the first switching tube is connected to the delay output unit. The negative pole of the DC power supply is connected to the ground terminal.

2. The control circuit of the in-vehicle charger of the totem pole according to claim 1, characterized in that, The first delay output sub-unit includes a first delay circuit and a first inverting circuit; The input end of the first delay circuit is connected to the output end of the control unit, and the first delay circuit is used to delay the PWM signal for the first time; The input end of the first inverting circuit is connected to the output end of the first delay circuit, and the output end of the first inverting circuit is connected to the first control end of the totem pole power circuit. The first inverting circuit is used to output the first delay signal to the totem pole power circuit after performing an even-numbered inversion on the PWM signal.

3. The control circuit of the in-vehicle charger of the totem pole according to claim 2, characterized in that, The first delay circuit includes a first capacitor and a first resistor. The first end of the first resistor is connected to the output end of the control unit. The second end of the first resistor is connected to the first pole of the first capacitor and the input end of the first inverting circuit. The second pole of the first capacitor is connected to the ground terminal.

4. The control circuit of the in-vehicle charger of the totem pole according to claim 2, characterized in that, The first delay output sub-unit further includes a first diode; the positive pole of the first diode is connected to the output end of the control unit, and the negative pole of the first diode is connected to the input end of the first inverting circuit.

5. The control circuit of the on-vehicle charger of the totem pole according to any one of claims 1-4, characterized in that The second delay output sub-unit includes a second delay circuit and a second inverting circuit; The input end of the second delay circuit is connected to the output end of the control unit. The second delay circuit is used to delay the PWM signal for the second time. The input end of the second inverting circuit is connected to the output end of the second delay circuit, and the output end of the second inverting circuit is connected to the second control end of the totem pole power circuit. The second inverting circuit is used to perform odd-order inversion on the PWM signal and then output the second delay signal to the totem pole power circuit.

6. The control circuit of the in-vehicle charger of the totem pole according to claim 5, characterized in that, The second delay circuit includes a second capacitor and a second resistor. The first end of the second resistor is connected to the output end of the control unit, the second end of the second resistor is connected to the first pole of the second capacitor and the input end of the second inverting circuit, and the second pole of the second capacitor is connected to the ground terminal.

7. The control circuit of the on-vehicle charger of the totem pole according to claim 1, characterized in that, The control unit further includes a second diode and a third diode. The first poles of the second diode and the third diode are connected to the pulse width modulation unit, and the second poles of the second diode and the third diode are connected to the delay output unit.

8. The control circuit of the on-vehicle charger of the totem pole according to claim 1, characterized in that, A filter circuit is further included. The input end of the filter circuit is connected to the AC power supply, and the output end of the filter circuit is connected to the input end of the totem pole power circuit. The filter circuit is used to filter the power signal provided by the AC power supply.

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