Vehicle-mounted bidirectional charger circuit integrated with vehicle-mounted DC/DC converter
阅读说明：本技术 一种集成车载dc/dc转换器的车载双向充电机电路 (Vehicle-mounted bidirectional charger circuit integrated with vehicle-mounted DC/DC converter ) 是由 肖泽福 范自立 周强 于 2019-10-24 设计创作，主要内容包括：本发明公开了一种集成车载DC/DC转换器的车载双向充电机电路,包括整流模块、DC/DC转换模块、车载DC/DC模块和控制电路,控制电路包括控制模块和电子开关；整流模块和DC/DC转换模块通过直流母线连接,DC/DC转换模块通过电子开关外接动力电池组,车载DC/DC模块的输入端接DC/DC转换模块与电子开关的连接端；整流模块、DC/DC转换模块和车载DC/DC模块的控制端分别接控制模块；在正向电池充电模式下,整流模块作为全桥PWM整流电路进行工作,DC/DC转换模块作为全桥LLC整流电路进行工作；在反向交流电输出模式下,DC/DC转换模块作为全桥LC整流电路进行工作,整流模块作为全桥逆变电路进行工作。本发明的车载双向充电机电路当车载OBC出现故障时,车载DC/DC模块仍然能够正常工作。(The invention discloses a vehicle-mounted bidirectional charger circuit integrated with a vehicle-mounted DC/DC converter, which comprises a rectification module, a DC/DC conversion module, a vehicle-mounted DC/DC module and a control circuit, wherein the control circuit comprises a control module and an electronic switch; the rectification module is connected with the DC/DC conversion module through a direct current bus, the DC/DC conversion module is externally connected with a power battery pack through an electronic switch, and the input end of the vehicle-mounted DC/DC module is connected with the connecting end of the DC/DC conversion module and the electronic switch; the control ends of the rectification module, the DC/DC conversion module and the vehicle-mounted DC/DC module are respectively connected with the control module; in a forward battery charging mode, the rectifying module works as a full-bridge PWM rectifying circuit, and the DC/DC conversion module works as a full-bridge LLC rectifying circuit; in the reverse alternating current output mode, the DC/DC conversion module works as a full-bridge LC rectification circuit, and the rectification module works as a full-bridge inverter circuit. When the vehicle-mounted OBC fails, the vehicle-mounted DC/DC module can still work normally.)
1. A vehicle-mounted bidirectional charger circuit integrated with a vehicle-mounted DC/DC converter comprises a rectification module, a DC/DC conversion module, a vehicle-mounted DC/DC module and a control circuit, wherein the control circuit comprises a control module and an electronic switch; the direct current power supply system is characterized in that the DC/DC conversion module is externally connected with a power battery pack through an electronic switch, the input end of the vehicle-mounted DC/DC module is connected with the connecting end of the DC/DC conversion module and the electronic switch, and the output end of the vehicle-mounted DC/DC module is externally connected with a starting storage battery; the control end of the rectification module, the control end of the DC/DC conversion module and the control end of the vehicle-mounted DC/DC module are respectively connected with the control module; in a forward battery charging mode, the rectifying module works as a full-bridge PWM rectifying circuit, and the DC/DC conversion module works as a full-bridge LLC rectifying circuit; in the reverse alternating current output mode, the DC/DC conversion module works as a full-bridge LC rectification circuit, and the rectification module works as a full-bridge inverter circuit.
2. The circuit of the vehicle-mounted bidirectional charger according to claim 1, wherein the rectifier module comprises an alternating current filter capacitor, a first inductor, a first bus capacitor and 4 switching tubes connected in a bridge manner, the two switching tubes of the first half-bridge adopt MOS tubes, and the two switching tubes of the second half-bridge adopt IGBT tubes; when the rectifying module works as a full-bridge PWM rectifying circuit, the first inductor serves as a boosting inductor; when the rectifier module works as a full-bridge inverter circuit, the first inductor serves as an alternating current filter inductor.
3. The vehicle-mounted bidirectional charger circuit according to claim 2, wherein when the rectifier module operates as a full-bridge PWM rectifier circuit, the control signals of the two switching tubes of the second half-bridge are in a wave-generating waveform of a lagging arm, the switching frequency is 40Hz to 60Hz, the waveforms are complementary, and the switching frequency follows the input alternating current; control signals of the two switching tubes of the first half bridge are leading arm wave-generating waveforms, the switching frequency is fixed high-frequency switching frequency, and stable direct-current bus voltage is obtained by adjusting duty ratios of the two switching tubes of the first half bridge; subtracting the instantaneous direct current bus voltage value from the direct current bus voltage set value, enabling the generated difference value to enter a voltage loop PI regulation, multiplying the value obtained by the voltage loop PI regulation by the input voltage instantaneous value to obtain data, subtracting the input current instantaneous value to obtain a difference value, enabling the difference value to enter a current loop PI regulation, and obtaining a PWM value and the duty ratio of two switching tubes of the first half bridge.
4. The vehicle-mounted bidirectional charger circuit according to claim 2, wherein when the rectifier module operates as a full-bridge inverter circuit, the control signals of the two switching tubes of the second half-bridge are wave-generating waveforms of a lagging arm, the fixed wave-generating frequency is fixed to be 50HZ, and the waveforms are complementary; the control signals of the two switching tubes of the first half bridge are leading arm wave-generating waveforms, the switching frequency is fixed high-frequency switching frequency, the duty ratio of the two switching tubes of the first half bridge is gradually increased from zero to the maximum value and then gradually decreased from the maximum value to zero, and therefore a 50HZ sine wave is obtained; and outputting a difference value generated by subtracting the instantaneous output voltage value from the set voltage value, and then inputting the difference value into a voltage loop PI for regulation to obtain a PWM value for regulating the duty ratio of the two switching tubes of the first half bridge.
5. The vehicle-mounted bidirectional charger circuit according to claim 1, wherein the DC/DC conversion module comprises a first transformer, a primary circuit and a secondary circuit, the primary circuit comprises a second bus capacitor, a resonant inductor and 4 primary switching tubes which are connected in a bridge manner, and the secondary circuit comprises a DC filter capacitor and 4 secondary switching tubes which are connected in a bridge manner; the middle points of the two half bridges of the primary side bridge circuit are connected with a series circuit of a resonant capacitor, a resonant inductor and a primary side winding of the first transformer, and the middle points of the two half bridges of the secondary side bridge circuit are connected with a secondary side winding of the first transformer.
6. The vehicle-mounted bidirectional charger circuit according to claim 5, wherein the duty ratios of the control signals of the primary side switching tube and the secondary side switching tube are both 50%; under a forward battery charging mode, regulating the battery charging voltage output by the DC/DC conversion module by adjusting the switching frequency of a primary side switching tube and a secondary side switching tube; under a reverse alternating current output mode, the direct current bus voltage output by the DC/DC conversion module is adjusted by adjusting the switching frequency of the primary side switching tube and the secondary side switching tube; in both modes, the DC bus voltage is adjusted to follow the voltage of the power battery pack connected to the DC/DC conversion module.
7. The vehicle-mounted bidirectional charger circuit according to claim 6, wherein in the forward battery charging mode, the instantaneous value of the output voltage of the DC/DC conversion module is subtracted from the output voltage value set by the DC/DC conversion module, and the difference value is adjusted by the voltage loop PI to obtain a first difference value; subtracting the current instantaneous value output by the DC/DC conversion module from the output current value set by the DC/DC conversion module, and adjusting the difference value in a current loop PI to obtain a second difference value; comparing the first difference value with the second difference value, and taking the smaller value to adjust the switching frequency of the primary side switching tube and the secondary side switching tube so as to adjust the output voltage of the DC/DC conversion module; in a reverse alternating current output mode, a bus voltage value set by the DC/DC conversion module subtracts a bus voltage instantaneous value output by the DC/DC conversion module, a difference value of the bus voltage value is adjusted in a voltage loop PI, the obtained value is multiplied by an alternating current voltage output by the rectification module, an input current instantaneous value is subtracted, the obtained difference value is adjusted in a current loop PI, and the obtained PWM value is used for adjusting duty ratios of two switching tubes of a first half bridge of a full-bridge PWM rectification circuit of the rectification module.
8. The vehicle-mounted bidirectional charger circuit according to claim 1, wherein the vehicle-mounted DC/DC module comprises a second transformer, a second full-bridge inverter circuit and a full-wave rectifier circuit, the input end of the second full-bridge inverter circuit is connected with the connection end of the DC/DC conversion module and the electronic switch, the output end of the second full-bridge inverter circuit is connected with the primary winding of the second transformer, the input end of the full-wave rectifier circuit is connected with the secondary winding of the second transformer, and the output end of the full-wave rectifier circuit is externally connected with the vehicle-mounted storage battery through; the control end of the switch tube of the second full-bridge inverter and the control end of the switch tube of the full-wave rectification circuit are respectively connected with the control module.
9. The vehicle-mounted bidirectional charger circuit according to claim 8, wherein the control waveforms of the two switching tubes on the half bridge of the second full-bridge inverter circuit are complementary, and the control waveforms of the two switching tubes of the full-wave rectifier circuit are complementary; the duty ratios of 6 switching tubes of the vehicle-mounted DC/DC module are all 50%, and the switching frequencies are the same; the two switching tubes of the second half bridge of the second full-bridge inverter circuit respectively shift phases relative to the two switching tubes of the second half bridge so as to adjust the direct-current voltage output by the vehicle-mounted DC/DC module; the level phases of the two switch tube control signals on the first diagonal of the second full-bridge inverter circuit or the wave-sending waveform of the first switch tube of the full-wave rectification circuit are obtained, and the level phases of the two switch tube control signals on the second diagonal of the second full-bridge inverter circuit or the wave-sending waveform of the second switch tube of the full-wave rectification circuit are obtained.
10. The vehicle-mounted bidirectional charger circuit according to claim 8, characterized in that the instantaneous value of the output voltage of the vehicle-mounted DC/DC module is subtracted from the output voltage value set by the vehicle-mounted DC/DC module, and the difference value is adjusted by the voltage loop PI to obtain a third difference value; subtracting the instantaneous value of the current output by the vehicle-mounted DC/DC module from the output current value set by the vehicle-mounted DC/DC module, and adjusting the difference value in a current loop PI to obtain a fourth difference value; and comparing the fourth difference value with the third difference value, and taking a smaller value to adjust the effective duty cycles of the 4 switching tubes of the second full-bridge inverter circuit and the two switching tubes of the full-wave rectification circuit so as to adjust the output voltage of the vehicle-mounted DC/DC module.
[ technical field ]
The invention relates to a vehicle-mounted bidirectional charger of an electric automobile, in particular to a vehicle-mounted bidirectional charger circuit integrated with a vehicle-mounted DC/DC converter.
[ background art ]
In recent years, with the rapid development of the electric automobile industry, the vehicle-mounted electronic devices tend to be miniaturized, integrated, and highly densified. Particularly, as a core component of electric energy conversion of the electric automobile, a vehicle-mounted charger and a vehicle-mounted DC/DC are urgently required to be miniaturized, integrated and high-density.
The invention with the application number of CN201710559537.5 discloses a novel vehicle-mounted charger main circuit integrated with a DC/DC converter and a control loop thereof, wherein the DC/DC converter and a vehicle-mounted OBC are electrically integrated, and bidirectional energy transfer of the vehicle-mounted OBC can be realized; in addition, a control strategy of synchronous rectification and PWM pulse width modulation wave emission is adopted on the storage battery side, so that the efficiency of the DC/DC functional module is improved to a greater extent; the volume of the whole machine is greatly reduced, the cost is obviously reduced, the power density is obviously improved, and the reliability is further improved.
According to the invention with the application number of CN201710559537.5, the electric energy input by the vehicle-mounted DC/DC module is derived from the second secondary winding of the vehicle-mounted OBC transformer. When the vehicle OBC has a fault, the vehicle DC/DC module cannot work.
[ summary of the invention ]
The invention aims to provide a vehicle-mounted bidirectional charger circuit integrated with a vehicle-mounted DC/DC converter, wherein when a vehicle-mounted OBC fails, a vehicle-mounted DC/DC module can normally work.
In order to solve the technical problems, the technical scheme adopted by the invention is that the vehicle-mounted bidirectional charger circuit integrated with the vehicle-mounted DC/DC converter comprises a rectifying module, a DC/DC conversion module, a vehicle-mounted DC/DC module and a control circuit, wherein the control circuit comprises a control module and an electronic switch; the rectification module is connected with the DC/DC conversion module through a direct current bus, the rectification module is externally connected with alternating current, the DC/DC conversion module is externally connected with a power battery pack through an electronic switch, the input end of the vehicle-mounted DC/DC module is connected with the connecting end of the DC/DC conversion module and the electronic switch, and the output end of the vehicle-mounted DC/DC module is externally connected with a starting storage battery; the control end of the rectification module, the control end of the DC/DC conversion module and the control end of the vehicle-mounted DC/DC module are respectively connected with the control module; in a forward battery charging mode, the rectifying module works as a full-bridge PWM rectifying circuit, and the DC/DC conversion module works as a full-bridge LLC rectifying circuit; in the reverse alternating current output mode, the DC/DC conversion module works as a full-bridge LC rectification circuit, and the rectification module works as a full-bridge inverter circuit.
In the above vehicle-mounted bidirectional charger circuit, the rectifier module includes an ac filter capacitor, a first inductor, a first bus capacitor, and 4 switching tubes connected in a bridge manner, two switching tubes of the first half-bridge adopt MOS tubes, and two switching tubes of the second half-bridge adopt IGBT tubes; when the rectifying module works as a full-bridge PWM rectifying circuit, the first inductor serves as a boosting inductor; when the rectifier module works as a full-bridge inverter circuit, the first inductor serves as an alternating current filter inductor.
When the rectifier module works as a full-bridge PWM rectifier circuit, the control signals of the two switching tubes of the second half-bridge are in a wave-generating waveform of a lagging arm, the switching frequency is 40 Hz-60 Hz, the waveforms are complementary, and the switching frequency follows the input alternating current; control signals of the two switching tubes of the first half bridge are leading arm wave-generating waveforms, the switching frequency is fixed high-frequency switching frequency, and stable direct-current bus voltage is obtained by adjusting duty ratios of the two switching tubes of the first half bridge; subtracting the instantaneous direct current bus voltage value from the direct current bus voltage set value, enabling the generated difference value to enter a voltage loop PI regulation, multiplying the value obtained by the voltage loop PI regulation by the input voltage instantaneous value to obtain data, subtracting the input current instantaneous value to obtain a difference value, enabling the difference value to enter a current loop PI regulation, and obtaining a PWM value and the duty ratio of two switching tubes of the first half bridge.
In the above vehicle-mounted bidirectional charger circuit, when the rectifier module works as a full-bridge inverter circuit, the control signals of the two switching tubes of the second half-bridge are the wave-generating waveforms of the lagging arm, the fixed wave-generating frequency is set to be 50HZ, and the waveforms are complementary; the control signals of the two switching tubes of the first half bridge are leading arm wave-generating waveforms, the switching frequency is fixed high-frequency switching frequency, the duty ratio of the two switching tubes of the first half bridge is gradually increased from zero to the maximum value and then gradually decreased from the maximum value to zero, and therefore a 50HZ sine wave is obtained; and outputting a difference value generated by subtracting the instantaneous output voltage value from the set voltage value, and then inputting the difference value into a voltage loop PI for regulation to obtain a PWM value for regulating the duty ratio of the two switching tubes of the first half bridge.
In the above vehicle-mounted bidirectional charger circuit, the DC/DC conversion module includes the first transformer, the primary circuit and the secondary circuit, the primary circuit includes the second bus capacitor, the resonant inductor and 4 primary switching tubes connected in a bridge manner, and the secondary circuit includes the direct current filter capacitor and 4 secondary switching tubes connected in a bridge manner; the middle points of the two half bridges of the primary side bridge circuit are connected with a series circuit of a resonant capacitor, a resonant inductor and a primary side winding of the first transformer, and the middle points of the two half bridges of the secondary side bridge circuit are connected with a secondary side winding of the first transformer.
In the vehicle-mounted bidirectional charger circuit, the duty ratios of the control signals of the primary side switching tube and the secondary side switching tube are both 50%; under a forward battery charging mode, regulating the battery charging voltage output by the DC/DC conversion module by adjusting the switching frequency of a primary side switching tube and a secondary side switching tube; under a reverse alternating current output mode, the direct current bus voltage output by the DC/DC conversion module is adjusted by adjusting the switching frequency of the primary side switching tube and the secondary side switching tube; in both modes, the DC bus voltage is adjusted to follow the voltage of the power battery pack connected to the DC/DC conversion module.
In the vehicle-mounted bidirectional charger circuit, in the forward battery charging mode, the instantaneous value of the output voltage of the DC/DC conversion module is subtracted from the output voltage value set by the DC/DC conversion module, and the difference value is adjusted by the voltage loop PI to obtain a first difference value; and subtracting the current instantaneous value output by the DC/DC conversion module from the output current value set by the DC/DC conversion module, and adjusting the difference value in a current loop PI to obtain a second difference value. Comparing the first difference value with the second difference value, and taking the smaller value to adjust the switching frequency of the primary side switching tube and the secondary side switching tube so as to adjust the output voltage of the DC/DC conversion module; in a reverse alternating current output mode, a bus voltage value set by the DC/DC conversion module subtracts a bus voltage instantaneous value output by the DC/DC conversion module, a difference value of the bus voltage value is adjusted in a voltage loop PI, the obtained value is multiplied by an alternating current voltage output by the rectification module, an input current instantaneous value is subtracted, the obtained difference value is adjusted in a current loop PI, and the obtained PWM value is used for adjusting duty ratios of two switching tubes of a first half bridge of a full-bridge PWM rectification circuit of the rectification module.
In the vehicle-mounted bidirectional charger circuit, the vehicle-mounted DC/DC module comprises the second transformer, the second full-bridge inverter circuit and the full-wave rectifier circuit, the input end of the second full-bridge inverter circuit is connected to the connection end of the DC/DC conversion module and the electronic switch, the output end of the second full-bridge inverter circuit is connected to the primary winding of the second transformer, the input end of the full-wave rectifier circuit is connected to the secondary winding of the second transformer, and the output end of the full-wave rectifier circuit is connected to the vehicle-mounted storage; the control end of the switch tube of the second full-bridge inverter and the control end of the switch tube of the full-wave rectification circuit are respectively connected with the control module.
In the vehicle-mounted bidirectional charger circuit, the control waveforms of the two switching tubes on the half bridge of the second full-bridge inverter circuit are complementary, and the control waveforms of the two switching tubes of the full-wave rectifier circuit are complementary; the duty ratios of 6 switching tubes of the vehicle-mounted DC/DC module are all 50%, and the switching frequencies are the same; the two switching tubes of the second half bridge of the second full-bridge inverter circuit respectively shift phases relative to the two switching tubes of the second half bridge so as to adjust the direct-current voltage output by the vehicle-mounted DC/DC module; the level phases of the two switch tube control signals on the first diagonal of the second full-bridge inverter circuit or the wave-sending waveform of the first switch tube of the full-wave rectification circuit are obtained, and the level phases of the two switch tube control signals on the second diagonal of the second full-bridge inverter circuit or the wave-sending waveform of the second switch tube of the full-wave rectification circuit are obtained.
In the vehicle-mounted bidirectional charger circuit, the instantaneous value of the output voltage of the vehicle-mounted DC/DC module is subtracted from the output voltage value set by the vehicle-mounted DC/DC module, and the difference value is adjusted by the voltage loop PI to obtain a third difference value; and subtracting the current instantaneous value output by the vehicle-mounted DC/DC module from the output current value set by the vehicle-mounted DC/DC module, and adjusting the difference value in a current loop PI to obtain a fourth difference value. And comparing the fourth difference value with the third difference value, and taking a smaller value to adjust the effective duty cycles of the 4 switching tubes of the second full-bridge inverter circuit and the two switching tubes of the full-wave rectification circuit so as to adjust the output voltage of the vehicle-mounted DC/DC module.
The electric energy input by the vehicle-mounted DC/DC module of the vehicle-mounted bidirectional charger circuit provided by the invention comes from the output of the DC/DC conversion module or the power battery pack, and when the vehicle-mounted OBC has a fault, the vehicle-mounted DC/DC module can still work normally.
[ description of the drawings ]
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
Fig. 1 is a schematic block diagram of a vehicle-mounted bidirectional charger circuit according to an embodiment of the present invention.
Fig. 2 is a topology diagram of a rectifier module according to an embodiment of the present invention.
Fig. 3 is a waveform diagram of a rectifier module in a forward battery charging mode according to an embodiment of the invention.
Fig. 4 is a schematic diagram of the loop control in the forward battery charging mode of the rectifier module according to the embodiment of the present invention.
Fig. 5 is a topology diagram of a DC/DC conversion module according to an embodiment of the present invention.
Fig. 6 is a waveform diagram of a DC/DC conversion module in a forward battery charging mode according to an embodiment of the present invention.
Fig. 7 is a schematic diagram of a loop control in a forward battery charging mode of the DC/DC conversion module according to an embodiment of the present invention.
FIG. 8 is a topology diagram of an onboard DC/DC module in accordance with an embodiment of the present invention.
FIG. 9 is a waveform diagram of an on-board DC/DC module in accordance with an embodiment of the present invention.
FIG. 10 is a schematic diagram of the loop control of the on-board DC/DC module of an embodiment of the present invention.
FIG. 11 is a topology diagram of a control module according to an embodiment of the invention.
Fig. 12 is a waveform diagram of the DC/DC conversion module in the reverse alternating current output mode according to the embodiment of the present invention.
Fig. 13 is a schematic diagram of a loop control in the reverse ac output mode of the DC/DC conversion module according to the embodiment of the present invention.
FIG. 14 is a waveform diagram of the rectifier module according to the embodiment of the present invention in the reverse AC output mode
Fig. 15 is a schematic diagram of the loop control in the reverse ac output mode of the rectifier module according to the embodiment of the present invention.
[ detailed description of the invention ]
The structure of the vehicle-mounted bidirectional charger circuit integrated with the vehicle-mounted DC/DC converter in the embodiment of the invention is shown in FIG. 1, and the vehicle-mounted bidirectional charger circuit comprises a vehicle-mounted bidirectional charger circuit, a vehicle-mounted DC/DC module and a control circuit. The vehicle-mounted bidirectional charger circuit comprises a rectifying module and a DC/DC conversion module, and the control circuit comprises a control module and an electronic switch. The rectification module is connected with the DC/DC conversion module through a direct current bus, and the rectification module is externally connected with alternating current. The DC/DC conversion module is externally connected with a power battery pack through an electronic switch, the input end of the vehicle-mounted DC/DC module is connected with the connecting end of the DC/DC conversion module and the electronic switch, and the output end of the vehicle-mounted DC/DC module is externally connected with a starting storage battery; and the control end of the rectification module, the control end of the DC/DC conversion module and the control end of the vehicle-mounted DC/DC module are respectively connected with the control module. The vehicle-mounted bidirectional charger circuit has two working modes, including a forward battery charging mode in a mode one and a reverse alternating current output mode in a mode two. In a forward battery charging mode, the rectifying module works as a full-bridge PWM rectifying circuit, and the DC/DC conversion module works as a full-bridge LLC rectifying circuit; in the reverse alternating current output mode, the DC/DC conversion module works as a full-bridge LC rectification circuit, and the rectification module works as a full-bridge inverter circuit.
In a forward battery charging mode, the rectifying module works as a full-bridge PWM rectifying circuit, and the DC/DC conversion module works as a full-bridge LLC rectifying circuit; in the reverse alternating current output mode, the DC/DC conversion module works as a full-bridge LC rectification circuit, and the rectification module works as a full-bridge inverter circuit.
As shown in fig. 2, 5 and 8, in the forward battery charging mode, after an input ac current Vin passes through a full-bridge PWM rectifier circuit composed of a filter capacitor C1, a boost inductor L1, MOS transistors Q1, Q2, IGBT transistors Q3, Q4 and a bus electrolytic capacitor C2, and reaches a bus voltage Vbus of 370 Vdc-470 Vdc, a synchronous full-bridge LLC circuit is composed of a bus electrolytic capacitor C3, primary MOS transistors Q5, Q6, Q7, Q8, a resonant capacitor C4, a resonant inductor L1, a main transformer T1-a, secondary MOS transistors Q9, Q10, Q11 and Q12 and a filter capacitor C6, and a charging voltage havcge of 250C-450 Vdc is obtained after rectification, and a
The voltage Vout of 250 Vdc-450 Vdc is simultaneously used as the bus voltage of the vehicle-mounted DC/DC module, the full-bridge phase shift is carried out on 4 MOS tubes Q13, Q14, Q15 and Q16 on the primary side of the vehicle-mounted DC/DC module, full-wave rectification is carried out on MOS tubes Q17 and Q18 on the secondary side, and 14V direct current is obtained to charge the storage battery and the load after a filter inductor L6 and a filter capacitor C9 are carried out.
In a reverse alternating current output mode, after a relay RLY1 is closed by a 250 Vdc-450 Vdc power battery pack voltage VCHAGE to obtain a voltage Vout, part of the output voltage is passed through an input capacitor C6, primary side MOS tubes Q9, Q10, Q11 and Q12, a main transformer T2-A, a secondary side MOS tube Q5, Q6, Q7 and Q8, a resonant capacitor C4, a resonant inductor L1, a main transformer T2-A and a bus electrolytic capacitor C3 to form a full bridge LC circuit, and after a 300 Vdc-470 Vdc bus voltage Vbus is reached, a bus electrolytic capacitor C2, MOS tubes Q1 and Q2, IGBT tubes Q3 and Q4, a filter capacitor C1 and a filter inductor L1 to form a full bridge inverter circuit, so that 220Vac alternating current output can be stably realized in the full range of 250 Vdc-450 Vdc. The other part of the output is used as the vehicle-mounted DC/DC bus voltage, full-bridge phase shifting is carried out on 4 MOS tubes Q13, Q14, Q15 and Q16 on the primary side, full-wave rectification is carried out on MOS tubes Q17 and Q18 on the secondary side, and 14V direct current is obtained to charge the storage battery and the load after a filter inductor L6 and a filter capacitor C9.
As shown in fig. 1, 3, 6, 9, 11 and 12, in the forward and reverse modes, the vehicle-mounted DC/DC converter and the vehicle-mounted bidirectional charger share a control board, and the MCU of the control board transmits PWM1A, PWM1B, PWM2A, PWM2B, PWM3A, PWM3B, PWM4A, PWM4B, PWM5A, PWM5B, PWM6A, PWM6B, PWM7A, PWM7B, PWM8A, PWM8B, PWM9A and PWM9B to drive the MOS tubes Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, Q10 through respective isolation circuits.
As shown in fig. 2, in the forward battery charging mode, after the input of the ac Vin, the ac Vin passes through a full-bridge PWM rectifier circuit composed of a filter capacitor C1, a boost inductor L1, MOS transistors Q1 and Q2, IGBT transistors Q3 and Q4, and a bus electrolytic capacitor C2, and reaches a bus voltage Vbus of 370Vdc to 470 Vdc. Under the reverse alternating current output mode, the bus voltage Vbus forms a full-bridge inverter circuit through an electrolytic capacitor C2, MOS tubes Q1 and Q2, IGBT tubes Q3 and Q4, a filter capacitor C1 and a filter inductor L1, and stable 220Vac alternating current output can be realized within the full range of 250-450 Vdc.
As shown in fig. 3, Vin is an ac input waveform, PWM2A and PWM2B are delayed arm Q3 and Q4 wave-generating waveforms, the switching frequency is 40HZ to 60HZ, the waveforms are complementary and always follow the input ac, whereas PWM1A and PWM1B are advanced arm Q1 and Q2 wave-generating waveforms, the switching frequency is a fixed high-frequency switching frequency, and the stable bus voltage Vbus is obtained by adjusting the duty ratios of PWM1A and PWM1B, and the power factor approaches 1.
As shown in fig. 4, Vref1 IS the voltage value set for the bus voltage, Vbus IS the instantaneous bus voltage value, IS1 IS the instantaneous input current value, and Vin IS the instantaneous input voltage value. And subtracting the Vbus from Vref1 to generate an error value, and then, adding the error value into a voltage loop PI for regulation, multiplying the obtained value by Vin to obtain data, and subtracting the IS1 to generate an error value, and then, adding the error value into a current loop PI for regulation to obtain a PWM value for regulating PWM1A and the duty ratio of PWM1B, thereby obtaining the stable direct-current bus voltage Vbus.
As shown in fig. 5, in the forward mode, the bus voltage Vbus passes through a bus electrolytic capacitor C3, primary side MOS transistors Q5, Q6, Q7, Q8, a resonant capacitor C4, a resonant inductor L1, a main transformer T1-a, secondary side MOS transistors Q9, Q10, Q11, Q12, and a filter capacitor C6 to form a circuit with a synchronous full bridge LLC, and a part of the rectified voltage Vout closes a relay RLY1 to obtain a voltage of 250 Vdc-450 Vdc vchage to charge the power battery pack.
In a reverse alternating current output mode, after a 250 Vdc-450 Vdc power battery pack voltage VCHAGE obtains a voltage Vout through a closed relay RLY1, a part of the voltage Vout passes through an input capacitor C6, primary side MOS tubes Q9, Q10, Q11 and Q12, a main transformer T2-A, secondary side MOS tubes Q5, Q6, Q7 and Q8, a resonant capacitor C4, a resonant inductor L1, a main transformer T2-A and a bus electrolytic capacitor C3 to form a full bridge LC rectifying circuit, and the full bridge LC rectifying circuit reaches a bus voltage Vbus of 300 Vdc-470 Vdc.
As shown in fig. 6, the PWM3A, PWM3B, PWM4A, PWM4B, PWM5A, PWM5B, PWM6A, and PWM6B are eight MOS transistors Q5, Q6, Q7, Q8, Q9, Q10, Q11, and Q12 with wave-generating waveforms, and the waveforms of PWM3A and PWM3B, PWM4A and PWM4B, PWM5A and PWM5B, PWM6A and PWM6B are complementary in pairs, all the duty ratios are fixed duty ratios 50%, and the output voltage VOUT is adjusted by adjusting the switching frequency of the eight MOS transistors.
As shown in fig. 7, Vref1 IS the set output voltage value, Iref2 IS the set output current value, VOUT IS the instantaneous output voltage value, IS2 outputs the current instantaneous value. And subtracting VOUT from Vref2 to generate an error value, and adjusting the error value into a voltage ring PI to obtain a COMP1 value. Iref2 minus IS2 generates an error value into the current loop PI regulation, resulting in a COMP2 value. And comparing the COMP1 value with the COMP2 value, and adjusting the switching frequency of PWM3A, PWM3B, PWM4A, PWM4B, PWM5A, PWM5B, PWM6A and PWM6B to adjust the output voltage VOUT by taking the smaller value.
As shown in fig. 8, the voltage VOUT is used as a bus voltage of the vehicle-mounted DC/DC module, a full-bridge inverter circuit composed of 4 MOS transistors Q13, Q14, Q15, and Q16 on the primary side performs full-bridge phase shift, full-wave rectification is performed on the MOS transistors Q17 and Q18 on the secondary side, and the full-bridge inverter circuit is filtered by a filter inductor L6 and a filter capacitor C9 to obtain 14V direct current to charge the storage battery and the load.
As shown in fig. 9, the PWM7A, PWM7B, PWM8A, PWM8B, PWM9A and PWM9B are six MOS transistors Q13, Q14, Q15, Q16, Q17 and Q18 wave-generating waveforms, the waveforms of the PWM7A and PWM7B, the waveforms of the PWM8A and PWM8B, and the waveforms of the PWM9A and PWM9B are complementary in pairs, the duty ratios of the six MOS transistors are 50%, the switching frequencies are the same, and the phases of the PWM8A and PWM8B are shifted with respect to the phases of the PWM7A and PWM7B, respectively, so as to adjust the output DC voltage DC 14V. The PWM7A and the PWM8B are in the same level or obtain a PWM9B wave-emitting waveform, and the PWM7B and the PWM8A are in the same level or obtain a PWM9A wave-emitting waveform.
As shown in fig. 10, Vref3 IS the output voltage value set by the on-vehicle DC/DC module, Iref3 IS the output current value set by the on-vehicle DC/DC module, DC14V IS the instantaneous voltage output by the on-vehicle DC/DC module, and IS3 IS the instantaneous current output by the on-vehicle DC/DC module. The value of the error generated by subtracting DC14V from Vref3 is fed into voltage loop PI regulation to obtain COMP 3. Iref3 minus IS3 generates an error value into the current loop PI regulation, resulting in a COMP4 value. The COMP3 value is compared with the COMP4 value, and the smaller value PWM8 is selected to adjust the effective duty ratio of PWM7A, PWM7B, PWM8A, PWM8B, PWM9A and PWM 9B.
As shown in fig. 11, the control board is shared in the forward/reverse mode, and the MCUs of the control board transmit PWM1A, PWM1B, PWM2A, PWM2B, PWM3A, PWM3B, PWM4A, PWM4B, PWM5A, PWM5B, PWM6A, PWM6B, PWM7A, PWM7B, PWM8A, PWM8B, PWM9A, and PWM9B to drive 18 MOS transistors, including Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, Q10, Q11, Q12, Q13, Q14, Q15, Q16, Q17, and Q18, through respective isolation circuits.
As shown in fig. 12, the PWM3A, PWM3B, PWM4A, PWM4B, PWM5A, PWM5B, PWM6A and PWM6B are eight MOS transistors Q5, Q6, Q7, Q8, Q9, Q10, Q11 and Q12 with wave-generating waveforms, and the waveforms of PWM3A and PWM3B, PWM4A and PWM4B, PWM5A and PWM5B, PWM6A and PWM6B are complementary in pairs, all the duty ratios are fixed duty ratios of 50%, and the output voltage Vbus is adjusted by adjusting the switching frequency of the eight MOS transistors.
As shown in fig. 13, Vref1 IS the voltage value set for the bus voltage, Vbus IS the instantaneous bus voltage value, IS1 inputs the instantaneous current value, and Vin inputs the instantaneous voltage value. And subtracting the Vbus generated error value from Vref1 to obtain a value, and then adding the value obtained by subtracting the Vbus generated error value to the voltage loop PI for regulation, and then subtracting the IS1 generated error value to obtain a value, and then adding the value obtained by subtracting the IS1 to the current loop PI for regulation, so as to obtain a PWM value for regulating the PWM1A and the duty ratio of the PWM1B, thereby obtaining the stable direct-current bus voltage Vbus.
As shown in fig. 14, Vin is an ac power output waveform, PWM2A and PWM2B are wave-generating waveforms of lagging leg Q3 and Q4, the fixed wave-generating frequency is fixed to 50HZ, and the waveforms are complementary, whereas PWM1A and PWM1B are wave-generating waveforms of leading leg Q1 and Q2, the switching frequency is a fixed high-frequency switching frequency, and the duty ratio is gradually increased from zero to the maximum value and then gradually decreased from the maximum value to zero by adjusting PWM1A and PWM1B, so as to obtain a 50HZ sine wave.
As shown in fig. 15, ref4 IS the voltage value set by the output, Vin IS the instantaneous output voltage value, IS1 IS the instantaneous output current value, and Vin outputs the instantaneous output voltage value. And subtracting the Vin from Vref4 to generate an error value, and then, adjusting the voltage loop PI to obtain a PWM9 value to adjust the duty ratio of PWM1A and PWM1B, thereby realizing stable 220Vac alternating current output within the full range of 250 Vdc-450 Vdc. The IS1 does not participate in the loop here, and only performs output overcurrent protection.
Compared with the prior art, the above embodiment of the invention has the following beneficial effects:
according to the invention with the application number of CN201710559537.5, when the vehicle-mounted OBC transmits energy in the forward direction, the electronic switch needs to be closed, and when the vehicle-mounted OBC transmits energy in the reverse direction, the electronic switch needs to be opened. The electronic switch of the embodiment of the invention is positioned between the DC/DC conversion module and the power battery, and the vehicle-mounted OBC can transfer energy in two directions without switching the electronic switch.
The invention with application number CN201710559537.5 is characterized in that the electric energy input by the vehicle-mounted DC/DC module is sourced from the second secondary winding. The electric energy input by the vehicle-mounted DC/DC module in the above embodiment of the invention comes from the output of the DC/DC conversion module; when the DC/DC conversion module has no output, the electronic switch is closed, and the electric energy input by the vehicle-mounted DC/DC module is sourced from the power battery. According to the invention with the application number of CN201710559537.5, when the vehicle OBC has a fault, the vehicle DC/DC module cannot work, and even if the DC/DC converter has a fault, the vehicle DC/DC module can work normally in the above embodiment of the invention.
In the invention with application number CN201710559537.5, the on-board OBC and the on-board DC/DC module share the transformer T1. In the above embodiment of the invention, the vehicle OBC and the vehicle DC/DC module are respectively provided with the transformers T1 and T3, the transformers are distributed, and the temperature rise is obviously low.
The invention with application number CN201710559537.5 adopts a control strategy of synchronous rectification and PWM pulse width modulation wave generation at the side of the storage battery, and the above embodiment of the invention directly adopts synchronous rectification without PWM pulse width modulation, so that the volume of a control circuit is reduced, and the cost is obviously reduced.