Single-phase three-phase compatible charger control circuit and control method for reducing electrolytic capacitors

Abstract

The present invention discloses a single-phase three-phase compatible charger control circuit and a control method for reducing electrolytic capacitors, wherein the control circuit comprises a first, a second and a third AC / DC conversion module respectively connected to the three phase lines of the power grid, and the output ends of the first, the second and the third AC / DC conversion modules are connected in parallel and then connected to a battery; the bus capacitor of the first AC / DC conversion module adopts a large-capacitance bus capacitor, and the bus capacitor of the second and the third AC / DC conversion modules adopts a small-capacitance bus capacitor C Fbus ; In the single-phase working mode, only the first AC-DC conversion module is put into operation; in the three-phase working mode, the first, second and third AC-DC conversion modules are all put into operation; the present invention can reduce the electrolytic capacitor, improve the power density of the charger, increase the life of the charger, reduce the size of the charger, and at the same time suppress the output charging current ripple to maintain a stable charging performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric vehicle charging, and in particular relates to a single-phase or three-phase compatible charger control circuit and a control method thereof for reducing electrolytic capacitors. Background Art

[0002] With the need to save energy and reduce emissions, as well as control air pollution, new energy vehicles are gradually being commercialized in the market, and electric vehicles are the main force of new energy vehicles. With the increase in driving range, the capacity of electric vehicle power batteries is also growing. In order to reduce the waiting time for charging, the demand for high-power on-board chargers is becoming more and more intense. High-power chargers with three-phase input will become the main force in the future market.

[0003] At present, vehicles require longer and longer life of charger power supply, and the working environment is getting worse and worse (high temperature and large amplitude). The use of a large number of electrolytic capacitors in traditional power supplies restricts the life of chargers. At the same time, with the rapid update of semiconductor technology, high-frequency and high-density chargers have become the focus of various OEMs and parts. For example, a typical 6.6kW charger requires about 1000uF electrolytic capacitors, and the volume of electrolytic capacitors accounts for about 10% of the volume of the entire charger board.

[0004] Figure 1 It is an existing conventional single-phase and three-phase compatible charger. The charger consists of three independent AC / DC conversion modules. The input is connected to L1~L3 and N line respectively, and the output charges the battery through parallel combination. Figure 2 yes Figure 1 The block diagram of the AC / DC conversion module in the figure. The module consists of two stages, and the middle bus capacitor is composed of an electrolytic capacitor C Ebus and film (or ceramic capacitor) C Fbus It is composed of a capacitor and is used to store energy, so that AC energy is input and constant DC energy is output. Figure 3 The input voltage and current, input power and output power diagram for a conventional 220V 32A AC input. Due to the difference between input power and output power, conventional bidirectional converters need to use bus capacitors to periodically store and release energy. Existing single-phase and three-phase compatible on-board chargers have the disadvantages of low efficiency, use of more electrolytic capacitors, and large size.

[0005] In order to improve power density and extend the life of the charger, the industry hopes to reduce or remove the PFC bus electrolytic capacitor inside the charger, but this will result in excessive charging ripple current during single-phase charging. Therefore, the industry urgently needs to develop a single-phase and three-phase compatible charger control circuit with low charging ripple current, less electrolytic capacitor usage, and small size and high power density. Summary of the invention

[0006] The present invention aims to solve the above problems in the prior art and proposes a single-phase and three-phase compatible charger control circuit and a control method thereof which can reduce electrolytic capacitors.

[0007] The technical solution adopted by the present invention is to design a single-phase three-phase compatible charger control circuit with reduced electrolytic capacitors, which includes a first, a second and a third AC / DC conversion module respectively connected to the three phase lines of the power grid, and the output ends of the first, the second and the third AC / DC conversion modules are connected in parallel and then connected to the battery; the bus capacitor of the first AC / DC conversion module adopts a large-capacitance bus capacitor, and the bus capacitor of the second and the third AC / DC conversion modules adopts a small-capacitance bus capacitor C Fbus ; In the single-phase working mode, only the first AC-DC conversion module is put into operation; in the three-phase working mode, the first, second and third AC-DC conversion modules are all put into operation.

[0008] The first, second and third AC / DC conversion modules all include a PFC module and a DCDC module, wherein the PFC module and the DCDC module are connected via a positive bus and a negative bus; a small-capacitance bus capacitor C is connected in parallel between the positive and negative bus of the first AC / DC conversion module. Fbus And large value capacitor C Ebus A small bus capacitor C is provided between the positive and negative busbars of the second and third AC / DC conversion modules. Fbus .

[0009] The large capacitance capacitor C Ebus Electrolytic capacitors are used, and the small-capacitance bus capacitor C Fbus Use film capacitors or ceramic capacitors.

[0010] The large capacitance capacitor C Ebus A control switch S is connected in series and is controlled by a controller; in a single-phase working mode, the control switch S is closed; in a three-phase working mode, the control switch S is opened.

[0011] In the three-phase working mode, the first, second and third AC / DC conversion modules are respectively connected to their respective controllers, and the controller includes a PFC module current sampler, a PFC module voltage sampler, a DCDC module output end current sampler, and a DCDC module output end voltage sampler; the DCDC module output end current sampler and the DCDC module output end voltage sampler are connected to two input ends of the first multiplier, the output end of the first multiplier is connected to the subtrahend input end of the first subtractor, and the minuend input end of the first subtractor is connected to the charging power setting value, the output end of the first subtractor is connected to the first PID regulator, the output end of the first PID regulator is connected to one input end of the second multiplier, and the other input end of the second multiplier is connected to the PFC module voltage sampler, the output end of the second multiplier is connected to the minuend input end of the second subtractor, the minuend input end of the second subtractor is connected to the PFC module current sampler, the output end of the second subtractor is connected to the input end of the second PID regulator, and the output end of the second PID regulator is connected to the first PWM controller, and the first PWM controller controls the PFC module. The controller includes a positive and negative bus voltage sampler, the output end of the positive and negative bus voltage sampler is connected to the subtrahend end of the third subtractor, the minuend end of the third subtractor is connected to the bus voltage setting value Vpfc_ref, the output end of the third subtractor is connected to the input end of the third PID regulator, the output end of the third PID regulator is connected to the second PWM controller, and the second PWM controller controls the DCDC module.

[0012] In a design scheme, in a single-phase working mode, the first, second and third AC / DC conversion modules are respectively connected to their respective controllers, and the controller includes a PFC module current sampler, a PFC module voltage sampler, a positive and negative bus voltage sampler, a DCDC module output current sampler, and a DCDC module output voltage sampler; the output end of the positive and negative bus voltage sampler is connected to the subtrahend input end of a first subtractor, the minuend end of the first subtractor is connected to the bus voltage setting value Vpfc_ref, the output end of the first subtractor is connected to a first PID regulator, the output end of the first PID regulator is connected to an input end of a first multiplier, the other input end of the first multiplier is connected to the PFC module voltage sampler, the output end of the first multiplier is connected to the minuend input end of a second subtractor, the minuend input end of the second subtractor is connected to the PFC module current sampler, and the output end of the second subtractor is connected to the PFC module voltage sampler. The output end of the DCDC module is connected to the input end of the second PID regulator, the output end of the second PID regulator is connected to the first PWM controller, and the first PWM controller controls the PFC module; the voltage sampler at the output end of the DCDC module is connected to the subtrahend end of the third subtractor, the minuend end of the third subtractor is connected to the output voltage setting value Vout_ref, the output end of the third subtractor is connected to the input end of the third PID regulator, and the output end of the third PID regulator is connected to an input end of the minuend extractor; the current sampler at the output end of the DCDC module is connected to the subtrahend end of the fourth subtractor, the minuend end of the fourth subtractor is connected to the output current setting value Iout_ref, the output end of the fourth subtractor is connected to the input end of the fourth PID regulator, and the output end of the fourth PID regulator is connected to another input end of the minuend extractor; the output end of the minuend extractor is connected to the second PWM controller, and the second PWM controller controls the DCDC module.

[0013] In another design scheme, in single-phase working mode, the first, second and third AC / DC conversion modules are respectively connected to their respective controllers, and the controller includes a PFC module current sampler, a PFC module voltage sampler, a positive and negative bus voltage sampler, a DCDC module output current sampler, and a DCDC module output voltage sampler; the output end of the positive and negative bus voltage sampler is connected to the subtrahend input end of the first subtractor, the minuend end of the first subtractor is connected to the bus voltage setting value Vpfc_ref, the output end of the first subtractor is connected to the first PID regulator, the output end of the first PID regulator is connected to an input end of the first multiplier, the other input end of the first multiplier is connected to the PFC module voltage sampler, the output end of the first multiplier is connected to the minuend input end of the second subtractor, the subtrahend input end of the second subtractor is connected to the PFC module current sampler, and the second subtractor The output end of the DCDC module is connected to the input end of the second PID regulator, the output end of the second PID regulator is connected to the first PWM controller, and the first PWM controller controls the PFC module; the voltage sampler at the output end of the DCDC module is connected to the subtrahend end of the third subtractor, the minuend end of the third subtractor is connected to the output voltage setting value Vout_ref, the output end of the third subtractor is connected to the input end of the third PID regulator, the output end of the third PID regulator is connected to one input end of the minuend device, the other input end of the minuend device is connected to the output current setting value Iout_ref, the output end of the minuend device is connected to the minuend end of the fourth subtractor, the minuend end of the fourth subtractor is connected to the DCDC module output end current sampler, the output end of the fourth subtractor is connected to the input end of the fourth PID regulator, the output end of the fourth PID regulator is connected to the second PWM controller, and the second PWM controller controls the DCDC module.

[0014] The present invention also designs a control method for a single-phase and three-phase compatible charger control circuit that reduces electrolytic capacitance, which includes a single-phase working mode and a three-phase working mode; in the single-phase working mode, only the first AC-DC conversion module is put into operation; in the three-phase working mode, the first, second and third AC-DC conversion modules are put into operation.

[0015] In the single-phase working mode, the large capacitance capacitor C in the first AC-DC conversion module is Ebus With the small value capacitor C Fbus Enter parallel operation; in the three-phase working mode, let the large capacitance capacitor C Ebus Disconnect from parallel connection and do not put into operation.

[0016] In the three-phase working mode, the PFC module input current Iin_ac and the PFC module input voltage Vin_ac are sampled, and the DCDC module output current Iout and the DCDC module output voltage Vout are sampled; the DCDC module output current Iout and the DCDC module output voltage Vout are multiplied to obtain the output power, and the charging power setting value Poutreq is subtracted from the output power to obtain the power deviation value, and the power deviation value is passed through the first PID regulator to obtain the power loop output value, and the power loop output value is multiplied by the PFC module input voltage Vin_ac to obtain the current reference value, and the current reference value is subtracted from the input current Iin_ac to obtain the duty cycle adjustment value, and the duty cycle adjustment value is adjusted by the second PID regulator and sent to the first PWM controller, and the first PWM controller controls the PFC module.

[0017] The bus voltage Vpfc of the positive and negative bus is sampled, and the bus voltage Vpfc is subtracted from the bus voltage setting value Vpfc_ref to obtain a voltage deviation value, which is adjusted by the third PID regulator and sent to the second PWM controller, and the second PWM controller controls the DCDC module.

[0018] In a design scheme, in single-phase working mode, the bus voltage Vpfc of the positive and negative bus is sampled, and the bus voltage setting value Vpfc_ref is subtracted from the bus voltage Vpfc to obtain a voltage deviation value, and the voltage deviation value is adjusted by the first PID regulator and multiplied with the PFC module input voltage Vin_ac, and the obtained product is subtracted from the PFC module input current Iin_ac, and the obtained difference is adjusted by the second PID regulator and sent to the first PWM controller, and the PFC module is controlled by the first PWM controller; the DCDC module output current Iout and the DCDC module output voltage Vout are sampled, and the DCDC module output voltage Vout is subtracted from the output voltage setting value Vout_ref, and the obtained difference is adjusted by the third PID regulator and sent to the min-getter; the DCDC module output current Iout is subtracted from the output current setting value Iout_ref, and the obtained difference is adjusted by the fourth PID regulator and sent to the min-getter; the min-getter sends the smaller of the two values ​​to the second PWM controller, and the second PWM controller controls the DCDC module.

[0019] In another design scheme, in single-phase working mode, the bus voltage Vpfc of the positive and negative buses is sampled, and the bus voltage setting value Vpfc_ref is subtracted from the bus voltage Vpfc to obtain a voltage deviation value, and the voltage deviation value is adjusted by the first PID regulator and multiplied with the PFC module input voltage Vin_ac, and the obtained product is subtracted from the PFC module input current Iin_ac, and the obtained difference is adjusted by the second PID regulator and sent to the first PWM controller, and the PFC module is controlled by the first PWM controller; the DCDC module output current Iout and the DCDC module output voltage Vout are sampled, and the DCDC module output voltage Vout is subtracted from the output voltage setting value Vout_ref, and the obtained difference is adjusted by the third PID regulator and sent to the min-max device; the min-max device compares it with the output current setting value Iout_ref, and subtracts the smaller value of the two values ​​from the DCDC module output current Iout, and the obtained difference is adjusted by the fourth PID regulator and sent to the second PWM controller, and the DCDC module is controlled by the second PWM controller.

[0020] The single-phase working mode and the three-phase working mode both include a charging state and an inverter state.

[0021] The beneficial effect of the technical solution provided by the present invention is that the present invention can reduce the use of electrolytic capacitors while meeting single-phase and three-phase input compatibility, and can reduce the use of electrolytic capacitors by about 2 / 3, thereby greatly improving the power density of the charger, increasing the life of the charger, reducing the size of the charger, and at the same time suppressing the output charging current ripple to maintain stable charging performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention is described in detail below with reference to the embodiments and accompanying drawings, wherein:

[0023] Figure 1 This is a schematic diagram of an existing single-phase and three-phase compatible charger;

[0024] Figure 2 This is a schematic diagram of the existing ACDC conversion charging module;

[0025] Figure 3 It is a schematic diagram comparing input voltage and current, input power and output power in the existing single-phase working mode;

[0026] Figure 4 This is a schematic diagram of the main circuit of a preferred embodiment of the present invention;

[0027] Figure 5 The capacitor C is a preferred embodiment of the present invention. Ebus Schematic diagram of series control switch;

[0028] Figure 6It is a schematic diagram of the control circuit in the three-phase working mode of the present invention;

[0029] Figure 7 It is a schematic diagram of a control circuit of an embodiment of the present invention in a single-phase working mode;

[0030] Figure 8 It is a schematic diagram of a control circuit of another embodiment of the present invention in a single-phase working mode;

[0031] Fig. 9 It is a schematic diagram comparing input voltage and current, input power and output power in the three-phase working mode of the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0033] The present invention discloses a single-phase three-phase compatible charger control circuit for reducing electrolytic capacitors. Figure 4 The main circuit diagram shown in FIG. 1 includes the first, second and third AC / DC conversion modules connected to the three phase lines of the power grid respectively, and the output ends of the first, second and third AC / DC conversion modules are connected in parallel and then connected to the battery; the bus capacitor of the first AC / DC conversion module adopts a large-capacitance bus capacitor, and the bus capacitor of the second and third AC / DC conversion modules adopts a small-capacitance bus capacitor C Fbus ; In the single-phase working mode, only the first AC-DC conversion module is put into operation; in the three-phase working mode, the first, second and third AC-DC conversion modules are all put into operation.

[0034] The first, second and third AC / DC conversion modules all include a PFC module and a DCDC module, wherein the PFC module and the DCDC module are connected via a positive bus and a negative bus; a small-capacitance bus capacitor C is connected in parallel between the positive and negative bus of the first AC / DC conversion module. Fbus And large value capacitor C Ebus A small bus capacitor C is provided between the positive and negative busbars of the second and third AC / DC conversion modules. Fbus .

[0035] The large capacitance capacitor C Ebus Electrolytic capacitors are used, and the small-capacitance bus capacitor C Fbus Use film capacitors or ceramic capacitors.

[0036] From the above description and attached Figure 4It can be seen that the circuit structures of the first AC / DC conversion module, the first AC / DC conversion module and the second AC / DC conversion module are basically the same. The first AC / DC conversion module includes an electrolytic capacitor, and the other two modules do not include an electrolytic capacitor. In the three-phase working mode, the three modules all control the output power to be consistent with the input power, and finally output a stable DC power. When working in single phase, the first AC / DC conversion module works in a traditional way, inputs AC power and outputs DC power. The retained electrolytic capacitor smoothes the power difference and reduces the output ripple current. In this way, while meeting the single-phase and three-phase input compatibility, the electrolytic capacitor can be reduced by about 2 / 3, thereby greatly improving the power density of the charger, increasing the life of the charger, reducing the size of the charger, and at the same time suppressing the output charging current ripple and maintaining stable charging performance.

[0037] See also Figure 5 In the preferred embodiment shown, the large capacitance capacitor C Ebus A control switch S is connected in series, and the control switch S is controlled by the controller; in the single-phase working mode, the control switch S is closed; in the three-phase working mode, the control switch S is disconnected. In the single-phase working mode, the capacitor CEbus and the bus capacitor CFbus are connected in parallel and put into operation; in the three-phase working mode, the capacitor CEbus is disconnected from the parallel connection and is not put into operation. After adding the control switch S, in the three-phase working mode, the capacitance in the three-phase circuit is symmetrical, and the operation is more stable. Figure 7 The figure shows the comparison of input voltage and current, input power and output power in the three-phase working mode of the present invention.

[0038] See also Figure 6The schematic diagram of the control circuit of the preferred embodiment is shown. In the three-phase working mode, the first, second and third AC-DC conversion modules are respectively connected to their respective controllers, and the controller includes a PFC module current sampler, a PFC module voltage sampler, a DCDC module output current sampler, and a DCDC module output voltage sampler; the DCDC module output current sampler and the DCDC module output voltage sampler are connected to two input ends of the first multiplier, the output end of the first multiplier is connected to the subtrahend input end of the first subtractor, and the minuend input end of the first subtractor is connected to the charging power setting value, the output end of the first subtractor is connected to the first PID regulator, the output end of the first PID regulator is connected to one input end of the second multiplier, and the other input end of the second multiplier is connected to the PFC module voltage sampler, the output end of the second multiplier is connected to the minuend input end of the second subtractor, the minuend input end of the second subtractor is connected to the PFC module current sampler, the output end of the second subtractor is connected to the input end of the second PID regulator, and the output end of the second PID regulator is connected to the first PWM controller, and the first PWM controller controls the PFC module. The controller includes a positive and negative bus voltage sampler, the output end of the positive and negative bus voltage sampler is connected to the subtrahend end of the third subtractor, the minuend end of the third subtractor is connected to the bus voltage setting value Vpfc_ref, the output end of the third subtractor is connected to the input end of the third PID regulator, the output end of the third PID regulator is connected to the second PWM controller, and the second PWM controller controls the DCDC module.

[0039] See also Figure 7 In the single-phase working mode of one embodiment shown, the first, second and third AC-DC conversion modules are respectively connected to respective controllers, and the controller includes a PFC module current sampler, a PFC module voltage sampler, a positive and negative bus voltage sampler, a DCDC module output end current sampler, and a DCDC module output end voltage sampler;

[0040] The output end of the positive and negative bus voltage sampler is connected to the subtrahend input end of the first subtractor, the minuend end of the first subtractor is connected to the bus voltage setting value Vpfc_ref, the output end of the first subtractor is connected to the first PID regulator, the output end of the first PID regulator is connected to an input end of the first multiplier, the other input end of the first multiplier is connected to the PFC module voltage sampler, the output end of the first multiplier is connected to the minuend input end of the second subtractor, the minuend input end of the second subtractor is connected to the PFC module current sampler, the output end of the second subtractor is connected to the input end of the second PID regulator, the output end of the second PID regulator is connected to the first PWM controller, and the first PWM controller controls the PFC module;

[0041] The voltage sampler at the output end of the DCDC module is connected to the subtrahend end of the third subtractor, the minuend end of the third subtractor is connected to the output voltage setting value Vout_ref, the output end of the third subtractor is connected to the input end of the third PID regulator, and the output end of the third PID regulator is connected to one input end of the minutor; the current sampler at the output end of the DCDC module is connected to the subtrahend end of the fourth subtractor, the minuend end of the fourth subtractor is connected to the output current setting value Iout_ref, the output end of the fourth subtractor is connected to the input end of the fourth PID regulator, and the output end of the fourth PID regulator is connected to another input end of the minutor; the output end of the minutor is connected to the second PWM controller, and the second PWM controller controls the DCDC module.

[0042] See also Figure 8 In another embodiment shown, in single-phase working mode, the first, second and third AC / DC conversion modules are respectively connected to respective controllers, and the controller includes a PFC module current sampler, a PFC module voltage sampler, a positive and negative bus voltage sampler, a DCDC module output end current sampler, and a DCDC module output end voltage sampler;

[0043] The output end of the positive and negative bus voltage sampler is connected to the subtrahend input end of the first subtractor, the minuend end of the first subtractor is connected to the bus voltage setting value Vpfc_ref, the output end of the first subtractor is connected to the first PID regulator, the output end of the first PID regulator is connected to an input end of the first multiplier, the other input end of the first multiplier is connected to the PFC module voltage sampler, the output end of the first multiplier is connected to the minuend input end of the second subtractor, the minuend input end of the second subtractor is connected to the PFC module current sampler, the output end of the second subtractor is connected to the input end of the second PID regulator, the output end of the second PID regulator is connected to the first PWM controller, and the first PWM controller controls the PFC module;

[0044] The voltage sampler at the output end of the DCDC module is connected to the minuend end of the third subtractor, the minuend end of the third subtractor is connected to the output voltage setting value Vout_ref, the output end of the third subtractor is connected to the input end of the third PID regulator, the output end of the third PID regulator is connected to one input end of the minuend device, the other input end of the minuend device is connected to the output current setting value Iout_ref, the output end of the minuend device is connected to the minuend end of the fourth subtractor, the minuend end of the fourth subtractor is connected to the DCDC module output end current sampler, the output end of the fourth subtractor is connected to the input end of the fourth PID regulator, the output end of the fourth PID regulator is connected to the second PWM controller, and the second PWM controller controls the DCDC module.

[0045] The present invention also discloses a control method for a single-phase and three-phase compatible charger control circuit for reducing electrolytic capacitance, which includes a single-phase working mode and a three-phase working mode; in the single-phase working mode, only the first AC / DC conversion module is put into operation; in the three-phase working mode, the first, second and third AC / DC conversion modules are put into operation.

[0046] In the single-phase working mode, the large capacitance capacitor C in the first AC-DC conversion module is Ebus With the small value capacitor C Fbus Enter parallel operation; in the three-phase working mode, let the large capacitance capacitor C Ebus Disconnect from parallel connection and do not put into operation.

[0047] In single-phase operation mode, the main capacitor C Ebus Perform energy storage filtering on the ripple current. In the three-phase working mode, the PFC module input current Iin_ac and the PFC module input voltage Vin_ac are sampled, and the DCDC module output current Iout and the DCDC module output voltage Vout are sampled; the DCDC module output current Iout and the DCDC module output voltage Vout are multiplied to obtain the output power, and the charging power setting value Poutreq is used to subtract the output power to obtain the power deviation value, and the power deviation value is passed through the first PID regulator to obtain the power loop output value (the power loop output value is proportional to the input average current, and this loop bandwidth is much smaller than the input AC frequency, so this power loop output is a quasi-constant value proportional to the input demand current.), the power loop output value is multiplied by the PFC module input voltage Vin_ac to obtain a current reference value, and the current reference value is subtracted from the input current Iin_ac to obtain a duty cycle adjustment value, and the duty cycle adjustment value is adjusted by the second PID regulator and sent to the first PWM controller, and the first PWM controller controls the PFC module so that the input current is consistent with the expected current, and this current loop is relatively fast to obtain a higher THD.

[0048] See also Figure 6 The schematic diagram of the control circuit of the preferred embodiment is shown. In the three-phase working mode, the bus voltage Vpfc of the positive and negative buses is sampled, and the bus voltage Vpfc is subtracted from the bus voltage setting value Vpfc_ref to obtain a voltage deviation value. The voltage deviation value is adjusted by the third PID regulator and then sent to the second PWM controller. The second PWM controller controls the DCDC module to control the power conversion of the DCDC module so that the PFC voltage remains unchanged, thereby allowing the energy input to the Cbus to be transmitted to the subsequent stage in time to charge the battery.

[0049] When single-phase operation is used, a control loop (voltage outer loop, current inner loop and voltage and current loop in parallel) is often used to ensure that the output voltage and current are constant. Figure 7 In the single-phase working mode of an embodiment shown, the bus voltage Vpfc of the positive and negative buses is sampled, and the bus voltage Vpfc is subtracted from the bus voltage setting value Vpfc_ref to obtain a voltage deviation value. The voltage deviation value is adjusted by the first PID regulator and multiplied with the PFC module input voltage Vin_ac. The obtained product is subtracted from the PFC module input current Iin_ac, and the obtained difference is adjusted by the second PID regulator and sent to the first PWM controller, and the PFC module is controlled by the first PWM controller; the DCDC module output current Iout and the DCDC module output voltage Vout are sampled, and the DCDC module output voltage Vout is subtracted from the output voltage setting value Vout_ref. The obtained difference is adjusted by the third PID regulator and sent to the minimizer; the DCDC module output current Iout is subtracted from the output current setting value Iout_ref, and the obtained difference is adjusted by the fourth PID regulator and sent to the minimizer; the minimizer sends the smaller value of the two values ​​to the second PWM controller, and the second PWM controller controls the DCDC module.

[0050] See also Figure 8 In another embodiment shown in the single-phase working mode, the bus voltage Vpfc of the positive and negative buses is sampled, and the bus voltage setting value Vpfc_ref is subtracted from the bus voltage Vpfc to obtain a voltage deviation value, and the voltage deviation value is adjusted by the first PID regulator and multiplied with the PFC module input voltage Vin_ac, and the obtained product is subtracted from the PFC module input current Iin_ac, and the obtained difference is adjusted by the second PID regulator and sent to the first PWM controller, and the first PWM controller controls the PFC module; the DCDC module output current Iout and the DCDC module output voltage Vout are sampled, and the DCDC module output voltage Vout is subtracted from the output voltage setting value Vout_ref, and the obtained difference is adjusted by the third PID regulator and sent to the min-max device; the min-max device compares it with the output current setting value Iout_ref, and subtracts the smaller value of the two values ​​from the DCDC module output current Iout, and the obtained difference is adjusted by the fourth PID regulator and sent to the second PWM controller, and the second PWM controller controls the DCDC module.

[0051] In a preferred embodiment, the single-phase working mode and the three-phase working mode both include a charging state and an inverter state.

[0052] The above embodiments are for illustration only and are not intended to be limiting. Any equivalent modifications or changes made thereto without departing from the spirit and scope of the present application shall be included in the scope of the claims of the present application.

Claims

1. A single-phase and three-phase compatible charger control circuit for reducing electrolytic capacitors, characterized in that: The invention comprises a first, a second and a third AC / DC conversion module respectively connected to the three phase lines of the power grid, wherein the output ends of the first, the second and the third AC / DC conversion modules are connected in parallel and then connected to the battery; the bus capacitor of the first AC / DC conversion module adopts a large-capacitance bus capacitor, and the bus capacitor of the second and the third AC / DC conversion modules adopts a small-capacitance bus capacitor C Fbus ; In the single-phase working mode, only the first AC-DC conversion module is put into operation; in the three-phase working mode, the first, second and third AC-DC conversion modules are all put into operation; In the three-phase working mode, the first, second and third AC-DC conversion modules are respectively connected to respective controllers, and the controller includes a PFC module current sampler, a PFC module voltage sampler, a DCDC module output end current sampler, and a DCDC module output end voltage sampler; The DCDC module output end current sampler and the DCDC module output end voltage sampler are connected to two input ends of the first multiplier, the output end of the first multiplier is connected to the subtrahend input end of the first subtractor, the minuend input end of the first subtractor is connected to the charging power setting value, the output end of the first subtractor is connected to the first PID regulator, the output end of the first PID regulator is connected to an input end of the second multiplier, the other input end of the second multiplier is connected to the PFC module voltage sampler, the output end of the second multiplier is connected to the minuend input end of the second subtractor, the minuend input end of the second subtractor is connected to the PFC module current sampler, the output end of the second subtractor is connected to the input end of the second PID regulator, the output end of the second PID regulator is connected to the first PWM controller, and the first PWM controller controls the PFC module; The controller includes a positive and negative bus voltage sampler, the output end of the positive and negative bus voltage sampler is connected to the subtrahend end of the third subtractor, the minuend end of the third subtractor is connected to the bus voltage setting value Vpfc_ref, the output end of the third subtractor is connected to the input end of the third PID regulator, the output end of the third PID regulator is connected to the second PWM controller, and the second PWM controller controls the DCDC module.

2. The single-phase and three-phase compatible charger control circuit with reduced electrolytic capacitor according to claim 1, characterized in that: The first, second and third AC / DC conversion modules all include a PFC module and a DCDC module, wherein the PFC module and the DCDC module are connected via a positive bus and a negative bus; a small-capacitance bus capacitor C is connected in parallel between the positive and negative bus of the first AC / DC conversion module. Fbus And large value capacitor C Ebus A small bus capacitor C is provided between the positive and negative busbars of the second and third AC / DC conversion modules. Fbus .

3. The single-phase and three-phase compatible charger control circuit with reduced electrolytic capacitor as claimed in claim 2, characterized in that: The large capacitance capacitor C Ebus Electrolytic capacitors are used, and the small-capacitance bus capacitor C Fbus Use film capacitors or ceramic capacitors.

4. The single-phase and three-phase compatible charger control circuit with reduced electrolytic capacitors as claimed in claim 3, characterized in that: The large capacitance capacitor C Ebus A control switch S is connected in series and is controlled by a controller; in a single-phase working mode, the control switch S is closed; in a three-phase working mode, the control switch S is opened.

5. The single-phase and three-phase compatible charger control circuit with reduced electrolytic capacitor as claimed in claim 1, characterized in that: In the single-phase working mode, the first, second and third AC / DC conversion modules are respectively connected to their respective controllers, and the controller includes a PFC module current sampler, a PFC module voltage sampler, a positive and negative bus voltage sampler, a DCDC module output end current sampler, and a DCDC module output end voltage sampler; The output end of the positive and negative bus voltage sampler is connected to the subtrahend input end of the first subtractor, the minuend end of the first subtractor is connected to the bus voltage setting value Vpfc_ref, the output end of the first subtractor is connected to the first PID regulator, the output end of the first PID regulator is connected to an input end of the first multiplier, the other input end of the first multiplier is connected to the PFC module voltage sampler, the output end of the first multiplier is connected to the minuend input end of the second subtractor, the minuend input end of the second subtractor is connected to the PFC module current sampler, the output end of the second subtractor is connected to the input end of the second PID regulator, the output end of the second PID regulator is connected to the first PWM controller, and the first PWM controller controls the PFC module; The voltage sampler at the output end of the DCDC module is connected to the subtrahend end of the third subtractor, the minuend end of the third subtractor is connected to the output voltage setting value Vout_ref, the output end of the third subtractor is connected to the input end of the third PID regulator, and the output end of the third PID regulator is connected to one input end of the minutor; the current sampler at the output end of the DCDC module is connected to the subtrahend end of the fourth subtractor, the minuend end of the fourth subtractor is connected to the output current setting value Iout_ref, the output end of the fourth subtractor is connected to the input end of the fourth PID regulator, and the output end of the fourth PID regulator is connected to another input end of the minutor; the output end of the minutor is connected to the second PWM controller, and the second PWM controller controls the DCDC module.

6. The single-phase and three-phase compatible charger control circuit with reduced electrolytic capacitors as claimed in claim 1, characterized in that: In the single-phase working mode, the first, second and third AC / DC conversion modules are respectively connected to their respective controllers, and the controller includes a PFC module current sampler, a PFC module voltage sampler, a positive and negative bus voltage sampler, a DCDC module output end current sampler, and a DCDC module output end voltage sampler; The output end of the positive and negative bus voltage sampler is connected to the subtrahend input end of the first subtractor, the minuend end of the first subtractor is connected to the bus voltage setting value Vpfc_ref, the output end of the first subtractor is connected to the first PID regulator, the output end of the first PID regulator is connected to an input end of the first multiplier, the other input end of the first multiplier is connected to the PFC module voltage sampler, the output end of the first multiplier is connected to the minuend input end of the second subtractor, the minuend input end of the second subtractor is connected to the PFC module current sampler, the output end of the second subtractor is connected to the input end of the second PID regulator, the output end of the second PID regulator is connected to the first PWM controller, and the first PWM controller controls the PFC module; The voltage sampler at the output end of the DCDC module is connected to the minuend end of the third subtractor, the minuend end of the third subtractor is connected to the output voltage setting value Vout_ref, the output end of the third subtractor is connected to the input end of the third PID regulator, the output end of the third PID regulator is connected to one input end of the minuend device, the other input end of the minuend device is connected to the output current setting value Iout_ref, the output end of the minuend device is connected to the minuend end of the fourth subtractor, the minuend end of the fourth subtractor is connected to the DCDC module output end current sampler, the output end of the fourth subtractor is connected to the input end of the fourth PID regulator, the output end of the fourth PID regulator is connected to the second PWM controller, and the second PWM controller controls the DCDC module.

7. A control method for a single-phase or three-phase compatible charger control circuit with reduced electrolytic capacitance according to any one of claims 1 to 6, characterized in that: Including single-phase working mode and three-phase working mode; In the single-phase working mode, only the first AC-DC conversion module is put into operation; in the three-phase working mode, the first, second and third AC-DC conversion modules are put into operation.

8. The control method of a single-phase or three-phase compatible charger control circuit with reduced electrolytic capacitors as claimed in claim 7, characterized in that: In the single-phase working mode, the large capacitance capacitor C in the first AC-DC conversion module is Ebus With the small value capacitor C Fbus Enter parallel operation; in the three-phase working mode, let the large capacitance capacitor C Ebus Disconnect from parallel connection and do not put into operation.

9. The control method of a single-phase or three-phase compatible charger control circuit with reduced electrolytic capacitors as claimed in claim 8, characterized in that: In three-phase operation mode, The PFC module input current Iin_ac and the PFC module input voltage Vin_ac are sampled, and the DCDC module output current Iout and the DCDC module output voltage Vout are sampled; The output current Iout of the DCDC module is multiplied by the output voltage Vout of the DCDC module to obtain the output power, the output power is subtracted from the charging power setting value Poutreq to obtain the power deviation value, the power deviation value is passed through the first PID regulator to obtain the power loop output value, the power loop output value is multiplied by the input voltage Vin_ac of the PFC module to obtain the current reference value, the input current Iin_ac is subtracted from the current reference value to obtain the duty cycle adjustment value, the duty cycle adjustment value is adjusted by the second PID regulator and then sent to the first PWM controller, and the first PWM controller controls the PFC module; The bus voltage Vpfc of the positive and negative bus is sampled, and the bus voltage Vpfc is subtracted from the bus voltage setting value Vpfc_ref to obtain a voltage deviation value, which is adjusted by the third PID regulator and sent to the second PWM controller, and the second PWM controller controls the DCDC module.

10. The control method of a single-phase and three-phase compatible charger control circuit with reduced electrolytic capacitors as claimed in claim 8, characterized in that: In single-phase operation mode, The bus voltage Vpfc of the positive and negative busbars is sampled, and the bus voltage Vpfc is subtracted from the bus voltage setting value Vpfc_ref to obtain a voltage deviation value. The voltage deviation value is adjusted by the first PID regulator and multiplied by the PFC module input voltage Vin_ac. The obtained product is subtracted from the PFC module input current Iin_ac. The obtained difference is adjusted by the second PID regulator and sent to the first PWM controller, and the first PWM controller controls the PFC module; The output current Iout and the output voltage Vout of the DCDC module are sampled, and the output voltage Vout of the DCDC module is subtracted from the output voltage setting value Vout_ref. The obtained difference is adjusted by the third PID regulator and sent to the minimizer; the output current Iout of the DCDC module is subtracted from the output current setting value Iout_ref, and the obtained difference is adjusted by the fourth PID regulator and sent to the minimizer; the minimizer sends the smaller value of the two values ​​to the second PWM controller, and the second PWM controller controls the DCDC module.

11. The control method of a single-phase and three-phase compatible charger control circuit with reduced electrolytic capacitors as claimed in claim 8, characterized in that: In single-phase operation mode, The bus voltage Vpfc of the positive and negative busbars is sampled, and the bus voltage Vpfc is subtracted from the bus voltage setting value Vpfc_ref to obtain a voltage deviation value. The voltage deviation value is adjusted by the first PID regulator and multiplied by the PFC module input voltage Vin_ac. The obtained product is subtracted from the PFC module input current Iin_ac. The obtained difference is adjusted by the second PID regulator and sent to the first PWM controller, and the first PWM controller controls the PFC module; The output current Iout and the output voltage Vout of the DCDC module are sampled, and the output voltage Vout of the DCDC module is subtracted from the output voltage setting value Vout_ref. The obtained difference is adjusted by the third PID regulator and sent to the minimizer; the minimizer compares it with the output current setting value Iout_ref, and subtracts the smaller value of the two values ​​from the output current Iout of the DCDC module. The obtained difference is adjusted by the fourth PID regulator and sent to the second PWM controller, and the DCDC module is controlled by the second PWM controller.

12. The control method of a single-phase or three-phase compatible charger control circuit with reduced electrolytic capacitors as claimed in claim 7, characterized in that: The single-phase working mode and the three-phase working mode both include a charging state and an inversion state.

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