A single-phase power input control method based on three-phase Vienna PFC topology

Abstract

The present invention discloses a single-phase power input control method based on a three-phase Vienna PFC topology. The control method is based on a single-phase power input circuit of a three-phase Vienna PFC topology. The sampling point of the input current is replaced to the three-phase power supply. The total current is calculated as the sum of the main current and the filter branch current. The total current is then brought into a single-cycle control algorithm to calculate the duty cycle value for controlling the input current of each phase, thereby achieving control of the output voltage and the input current. It can be seen from the waveform that the oscillation of the input inductor current and the output voltage is significantly suppressed, and the THD is also improved to a certain extent.

Description

Technical Field

[0001] The present application relates to the field of switching power supply circuits, and in particular to a single-phase power input control method based on a three-phase Vienna PFC topology. Background Art

[0002] The three-phase Vienna circuit is widely used in three-phase high-power power supplies due to its simple structure, small voltage stress of switching devices, and high efficiency. Single-cycle control does not require a phase-locked loop to generate a current reference. Its nonlinear carrier characteristics enable the power converter to respond quickly to load transients, and can achieve low current distortion and high power factor. It is widely used in three-phase Vienna topology.

[0003] The three-phase Vienna input filter circuit is generally designed as a two-stage π-type filter. The CLC π-type filter has a low-pass filtering function, which can effectively filter out high-frequency components, suppress input voltage ripple, reduce input line losses, and improve the electromagnetic compatibility of the module. However, the frequency response of the CLC filter has a resonance peak at the resonant frequency, which will cause system instability, especially when the power grid quality is poor or multiple power supplies are used in parallel.

[0004] As the power requirements of power supplies increase, the requirements for power supply parallel connection are also getting higher and higher. After the power supplies are connected in parallel, the input inductor currents of the three phases A, B, and C will oscillate to varying degrees. The traditional solution is to add a resistor in series with the filter capacitor branch to increase the impedance during resonance and suppress resonance, but the series resistor will weaken the high-frequency attenuation capability of the CLC filter. Therefore, it is necessary to find a new method to suppress the oscillation of the input inductor current. Summary of the invention

[0005] The present application aims at the problem of input inductor current oscillation of the three-phase Vienna input circuit used in the switching power supply, and provides a single-phase power input control method based on the three-phase Vienna PFC topology, which can effectively suppress the oscillation of the input inductor current.

[0006] The technical solution of the present invention to solve the above technical problems is as follows:

[0007] A single-phase power input control method based on a three-phase Vienna PFC topology, the single-phase power input control method adopts a single-phase power input circuit based on a three-phase Vienna PFC topology, the single-phase power input circuit includes a three-phase input unit, a three-phase Vienna PFC unit and a PFC control unit, the three-phase input unit is used to access a three-phase AC power supply of a power grid; the three-phase Vienna PFC unit includes a first inductor LA, a second inductor LB, a third inductor LC, a filter circuit unit and a PFC circuit unit, the first inductor LA, the second inductor LB, the third inductor LC, the filter circuit unit and the PFC circuit unit One end of LB and the third inductor LC are respectively connected to the power output terminals A phase, B phase and C phase of the three-phase input unit, forming the A phase input main path, the B phase input main path and the C phase input main path respectively; the PFC circuit unit includes a first branch switch tube, a second branch switch tube and a third branch switch tube, wherein the first branch switch tube, the second branch switch tube and the third branch switch tube are respectively connected to the A phase input main path, the B phase input main path and the C phase input main path; the PFC control unit includes a voltage input terminal, a current input terminal and a control signal output terminal;

[0008] The single-phase power input control method comprises the following steps:

[0009] (1) Collect the total current Ia, Ib, Ic of each phase and the total voltage Va, Vb, Vc of each phase at the output end of the three-phase input unit; and collect the voltage at the output end of the PFC circuit unit , , and calculate ,in, ; Collect the inductor currents Ia1, Ib1, and Ic1 at the input end of each phase input main circuit;

[0010] Collect the current Ia2, Ib2, and Ic2 of each phase filter branch at the input end of the filter circuit unit;

[0011] Moreover, the total current per phase = the inductor current per phase + the filter branch current per phase.

[0012] (2) The current and voltage information collected in step (1) are transmitted to the current input terminal and voltage input terminal corresponding to the PFC control unit respectively, and the maximum value of each phase total current Ia, Ib, and Ic is calculated. and minimum value Then calculate the harmonic current value according to the formula :

[0013] ;

[0014] (3) Calculate the voltage loop output voltage based on the PI control algorithm , and its calculation formula is:

[0015] ;

[0016] ;

[0017] ;

[0018] in, is the voltage loop proportional error, is the voltage loop integral error, It is the voltage loop reference, and its value is 650V; is the proportional coefficient, the value is 6000; is the integral coefficient, the value is 10;

[0019] (4) Calculate the output duty cycle Duty of each phase switch tube:

[0020] ;

[0021] in, is the experience value, the value is 3000; is the total input current of each phase of the three-phase power supply, is the total voltage of each phase of the three-phase power supply, n represents a, b, c;

[0022] The calculated output duty cycle of each phase switch tube is output through the control signal output terminal corresponding to the PFC control unit to control the on and off of the corresponding branch switch tube of the PFC circuit unit, thereby controlling the output voltage , And the inductor currents Ia1, Ib1, and Ic1 at the input end of each phase input main circuit.

[0023] Furthermore, the PFC control unit has three signal output terminals, which are respectively connected to the source electrodes of the first branch switch tube, the second branch switch tube and the third branch switch tube, and are used to load PWM pulse signals to the source electrodes of the first branch switch tube, the second branch switch tube and the third branch switch tube to control the duty cycle of each branch switch tube, and the voltage input terminal of the PFC control unit corresponds to the total voltage Va, Vb, Vc of each phase and the output voltage of the PFC circuit unit respectively. , The current input terminals correspond to the total currents Ia, Ib, and Ic of each phase respectively.

[0024] Further, the filter circuit unit includes a first branch filter circuit, a second branch filter circuit and a third branch filter circuit, and the first branch filter circuit, the second branch filter circuit and the third branch filter circuit are all capacitor filter circuits, and the input ends of the first branch filter circuit, the second branch filter circuit and the third branch filter circuit are respectively connected to the corresponding ends of the power supply output ends A phase, B phase and C phase of the three-phase input unit, and the output ends are connected in parallel and connected to the ground through the filter capacitor.

[0025] The beneficial effect of the above further scheme is: using π-type filtering, the differential mode interference first passes through the differential mode component of the π-type filtering, mainly filtering out the differential mode interference of the low-frequency part, and then passes through the common mode component of the π-type filtering, mainly filtering out the common mode interference of the high-frequency part, effectively suppressing electromagnetic interference.

[0026] Furthermore, the rectifier circuit unit is a three-phase bridge rectifier circuit, including a first branch bridge arm circuit, a second branch bridge arm circuit and a third branch bridge arm circuit; the first branch bridge arm circuit includes a first diode D4 and a second diode D5 connected in series, wherein the anode of the first diode D4 and the cathode of the second diode D5 are connected, and the connection point is correspondingly connected to the output end of the first inductor LA; the second branch bridge arm circuit includes a third diode D6 and a fourth diode D7 connected in series, wherein the anode of the third diode D6 and the cathode of the fourth diode D7 are connected, and the connection point is correspondingly connected to the output end of the second inductor LB; the third branch bridge arm circuit includes a fifth diode D8 and a sixth diode D9 connected in series, wherein the anode of the fifth diode D8 and the cathode of the sixth diode D9 are connected, and the connection point is correspondingly connected to the output end of the third inductor LC.

[0027] Further, the first branch switch tube includes a first switch tube A1 and a second switch tube A2, and the sources of the first switch tube A1 and the second switch tube A2 are connected in pairs, the gates are connected in pairs, the drain of the first switch tube A1 is connected to the A-phase input main circuit, and the drain of the second switch tube A2 is connected to the BUSN of the DC output end; the second branch switch tube includes a third switch tube B1 and a fourth switch tube B2, and the sources of the third switch tube B1 and the fourth switch tube B2 are connected in pairs, the gates are connected in pairs, the drain of the third switch tube B1 is connected to the B-phase input main circuit, and the drain of the fourth switch tube B2 is connected to the BUSN of the DC output end; the third branch switch tube includes a fifth switch tube C1 and a sixth switch tube C2, and the sources of the fifth switch tube C1 and the sixth switch tube C2 are connected in pairs, the gates are connected in pairs, the drain of the fifth switch tube C1 is connected to the C-phase input main circuit, and the drain of the sixth switch tube C2 is connected to the BUSN of the DC output end.

[0028] The above further solution has the following beneficial effects: adopting a three-level structure, each group of switches shares a group of drivers, the driving circuit is simple, and each switch tube withstands a voltage of half the bus voltage, which facilitates device selection and reduces losses.

[0029] Furthermore, the total current of each phase collected in the step (1) can be collected by using a corresponding current transformer, and the current transformer is connected in series to the power output terminals A phase, B phase, and C phase of the three-phase input unit, respectively. The total voltage of each phase can be collected by using a voltage transformer, and the voltage transformer is connected in parallel to the power output terminals A phase, B phase, and C phase of the three-phase input unit, respectively.

[0030] The beneficial effect of the above further solution is that the current transformer isolates the input power from the current sampling signal, reduces the interference of the input power noise on the sampling signal, and has a higher sampling accuracy.

[0031] Furthermore, the step (1) further includes collecting the inductor currents Ia1, Ib1, Ic1 at the input end of each phase input main circuit; and collecting the filter branch currents Ia2, Ib2, Ic2 at the input end of the filter circuit unit;

[0032] Moreover, the total current per phase = the inductor current per phase + the filter branch current per phase.

[0033] The beneficial effect of the above further solution is that the sampled input current includes the main circuit current Ia1 and the branch current Ia2, and is closer to the real input current value.

[0034] Furthermore, the collected inductor currents Ia1, Ib1, and Ic1 at the input end of each phase input main circuit can be collected using a current transformer, and the current transformer is respectively connected to the other end of the inductor of each phase input main circuit; the collected filter branch currents of each phase can be collected using a current transformer, and the current transformer is respectively connected to the input end of each branch filter circuit.

[0035] The beneficial effect of the above further solution is that the current transformer isolates the input power from the current sampling signal, reduces the interference of the input power noise on the sampling signal, and has a higher sampling accuracy.

[0036] Furthermore, the PFC circuit output voltage collected in step (1) , Both can be collected by voltage transformer, and the output voltage The voltage transformer is connected to the cathodes of the first diode D4, the third diode D6 and the fifth diode D8 of the three-phase bridge rectifier circuit for collection; the output voltage The voltage transformer is connected to the anodes of the second diode D5, the fourth diode D7 and the sixth diode D9 of the three-phase bridge rectifier circuit for collection.

[0037] The beneficial effect of the above further solution is: the output voltage is accurately controlled by sampling the output voltage to ensure the stability of the output voltage.

[0038] The present application adopts the above technical solution, which has at least the following beneficial effects:

[0039] The hardware circuit of the present invention is a single-phase power input circuit based on the three-phase Vienna PFC topology. A new input filtering and sampling circuit is proposed herein. Through this circuit and a single-cycle control scheme, the resonance problem caused by poor power grid quality or the parallel use of multiple power supplies can be solved without connecting a resistor in series with the filter capacitor branch.

[0040] The present invention changes the sampling point of the input current to Ia, and the sampled input current includes the main circuit current Ia1 and the branch current Ia2, which is closer to the real input current value. Then it is brought into the single-cycle control algorithm to calculate the duty cycle value of the A-phase input current, realize the control of the output voltage and input current, and significantly suppress the oscillation of the input inductor current and the output voltage. At the same time, the THD is also improved to a certain extent, increasing the stability of the system, while retaining the high-frequency attenuation capability of the CLC filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a hardware structure diagram of the present invention;

[0042] Figure 2 It is a topological structure diagram of the hardware filter circuit of the present invention;

[0043] Figure 3 A topological structure diagram of a three-phase Vienna PFC unit circuit of the present invention;

[0044] Figure 4 It is a structural diagram of a PFC control unit of the present invention;

[0045] Figure 5 This is a switch tube control diagram of the present invention when the A phase input inductor current peaks;

[0046] Figure 6 This is a switch control diagram of the present invention when the A-phase input inductor current is in the valley;

[0047] Figure 7 This is a switch control diagram of the present invention when the A-phase input inductor current is at zero point;

[0048] Figure 8 A single inductor current waveform diagram and an output voltage waveform diagram of the present invention using the existing method;

[0049] Fig. 9 The total input current and synthetic current waveform diagram of the new method used in the present invention;

[0050] Fig.10 The waveform diagram of input inductor current and output voltage using the new method of the present invention;

[0051] Fig.11 This is a waveform diagram of the B-phase and C-phase input inductor current using the new method of the present invention. DETAILED DESCRIPTION

[0052] Now, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood that the embodiments shown and described in the accompanying drawings are only exemplary and are intended to explain the principles and spirit of the present invention, rather than to limit the scope of the present invention.

[0053] See also Figures 1 to 11 The present invention is used for switching power supply. Without changing the existing three-phase Vienna hardware, there is no need to adopt the traditional method of connecting resistors in series in the filter capacitor branch. The resonance problem caused by poor grid quality or the parallel use of multiple power supplies can be solved by simply changing the current collection point method and control method.

[0054] like Figure 1 , Figure 2 and Figure 3 As shown, it is the hardware structure block diagram and circuit topology diagram adopted by the present invention. The input is a three-phase power supply with a voltage of 220V per phase and 50Hz. The stable output is 650V, the full load power is 2500W, and the full load is achieved in 0.03s. Lavin, Lbvin, and Lcvin are the inductors connected in series in the simulated parallel state. The hardware circuit is a single-phase electrical input circuit based on a three-phase Vienna PFC topology, wherein the single-phase electrical input circuit comprises a three-phase input unit, a three-phase Vienna PFC unit and a PFC control unit, wherein the three-phase input unit is used to access a three-phase AC power supply of a power grid; the three-phase Vienna PFC unit comprises a first inductor LA, a second inductor LB, a third inductor LC, a filter circuit unit and a PFC circuit unit, wherein one end of the first inductor LA, the second inductor LB and the third inductor LC are respectively connected to the power output terminals A phase, B phase and C phase of the three-phase input unit, respectively forming an A phase input main path, a B phase input main path and a C phase input main path; the PFC circuit unit comprises a first branch switch tube, a second branch switch tube and a third branch switch tube, wherein the first branch switch tube, the second branch switch tube and the third branch switch tube are respectively connected to the A phase input main path, the B phase input main path and the C phase input main path; the PFC control unit comprises a voltage input terminal, a current input terminal and a control signal output terminal.

[0055] Specifically, the PFC control unit has three signal output ends, which are respectively connected to the source electrodes of the first branch switch tube, the second branch switch tube and the third branch switch tube, and are used to load PWM pulse signals to the source electrodes of the first branch switch tube, the second branch switch tube and the third branch switch tube to control the duty cycle of each branch switch tube. The voltage input end of the PFC control unit corresponds to the total voltage Va, Vb, Vc of each phase and the output end voltage of the PFC circuit unit, and the current input end corresponds to the total current Ia, Ib, Ic of each phase.

[0056] like Figure 2As shown, in the embodiment of the present invention, the filter circuit unit adopts π-type filtering, and the filter circuit unit includes a first branch filter circuit, a second branch filter circuit and a third branch filter circuit, and the first branch filter circuit, the second branch filter circuit and the third branch filter circuit are all capacitor filter circuits, and the input ends of the first branch filter circuit, the second branch filter circuit and the third branch filter circuit are respectively connected to the corresponding ends of the power output ends of the three-phase input unit, the A phase, the B phase and the C phase, and the output ends are connected in parallel and connected to the ground through the filter capacitor. Compared with the existing three-phase Vienna hardware conditions, the filter circuit hardware of the present invention does not require a series resistor, and only needs to connect an equivalent capacitor to each branch, thereby saving costs.

[0057] By using the above filtering circuit unit, the differential mode interference first passes through the differential mode component of the π-type filter, mainly filtering out the differential mode interference of the low-frequency part, and then passes through the common mode component of the π-type filter, mainly filtering out the common mode interference of the high-frequency part, effectively suppressing electromagnetic interference.

[0058] like Figure 3 As shown, in the embodiment of the present invention, the rectifier circuit unit is a three-phase bridge rectifier circuit, including a first branch bridge arm circuit, a second branch bridge arm circuit and a third branch bridge arm circuit; the first branch bridge arm circuit includes a first diode D4 and a second diode D5 connected in series, wherein the anode of the first diode D4 and the cathode of the second diode D5 are connected, and the connection point is correspondingly connected to the output end of the first inductor LA; the second branch bridge arm circuit includes a third diode D6 and a fourth diode D7 connected in series, wherein the anode of the third diode D6 and the cathode of the fourth diode D7 are connected, and the connection point is correspondingly connected to the output end of the second inductor LB; the third branch bridge arm circuit includes a fifth diode D8 and a sixth diode D9 connected in series, wherein the anode of the fifth diode D8 and the cathode of the sixth diode D9 are connected, and the connection point is correspondingly connected to the output end of the third inductor LC.

[0059] In the embodiment of the present invention, the first branch switch tube includes a first switch tube A1 and a second switch tube A2, and the sources of the first switch tube A1 and the second switch tube A2 are connected in pairs, the gates are connected in pairs, the drain of the first switch tube A1 is connected to the A-phase input main circuit, and the drain of the second switch tube A2 is connected to the BUSN of the DC output terminal; the second branch switch tube includes a third switch tube B1 and a fourth switch tube B2, and the sources of the third switch tube B1 and the fourth switch tube B2 are connected in pairs, the gates are connected in pairs, the drain of the third switch tube B1 is connected to the B-phase input main circuit, and the drain of the fourth switch tube B2 is connected to the BUSN of the DC output terminal; the third branch switch tube includes a fifth switch tube C1 and a sixth switch tube C2, and the sources of the fifth switch tube C1 and the sixth switch tube C2 are connected in pairs, the gates are connected in pairs, the drain of the fifth switch tube C1 is connected to the C-phase input main circuit, and the drain of the sixth switch tube C2 is connected to the BUSN of the DC output terminal.

[0060] The first branch switch tube, the second branch switch tube and the third branch switch tube adopt a three-level structure, each group of switches shares a set of drivers, and the drive circuit is simple. The voltage of each switch tube is half of the bus voltage, which is convenient for device selection and reduces losses.

[0061] It should be noted that: the first switch tube A1, the second switch tube A2, the third switch tube B1, the fourth switch tube B2, the fifth switch tube C1 and the sixth switch tube C2 are metal oxide semiconductor transistors (MOSFET), but other types of electronically controlled switching devices, such as bipolar junction transistors (BJT) and insulated gate transistors (IGBT) and other switch tubes can also be used as switch tubes of this embodiment; the above 6 switch tubes have the same structure, and generally use MOS tubes.

[0062] Based on the above hardware circuit, the present invention provides a single-phase power input control method based on a three-phase Vienna PFC topology, comprising the following steps:

[0063] (1) Collect the total current Ia, Ib, Ic of each phase and the total voltage Va, Vb, Vc of each phase at the output end of the three-phase input unit; the total current of each phase collected in the specific circuit can be collected by using the corresponding current transformer, and the current transformer is respectively connected to the output end of the A-phase input main circuit, the B-phase input main circuit and the C-phase input main circuit of the three-phase input unit; the total voltage of each phase can be collected by using a voltage transformer, and the voltage transformer is respectively connected to the output end of the A-phase input main circuit, the B-phase input main circuit and the C-phase input main circuit of the three-phase input unit.

[0064] The main inductor currents Ia1, Ib1, and Ic1 of each phase at the main input end are collected; the main currents Ia1, Ib1, and Ic1 of each phase collected in the specific circuit can be collected by current transformers, and the current transformers are respectively connected to the output ends of the first inductor LA, the second inductor LB, and the third inductor LC.

[0065] The filter circuit unit input end is used to collect the current Ia2, Ib2, and Ic2 of each phase filter branch. The current of each phase branch collected in the specific circuit can be collected by a current transformer, and the current transformer is respectively connected to the input end of the first branch filter circuit, the second branch filter circuit, and the third branch filter circuit.

[0066] Collect the voltage at the output of the PFC circuit , And calculate ,in, ; The PFC circuit output voltage collected in its specific circuit , Both can be collected by voltage transformer, and the output voltage The voltage transformer is connected to the cathodes of the first diode D4, the third diode D6 and the fifth diode D8 of the three-phase bridge rectifier circuit for collection; the output voltage The voltage transformer is connected to the anodes of the second diode D5, the fourth diode D7 and the sixth diode D9 of the three-phase bridge rectifier circuit for collection.

[0067] In the present invention, the current collection is not limited to the above-mentioned current transformer, and other current samplers in the prior art may also be used; similarly, the voltage collection is not limited to the above-mentioned voltage transformer, and other voltage samplers in the prior art may also be used; no further details will be given here.

[0068] (2) Based on the total currents Ia, Ib, and Ic collected in step (1), find their maximum value and minimum value , and then calculate at least one (preferably 2-3) harmonic current value according to the formula :

[0069] ;

[0070] (3) Calculate the voltage loop output voltage based on the PI control algorithm , and its calculation formula is:

[0071] ;

[0072] ;

[0073] ;

[0074] in, is the voltage loop proportional error, is the voltage loop integral error, It is the voltage loop reference, and its value is 650V; is the proportional coefficient, the value is 6000; is the integral coefficient, the value is 10;

[0075] (4) Calculate the output duty cycle of each phase according to the duty cycle formula:

[0076] ;

[0077] in, is the experience value, the value is 3000; is the total input current of each phase of the three-phase power supply, is the total voltage of each phase of the three-phase power supply, n represents a, b, c;

[0078] (5) The calculated output duty cycle of each phase switch tube is output through the control signal output terminal corresponding to the PFC control unit to control the on and off of the corresponding branch switch tube of the PFC circuit unit, thereby controlling the output voltage , And the inductor currents Ia1, Ib1, and Ic1 at the input end of each phase input main circuit.

[0079] like Figure 5 , Figure 6 , Figure 7 These are the switch tube control conditions at the peak, trough, and zero points of the A-phase input inductor current. When the switch tube is closed, the input inductor current increases, and when it is disconnected, the input inductor current decreases.

[0080] The above method is used to simulate the input current and output voltage of phase A. The simulation results are shown below:

[0081] Figure 8 The input current waveform and output voltage waveform when the main inductor current Ia1 is used for calculation. Since the traditional current sampling method only samples the main current Ia1, the solution to oscillation is to increase the resistance value in the branch. However, increasing the resistance value will affect the suppression of high-frequency noise by the branch filter capacitor, so the setting of the resistance value will be limited. The input A phase current and output voltage simulation are as follows: Figure 8 As shown, it can be seen from the waveform that the input current and output voltage still have different degrees of oscillation.

[0082] like Fig. 9The figure shows the current waveform when the sampling point of the input current is changed to Ia and the total current Ia is used for calculation. It can be seen from the figure that Ia=Ia1+Ia2, that is, the sampled input current includes the main circuit inductor current Ia1 and the branch current Ia2, which is closer to the actual input current value.

[0083] Fig.10 The input current waveform and output voltage waveform when the total current Ia is used for calculation are then brought into the single-cycle control algorithm to calculate the duty cycle value for controlling the input current of phase A, and the output voltage and input current are controlled. From the waveform, it can be seen that the oscillation of the input current and output voltage is significantly suppressed, and the THD is also improved to a certain extent. Therefore, it can be concluded that through the above method provided by the present invention, the input current and output voltage waveforms of phase A do reduce oscillation, increase the stability of the system, and retain the high-frequency attenuation capability of the CLC filter.

[0084] The above simulation only simulates the input current and output voltage of phase A. Similarly, phases B and C can also be simulated in the same way. The specific results are as follows: Fig.11 shown.

[0085] It can be seen from the above simulation results that the control method of the present invention realizes the control of the output voltage and the input current, significantly suppresses the oscillation of the input inductor current and the output voltage, and increases the stability of the system.

[0086] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A single-phase power input control method based on a three-phase Vienna PFC topology, characterized in that: The single-phase power input control method adopts a single-phase power input circuit based on a three-phase Vienna PFC topology, wherein the single-phase power input circuit includes a three-phase input unit, a three-phase Vienna PFC unit and a PFC control unit, wherein the three-phase input unit is used to access a three-phase AC power supply of a power grid; the three-phase Vienna PFC unit includes a first inductor LA, a second inductor LB, a third inductor LC, a filter circuit unit and a PFC circuit unit, wherein one end of the first inductor LA, the second inductor LB and the third inductor LC are respectively connected to the power output terminals A phase, B phase and C phase of the three-phase input unit, respectively forming an A phase input main path, a B phase input main path and a C phase input main path; the PFC circuit unit includes a first branch switch tube, a second branch switch tube and a third branch switch tube, wherein the first branch switch tube, the second branch switch tube and the third branch switch tube are respectively connected to the A phase input main path, the B phase input main path and the C phase input main path; the PFC control unit includes a voltage input terminal, a current input terminal and a control signal output terminal; The single-phase power input control method comprises the following steps: (1) Collect the total current Ia, Ib, Ic of each phase and the total voltage Va, Vb, Vc of each phase at the output end of the three-phase input unit; and collect the voltage at the output end of the PFC circuit unit , , and calculate ,in, ； (2) The current and voltage information collected in step (1) are transmitted to the current input terminal and voltage input terminal corresponding to the PFC control unit respectively, and the maximum value of each phase total current Ia, Ib, and Ic is calculated. and minimum value Then calculate the harmonic current value according to the formula : ； (3) Calculate the voltage loop output voltage based on the PI control algorithm , and its calculation formula is: ； ； ； in, is the voltage loop proportional error, is the voltage loop integral error, is the voltage loop reference; is the proportionality coefficient; is the integration coefficient; (4) Calculate the output duty cycle Duty of each phase switch tube: ； in, is the experience value; is the total input current of each phase of the three-phase power supply, is the total voltage of each phase of the three-phase power supply, n represents a, b, c; (5) The calculated output duty cycle of each phase switch tube is output through the control signal output terminal corresponding to the PFC control unit to control the on and off of the corresponding branch switch tube of the PFC circuit unit, thereby controlling the output voltage , and the inductor currents Ia1, Ib1, Ic1 at the input terminals of each phase input main circuit; The first branch switch tube includes a first switch tube A1 and a second switch tube A2, and the sources of the first switch tube A1 and the second switch tube A2 are connected in pairs, the gates are connected in pairs, the drain of the first switch tube A1 is connected to the A-phase input main circuit, and the drain of the second switch tube A2 is connected to the BUSN of the DC output terminal; the second branch switch tube includes a third switch tube B1 and a fourth switch tube B2, and the sources of the third switch tube B1 and the fourth switch tube B2 are connected in pairs, the gates are connected in pairs, the drain of the third switch tube B1 is connected to the B-phase input main circuit, and the drain of the fourth switch tube B2 is connected to the BUSN of the DC output terminal; the third branch switch tube includes a fifth switch tube C1 and a sixth switch tube C2, and the sources of the fifth switch tube C1 and the sixth switch tube C2 are connected in pairs, the gates are connected in pairs, the drain of the fifth switch tube C1 is connected to the C-phase input main circuit, and the drain of the sixth switch tube C2 is connected to the BUSN of the DC output terminal; The PFC control unit has three signal output terminals, which are respectively connected to the source electrodes of the first branch switch tube, the second branch switch tube and the third branch switch tube, and are used to load PWM pulse signals to the source electrodes of the first branch switch tube, the second branch switch tube and the third branch switch tube to control the duty cycle of each branch switch tube. The voltage input terminal of the PFC control unit corresponds to the total voltage Va, Vb, Vc of each phase and the output voltage of the PFC circuit unit. , The current input terminals correspond to the total currents Ia, Ib, and Ic of each phase respectively.

2. The single-phase power input control method according to claim 1, characterized in that: The three-phase Vienna PFC unit further includes a rectifying circuit unit.

3. The single-phase power input control method according to claim 2, characterized in that: The rectifier circuit unit is a three-phase bridge rectifier circuit, including a first branch bridge arm circuit, a second branch bridge arm circuit and a third branch bridge arm circuit; the first branch bridge arm circuit includes a first diode D4 and a second diode D5 connected in series, wherein the anode of the first diode D4 and the cathode of the second diode D5 are connected, and the connection point is correspondingly connected to the output end of the first inductor LA; the second branch bridge arm circuit includes a third diode D6 and a fourth diode D7 connected in series, wherein the anode of the third diode D6 and the cathode of the fourth diode D7 are connected, and the connection point is correspondingly connected to the output end of the second inductor LB; the third branch bridge arm circuit includes a fifth diode D8 and a sixth diode D9 connected in series, wherein the anode of the fifth diode D8 and the cathode of the sixth diode D9 are connected, and the connection point is correspondingly connected to the output end of the third inductor LC.

4. The single-phase power input control method according to claim 1, characterized in that: The filter circuit unit includes a first branch filter circuit, a second branch filter circuit and a third branch filter circuit, and the first branch filter circuit, the second branch filter circuit and the third branch filter circuit are all capacitor filter circuits, the input ends of the first branch filter circuit, the second branch filter circuit and the third branch filter circuit are respectively connected to the corresponding ends of the power supply output ends A phase, B phase and C phase of the three-phase input unit, and the output ends are connected in parallel and connected to the ground through the filter capacitor.

5. The single-phase power input control method according to claim 1, characterized in that: The total current of each phase in step (1) can be collected by using a corresponding current transformer, and the current transformer is connected in series to the power output terminals A phase, B phase, and C phase of the three-phase input unit respectively; Furthermore, the total voltage of each phase in step (1) can be collected by using a voltage transformer, and the voltage transformer is respectively connected in parallel to the power output terminals A phase, B phase, and C phase of the three-phase input unit.

6. The single-phase power input control method according to claim 1, characterized in that: The step (1) also includes collecting the inductor currents Ia1, Ib1, Ic1 at the input end of each phase input main circuit; and collecting the filter branch currents Ia2, Ib2, Ic2 of each phase at the input end of the filter circuit unit; and the total current of each phase = the inductor current of each phase + the filter branch current of each phase.

7. The single-phase power input control method according to claim 6, characterized in that: The collected inductor currents Ia1, Ib1, and Ic1 at the input end of each phase input main circuit can be collected by using a current transformer, and the current transformer is respectively connected to the other end of the inductor of each phase input main circuit; the collected filter branch currents of each phase can be collected by using a current transformer, and the current transformer is respectively connected to the input end of each branch filter circuit.

8. The single-phase power input control method according to claim 3, characterized in that: The PFC circuit output voltage collected in step (1) , Voltage transformers can be used for data collection, and the output voltage The voltage transformer is connected to the cathodes of the first diode D4, the third diode D6 and the fifth diode D8 of the three-phase bridge rectifier circuit for collection; the output voltage The voltage transformer is connected to the anodes of the second diode D5, the fourth diode D7 and the sixth diode D9 of the three-phase bridge rectifier circuit for collection.

Images