Three-phase rectifier single-period power factor correction circuit and correction method

Abstract

The invention provides a single-period power factor correction circuit and method for a three-phase rectifier. The single-period power factor correction circuit comprises a three-phase power supply, a three-phase boost inductor, a rectifier bridge circuit, a switching circuit, a first capacitor, a second capacitor, a first resistor, a second resistor, a third resistor and a detection circuit, the three-phase power supply is connected with the first end of the three-phase boost inductor, the second end of the three-phase boost inductor is connected with the first end of the rectifier bridge circuit, and the second end of the rectifier bridge circuit is connected with the input end of the switching circuit. The output end of the switching circuit is connected with the first end of the first resistor, the first end of the second resistor, the first end of the first capacitor and the first end of the second capacitor. And the detection circuit is used for detecting voltage values among the three-phase power supply, the three-phase boost inductor, the switching circuit, the first capacitor and the second capacitor, and realizing power factor correction according to the voltage values. The method is high in universality, simple in parameter adjustment, capable of adapting to different power controllers, fast in response to power grid voltage change and more suitable for air conditioner application scenes.

Description

Technical Field

[0001] The present invention relates to the field of circuit technology, and in particular to a three-phase rectifier single-cycle power factor correction circuit and a correction method. Background Art

[0002] The three-phase active power factor correction (APFC) method based on VIENNA rectifier is mainly used in the fields of electric vehicle charging piles, power supplies, etc. In the field of refrigeration / HVAC, the three-phase PFC scheme of three-phase power supply devices such as three-phase variable frequency air conditioners in production is mainly passive PFC scheme. The passive PFC circuit is mainly composed of passive devices such as reactors (or specific sub-resonance suppression circuits in which reactors are connected in parallel with non-polarized capacitors) and rectifier diodes, and there are no active control devices (power switching devices such as IGBTs and MOSFETs).

[0003] The power factor of a three-phase passive PFC can usually only be corrected to around 0.8-0.85, and the total harmonic distortion (THD) can only be reduced to around 30%, which makes it difficult to meet the current harmonic standard restrictions (IEC61000-2-2 requires THD of public grid access points to be less than 8%, and IEC61000-2-4 requires THD of factory-level grid access points to be less than 10%). The reactor has many wiring connections, occupies a large space, is not easy to assemble, and has complex wiring, making EMI difficult to solve. Excessive wiring poses the risk of terminal detachment.

[0004] If VIENNA-APFC is applied to air conditioners and other devices, the control parameters of the commonly used dual-loop control method need to be adjusted according to the system, which has many problems such as many parameters, difficult adjustment, and poor matching. Summary of the invention

[0005] The invention provides a three-phase rectifier single-cycle power factor correction circuit, aiming to solve the problems of multiple parameters, difficult adjustment and poor matching of the existing three-phase rectifier single-cycle power factor correction circuit.

[0006] In a first aspect, an embodiment of the present invention provides a three-phase rectifier single-cycle power factor correction circuit, comprising: a three-phase power supply, a three-phase boost inductor, a rectifier bridge circuit, a switch circuit, a first capacitor, a second capacitor, a first resistor, a second resistor, a third resistor, and a detection circuit;

[0007] The three-phase power supply is respectively connected to the first end of the three-phase boost inductor, the second end of the three-phase boost inductor is connected to the first end of the rectifier bridge circuit, the second end of the rectifier bridge circuit is connected to the input end of the switch circuit, the output end of the switch circuit is respectively connected to the first end of the first resistor, the first end of the second resistor, the first end of the first capacitor and the first end of the second capacitor, the second end of the first capacitor is connected to the second end of the first resistor, the second end of the second capacitor is connected to the second end of the second resistor, and the two ends of the third resistor are respectively connected to the second end of the first resistor and the second end of the second resistor; the detection circuit is used to detect the voltage value between the three-phase power supply, the three-phase boost inductor, the switch circuit and the first capacitor and the second capacitor, and realize power factor correction according to the voltage value.

[0008] Preferably, the three-phase boost inductor includes a first inductor, a second inductor and a third inductor, the first end of the first inductor, the second end of the second inductor and the first end of the third inductor are respectively connected to the three-phase power supply, and the second end of the first inductor, the second end of the second inductor and the second end of the third inductor are respectively connected to the first end of the rectifier bridge circuit.

[0009] Preferably, the rectifier bridge circuit includes a first diode, a second diode, a third diode, a fourth diode, a fifth diode and a sixth diode;

[0010] The cathode of the first diode is respectively connected to the cathode of the third diode, the cathode of the fifth diode and the second end of the first capacitor, the anode of the first diode is respectively connected to the second end of the first inductor and the cathode of the second diode, the anode of the third diode is respectively connected to the second end of the second inductor and the cathode of the fourth diode, the anode of the fifth diode is respectively connected to the second end of the third inductor and the cathode of the sixth diode; the anode of the second diode is respectively connected to the anode of the fourth diode, the anode of the sixth diode and the second end of the second capacitor;

[0011] The input end of the switch circuit is respectively connected between the first diode and the second diode, between the third diode and the fourth diode, and between the fifth diode and the sixth diode.

[0012] Preferably, the switch circuit includes a first bidirectional switch, a second bidirectional switch, a third bidirectional switch, a fourth bidirectional switch, a fifth bidirectional switch and a sixth bidirectional switch;

[0013] A first end of the first bidirectional switch is connected to the first inductor, a second end of the first bidirectional switch is connected to a first end of the second bidirectional switch, and a second end of the second bidirectional switch is connected between a first end of the first capacitor and a first end of the second capacitor;

[0014] The first end of the third bidirectional switch is connected to the second inductor, and the second end of the third bidirectional switch is connected to the first end of the fourth bidirectional switch; the first end of the fifth bidirectional switch is connected to the third inductor, and the second end of the fifth bidirectional switch is connected to the first end of the sixth bidirectional switch; the second end of the second bidirectional switch is also connected to the second end of the fourth bidirectional switch and the second end of the sixth bidirectional switch, respectively.

[0015] Preferably, the detection circuit includes a control circuit, a voltage acquisition circuit and a PWM signal generating circuit; the control circuit is used to control the voltage acquisition circuit to respectively acquire the output voltages of the first inductor, the second inductor and the third inductor, and control the voltage acquisition circuit to output an electrical signal to the PWM signal generating circuit according to the output voltage; the PWM signal generating circuit generates a corresponding PWM signal and outputs it to the switching circuit, so as to control the on or off of the switching circuit.

[0016] In a second aspect, an embodiment of the present invention provides a three-phase VIENNA rectifier single-cycle power factor correction method, the correction method is implemented based on the above-mentioned three-phase rectifier single-cycle power factor correction circuit, and the correction method includes the following steps:

[0017] Step S1, obtaining the channel sampling input side line voltage of the three-phase power supply, and calculating the three-phase voltage according to the channel sampling input side line voltage;

[0018] Step S2, respectively collecting voltage values ​​of the first capacitor and the second capacitor, calculating a corresponding bus voltage according to the voltage values, and calculating a voltage step-up ratio through the bus voltage;

[0019] Step S3, obtaining the three-phase current of the three-phase boost inductor, and calculating the corresponding three-phase duty cycle according to the three-phase current and the corresponding boost ratio;

[0020] Step S4, calculating and obtaining a driving PWM signal of a switch circuit according to the three-phase voltage and the three-phase duty cycle;

[0021] Step S5: performing single-cycle correction control according to the driving PWM signal.

[0022] Compared with the prior art, the beneficial effect of the present invention lies in that the three-phase power supply is respectively connected to the first end of the three-phase boost inductor, the second end of the three-phase boost inductor is connected to the first end of the rectifier bridge circuit, the second end of the rectifier bridge circuit is connected to the input end of the switching circuit, the output end of the switching circuit is respectively connected to the first end of the first resistor, the first end of the second resistor, the first end of the first capacitor and the first end of the second capacitor, the second end of the first capacitor is connected to the second end of the first resistor, the second end of the second capacitor is connected to the second end of the second resistor, and the two ends of the third resistor are respectively connected to the second end of the first resistor and the second end of the second resistor; the detection circuit is used to detect the voltage value between the three-phase power supply, the three-phase boost inductor, the switching circuit and the first capacitor and the second capacitor, and realize power factor correction according to the voltage value; such a setting does not require loop control, has strong compatibility, simple parameter adjustment, can be adapted to different power controllers, responds quickly to changes in grid voltage, and is more suitable for air-conditioning application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be described in detail below in conjunction with the accompanying drawings. The above and other aspects of the present invention will become clearer and easier to understand through the detailed description made in conjunction with the following drawings. In the accompanying drawings:

[0024] Figure 1 It is a system circuit diagram of a three-phase rectifier single-cycle power factor correction circuit provided by an embodiment of the present invention;

[0025] Figure 2 is a local amplification circuit diagram provided by an embodiment of the present invention;

[0026] Figure 3 is a circuit diagram of a detection circuit provided by an embodiment of the present invention;

[0027] Figure 4 yes Figure 3 Circuit diagram of the control circuit;

[0028] Figure 5 yes Figure 3 Circuit diagram of voltage acquisition circuit;

[0029] Figure 6 yes Figure 3 Circuit diagram of a PWM signal generating circuit;

[0030] Figure 7 The present invention provides a flow chart of a single-cycle power factor correction method for a three-phase rectifier.

[0031] In the figure, 1. rectifier bridge circuit, 2. switch circuit, 3. detection circuit, 31. control circuit, 32. voltage acquisition circuit, 33. PWM signal generating circuit. 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 intended to limit the present invention.

[0033] First, combined with the Figure 1-Figure 6 As shown, an embodiment of the present invention provides a three-phase rectifier single-cycle power factor correction circuit, including: a three-phase power supply (Ua, Ub, Uc), a three-phase boost inductor (La, Lb, Lc), a rectifier bridge circuit 1, a switch circuit 2, a first capacitor C1, a second capacitor C2, a first resistor R1, a second resistor R2, a third resistor RL and a detection circuit 3;

[0034] The three-phase power supply is respectively connected to the first end of the three-phase boost inductor, the second end of the three-phase boost inductor is connected to the first end of the rectifier bridge circuit 1, the second end of the rectifier bridge circuit 1 is connected to the input end of the switch circuit 2, the output end of the switch circuit 2 is respectively connected to the first end of the first resistor R1, the first end of the second resistor R2, the first end of the first capacitor C1 and the first end of the second capacitor C2, the second end of the first capacitor C1 is connected to the second end of the first resistor R1, the second end of the second capacitor C2 is connected to the second end of the second resistor R2, and the two ends of the third resistor RL are respectively connected to the second end of the first resistor R1 and the second end of the second resistor R2; the detection circuit 3 is used to detect the voltage value between the three-phase power supply, the three-phase boost inductor, the switch circuit 2 and the first capacitor C1 and the second capacitor C2, and realize power factor correction according to the voltage value.

[0035] Specifically, the three-phase power supply is respectively connected to the first end of the three-phase boost inductor, the second end of the three-phase boost inductor is connected to the first end of the rectifier bridge circuit 1, the second end of the rectifier bridge circuit 1 is connected to the input end of the switch circuit 2, and the output end of the switch circuit 2 is respectively connected to the first end of the first resistor R1, the first end of the second resistor R2, the first end of the first capacitor C1 and the first end of the second capacitor C2, the second end of the first capacitor C1 is connected to the second end of the first resistor R1, the second end of the second capacitor C2 is connected to the second end of the second resistor R2, and the two ends of the third resistor RL are respectively connected to the second end of the first resistor R1 and the second end of the second resistor R2; the detection circuit 3 is used to detect the voltage value between the three-phase power supply, the three-phase boost inductor, the switch circuit 2 and the first capacitor C1 and the second capacitor C2, and realize power factor correction according to the voltage value; such a setting does not require loop control, has strong universality, simple parameter adjustment, can be adapted to different power controllers, responds quickly to grid voltage changes, and is more suitable for air-conditioning application scenarios.

[0036] In this embodiment, the three-phase boost inductor includes a first inductor La, a second inductor Lb and a third inductor Lc, the first end of the first inductor La, the second end of the second inductor Lb and the first end of the third inductor Lc are respectively connected to the three-phase power supply, and the second end of the first inductor La, the second end of the second inductor Lb and the second end of the third inductor Lc are respectively connected to the first end of the rectifier bridge circuit 1.

[0037] In this embodiment, the rectifier bridge circuit 1 includes a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5 and a sixth diode D6;

[0038] The cathode of the first diode D1 is respectively connected to the cathode of the third diode D3, the cathode of the fifth diode D5 and the second end of the first capacitor C1, the anode of the first diode D1 is respectively connected to the second end of the first inductor La and the cathode of the second diode D2, the anode of the third diode D3 is respectively connected to the second end of the second inductor Lb and the cathode of the fourth diode D4, the anode of the fifth diode D5 is respectively connected to the second end of the third inductor Lc and the cathode of the sixth diode D6; the anode of the second diode D2 is respectively connected to the anode of the fourth diode D4, the anode of the sixth diode D6 and the second end of the second capacitor C2;

[0039] The input end of the switch circuit 2 is respectively connected between the first diode D1 and the second diode D2 , between the third diode D3 and the fourth diode D4 , and between the fifth diode D5 and the sixth diode D6 .

[0040] The first diode D1 to the sixth diode D6 are all composed of fast recovery diodes FRD.

[0041] In this embodiment, the switch circuit 2 includes a first bidirectional switch T1, a second bidirectional switch T2, a third bidirectional switch T3, a fourth bidirectional switch T4, a fifth bidirectional switch T5 and a sixth bidirectional switch T6; three-phase bidirectional switches T1~T6, each phase bidirectional switch is composed of two IGBTs in a common emitter back-to-back form, using their inherent anti-parallel diodes to share drive signals, thereby reducing the difficulty of control and driving.

[0042] A first end of the first bidirectional switch T1 is connected to the first inductor La, a second end of the first bidirectional switch T1 is connected to a first end of the second bidirectional switch T2, and a second end of the second bidirectional switch T2 is connected between a first end of the first capacitor C1 and a first end of the second capacitor C2;

[0043] The first end of the third bidirectional switch T3 is connected to the second inductor Lb, and the second end of the third bidirectional switch T3 is connected to the first end of the fourth bidirectional switch T4; the first end of the fifth bidirectional switch T5 is connected to the third inductor Lc, and the second end of the fifth bidirectional switch T5 is connected to the first end of the sixth bidirectional switch T6; the second end of the second bidirectional switch T2 is also connected to the second end of the fourth bidirectional switch T4 and the second end of the sixth bidirectional switch T6, respectively.

[0044] In this embodiment, the detection circuit 3 includes a control circuit 31, a voltage acquisition circuit 32 and a PWM signal generating circuit 33; the control circuit 31 is used to control the voltage acquisition circuit 32 to respectively acquire the output voltages of the first inductor La, the second inductor Lb and the third inductor Lc, and control the voltage acquisition circuit 32 to output an electrical signal to the PWM signal generating circuit 33 according to the output voltage, and the PWM signal generating circuit 33 generates a corresponding PWM signal and outputs it to the switch circuit 2, so as to control the conduction or disconnection of the switch circuit 2.

[0045] In the specific implementation, three boost circuits are connected in Y shape and connected to a three-phase power supply; taking phase A as an example, when the current of phase A is greater than zero, the first bidirectional switch T1 of the forward direction in the bidirectional switch is turned on, and the first inductor La is charged; the first bidirectional switch T1 is turned off, the first diode D1 is turned on, and the first capacitor C1 is charged; when the current of phase A is less than zero, the second bidirectional switch T2 of the reverse direction in the bidirectional switch is turned on, and the first inductor La is charged; the second bidirectional switch T2 is turned off, the second diode D2 is turned on, and the second capacitor C2 is charged.

[0046] Second, combined with the Figure 1-Figure 7 As shown, an embodiment of the present invention provides a three-phase VIENNA rectifier single-cycle power factor correction method, the correction method is implemented based on the above-mentioned three-phase rectifier single-cycle power factor correction circuit, and the correction method includes the following steps:

[0047] Step S1, obtaining the channel sampling input side line voltage of the three-phase power supply, and calculating the three-phase voltage according to the channel sampling input side line voltage.

[0048] Among them, AD4 represents U a and U b Connected voltage, AD5 represents U a and U c Connected voltage; sampling input side line voltage U through AD4~AD5 channels ab / U ac , calculate the three-phase voltage U a / U b / U c .

[0049] Specifically, the input side line voltage U is sampled through the AD4~AD5 channels ab / U ac , calculate the three-phase voltage U a / U b / U c .

[0050]

[0051] Step S2, respectively collecting the voltage values ​​of the first capacitor and the second capacitor, calculating the corresponding bus voltage according to the voltage values, and calculating the boost ratio through the bus voltage.

[0052] Among them, the DC side electrolytic capacitor voltage Uc1 / Uc2 is sampled through AD6~AD7 channels, Uc1 is the first capacitor in step S2, Uc2 is the second capacitor in step S2, and the DC bus voltage Udc is calculated. The boost ratio Ka can be calculated through the target bus voltage.

[0053] Specifically, the DC side electrolytic capacitor voltage Uc1 / Uc2 is sampled through the AD6~AD7 channels to calculate the DC bus voltage U dc .

[0054] In order to reduce the difference between the actual bus voltage and the reference value, the boost ratio is generally adjusted through a closed-loop regulator, as shown in the following expression 3.2. That is, the reference voltage U dc_ref , minus the actual sample value U dc , the boost ratio Ka is obtained through the PI regulator and the limiter.

[0055] To ensure that the critical controllable state is not reached, the bus voltage reference value must be at least twice the peak value of the power supply voltage, and the boost ratio takes the minimum value:

[0056]

[0057] Among them U a_mag is the input AC voltage peak value, U a_mve is the average value of the input AC voltage.

[0058] To ensure that the voltage on a single capacitor does not exceed the withstand voltage (assuming 450V), the bus voltage reference value is generally a maximum of 700V, and the boost ratio takes the maximum value:

[0059]

[0060] Among them U a_rms is the effective value of the input AC voltage.

[0061] If the phase voltage effective value is as low as 150V, the bus voltage can be as high as 478V; if the phase voltage effective value is as high as 265V, the bus voltage can be as low as 750V. In the case of grid voltage fluctuations, the motor control requirements can be met without damaging the device.

[0062] Step S3, obtaining the three-phase current of the three-phase boost inductor, and calculating the corresponding three-phase duty cycle according to the three-phase current and the corresponding boost ratio.

[0063] Among them, the three-phase current ia / ib / ic on the input side is sampled through the AD1~AD3 channels, and the three-phase current combined with the boost ratio Ka can be used to calculate the three-phase duty cycle D A / D B / D C .

[0064] Specifically, the three-phase current i of the input side is sampled through channels AD1 to AD3 a / i b / i c , the three-phase current is calculated through a low-pass filter to obtain the average current I a_ave / I b_ave / I c_ave , the three-phase current polarity is calculated through the sign determination function sign(x), and finally the three-phase duty cycle is calculated according to the following formula.

[0065]

[0066] Where k1 is a coefficient between 0 and 1, sign(i x )(x=a,b,c) is the sign of the x-phase current, kx(x=a,b,c) is the x-phase voltage step-up ratio, I a _ave / I b _ave / I c _ave is the average value of three-phase current.

[0067] Step S4: Calculate and obtain a driving PWM signal of a switching circuit according to the three-phase voltage and the three-phase duty cycle.

[0068] The polarity is determined by the three-phase voltage Ua / Ub / Uc, and the PWM signal for driving the six IGBTs TI to T6 can be calculated by the three-phase duty ratio Da / Db / Dc.

[0069] Specifically, the three-phase duty cycle values ​​Da / Db / Dc calculated by the above steps are compared with the carrier signal (the high-frequency active PFC carrier is generally a triangle wave or sawtooth wave above 30KHz) to obtain the three-phase drive pulse signal S a / S b / S cAccording to the three-phase voltage polarity, the six IGBT drive signals of the rectifier are:

[0070]

[0071] Step S5: performing single-cycle correction control according to the driving PWM signal.

[0072] Specifically, the three-phase power supply is channel-sampled by acquiring the input side line voltage, and the three-phase voltage is calculated based on the channel-sampled input side line voltage; the voltage values ​​of the first capacitor and the second capacitor are respectively collected, and the corresponding bus voltage is calculated based on the voltage values, and the boost ratio is calculated through the bus voltage; the three-phase current of the three-phase boost inductor is acquired, and the corresponding three-phase duty cycle is calculated based on the three-phase current and the corresponding boost ratio; the drive PWM signal of the switching circuit is calculated based on the three-phase voltage and the three-phase duty cycle; and single-cycle correction control is performed based on the drive PWM signal. This setting does not require loop control, has strong versatility, simple parameter adjustment, can be adapted to different power controllers, responds quickly to grid voltage changes, and is more suitable for air-conditioning application scenarios.

[0073] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, article or device. In the absence of more restrictions, an element defined by the sentence "includes a ..." does not exclude the existence of other identical elements in the process, article or device including the element.

[0074] The embodiments of the present invention are described above in conjunction with the accompanying drawings. What is disclosed is only the preferred embodiment of the present invention. However, the present invention is not limited to the above-mentioned specific implementation manner. The above-mentioned specific implementation manner is only illustrative rather than restrictive. Under the enlightenment of the present invention, ordinary technicians in this field can also make many forms and equivalent changes without departing from the scope of protection of the purpose of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A three-phase rectifier single-cycle power factor correction circuit, characterized in that: include: A three-phase power supply, a three-phase boost inductor, a rectifier bridge circuit, a switch circuit, a first capacitor, a second capacitor, a first resistor, a second resistor, a third resistor and a detection circuit; The three-phase power supply is respectively connected to the first end of the three-phase boost inductor, the second end of the three-phase boost inductor is connected to the first end of the rectifier bridge circuit, the second end of the rectifier bridge circuit is connected to the input end of the switch circuit, the output end of the switch circuit is respectively connected to the first end of the first resistor, the first end of the second resistor, the first end of the first capacitor and the first end of the second capacitor, the second end of the first capacitor is connected to the second end of the first resistor, the second end of the second capacitor is connected to the second end of the second resistor, and the two ends of the third resistor are respectively connected to the second end of the first resistor and the second end of the second resistor; the detection circuit is used to detect the voltage value between the three-phase power supply, the three-phase boost inductor, the switch circuit and the first capacitor and the second capacitor, and realize power factor correction according to the voltage value.

2. The three-phase rectifier single-cycle power factor correction circuit according to claim 1, characterized in that: The three-phase boost inductor includes a first inductor, a second inductor and a third inductor, wherein the first end of the first inductor, the second end of the second inductor and the first end of the third inductor are respectively connected to the three-phase power supply, and the second end of the first inductor, the second end of the second inductor and the second end of the third inductor are respectively connected to the first end of the rectifier bridge circuit.

3. The three-phase rectifier single-cycle power factor correction circuit according to claim 2, characterized in that: The rectifier bridge circuit includes a first diode, a second diode, a third diode, a fourth diode, a fifth diode and a sixth diode; The cathode of the first diode is respectively connected to the cathode of the third diode, the cathode of the fifth diode and the second end of the first capacitor, the anode of the first diode is respectively connected to the second end of the first inductor and the cathode of the second diode, the anode of the third diode is respectively connected to the second end of the second inductor and the cathode of the fourth diode, the anode of the fifth diode is respectively connected to the second end of the third inductor and the cathode of the sixth diode; the anode of the second diode is respectively connected to the anode of the fourth diode, the anode of the sixth diode and the second end of the second capacitor; The input end of the switch circuit is respectively connected between the first diode and the second diode, between the third diode and the fourth diode, and between the fifth diode and the sixth diode.

4. The three-phase rectifier single-cycle power factor correction circuit as claimed in claim 3, characterized in that: The switch circuit includes a first bidirectional switch, a second bidirectional switch, a third bidirectional switch, a fourth bidirectional switch, a fifth bidirectional switch and a sixth bidirectional switch; A first end of the first bidirectional switch is connected to the first inductor, a second end of the first bidirectional switch is connected to a first end of the second bidirectional switch, and a second end of the second bidirectional switch is connected between a first end of the first capacitor and a first end of the second capacitor; The first end of the third bidirectional switch is connected to the second inductor, and the second end of the third bidirectional switch is connected to the first end of the fourth bidirectional switch; the first end of the fifth bidirectional switch is connected to the third inductor, and the second end of the fifth bidirectional switch is connected to the first end of the sixth bidirectional switch; the second end of the second bidirectional switch is also connected to the second end of the fourth bidirectional switch and the second end of the sixth bidirectional switch, respectively.

5. The three-phase rectifier single-cycle power factor correction circuit as claimed in claim 4, characterized in that: The detection circuit includes a control circuit, a voltage acquisition circuit and a PWM signal generating circuit; the control circuit is used to control the voltage acquisition circuit to respectively acquire the output voltages of the first inductor, the second inductor and the third inductor, and control the voltage acquisition circuit to output an electrical signal to the PWM signal generating circuit according to the output voltage; the PWM signal generating circuit generates a corresponding PWM signal and outputs it to the switch circuit, so as to control the on or off of the switch circuit.

6. A three-phase VIENNA rectifier single-cycle power factor correction method, characterized in that: The correction method is implemented based on the three-phase rectifier single-cycle power factor correction circuit according to any one of claims 1 to 5, and the correction method comprises the following steps: Step S1, obtaining the channel sampling input side line voltage of the three-phase power supply, and calculating the three-phase voltage according to the channel sampling input side line voltage; Step S2, respectively collecting voltage values ​​of the first capacitor and the second capacitor, calculating a corresponding bus voltage according to the voltage values, and calculating a voltage step-up ratio through the bus voltage; Step S3, obtaining the three-phase current of the three-phase boost inductor, and calculating the corresponding three-phase duty cycle according to the three-phase current and the corresponding boost ratio; Step S4, calculating and obtaining a driving PWM signal of a switch circuit according to the three-phase voltage and the three-phase duty cycle; Step S5: performing single-cycle correction control according to the driving PWM signal.

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