CN-122026735-A - Alternating control method and device of AC-DC converter and switching power supply

CN122026735ACN 122026735 ACN122026735 ACN 122026735ACN-122026735-A

Abstract

The invention discloses an interleaving control method, a control device and a switching power supply of an AC-DC converter, wherein the AC-DC converter is provided with an interleaving connection structure at a PFC stage, a high-frequency bridge arm of a first interleaving branch comprises switching tubes Q1 and Q2, a high-frequency bridge arm of a second interleaving branch comprises switching tubes Q3 and Q4, the first interleaving branch and the second interleaving branch share a power frequency bridge arm comprising switching tubes Q5 and Q6, the switching tubes Q1, Q3 and Q5 are upper bridge arm switching tubes, the switching tubes Q2, Q4 and Q6 are lower bridge arm switching tubes, the interleaving control method of the AC-DC converter comprises the steps of controlling the switching tubes Q1 and Q2 to be conducted complementarily, controlling the switching tubes Q3 and Q4 to be conducted complementarily, controlling the switching tubes Q5 and Q6 to be conducted complementarily by adopting a PWM modulation mode, the time of the switching tubes Q5 and Q1 to be conducted simultaneously is first time, the time of the switching tubes Q5 and Q3 to be conducted simultaneously is second time, and the first time is equal to the second time. The invention realizes the balance of PFC inductance currents of the staggered branches.

Inventors

YIN XIANGYANG
DU JUAN
WU HUI
LI YONGCHANG
Yin Zenghe
WANG ZHISHEN
LIU XIANG

Assignees

广州金升阳科技有限公司

Dates

Publication Date: 20260512
Application Date: 20241031

Claims (11)

1. The alternating control method of the AC-DC converter is characterized in that the alternating control method of the AC-DC converter comprises the following steps that the AC-DC converter is provided with an alternating connection structure at a PFC stage, a high-frequency bridge arm of a first alternating branch circuit comprises a switch tube Q1 and a switch tube Q2, a high-frequency bridge arm of a second alternating branch circuit comprises a switch tube Q3 and a switch tube Q4, the first alternating branch circuit and the second alternating branch circuit share a power frequency bridge arm comprising a switch tube Q5 and a switch tube Q6, the switch tube Q1, the switch tube Q3 and the switch tube Q5 are upper bridge arm switch tubes, and the switch tube Q2, the switch tube Q4 and the switch tube Q6 are lower bridge arm switch tubes, and the alternating control method of the AC-DC converter comprises the following steps: controlling the switching tube Q1 and the switching tube Q2 to conduct complementarily; controlling the switching tube Q3 and the switching tube Q4 to conduct complementarily; The PWM modulation mode is adopted to control the switching tube Q5 and the switching tube Q6 to be conducted complementarily, the time of the switching tube Q5 and the switching tube Q1 to be conducted simultaneously is a first time, the time of the switching tube Q5 and the switching tube Q3 to be conducted simultaneously is a second time, and the first time is equal to the second time.
2. The method for interleaving control of an AC-DC converter as claimed in claim 1, wherein the PWM signal of the switching tube Q1 is phase-shifted by 180 degrees with respect to the PWM signal of the switching tube Q3.
3. The method for interleaving control of an AC-DC converter as claimed in claim 2, wherein the first time is equal to the second time by controlling a phase shift Φ of the PWM signal of the switching transistor Q5 with respect to the PWM signal of the switching transistor Q1.
4. The method for interleaving control of an AC-DC converter as claimed in claim 3, wherein the phi degree is 90 degrees or 270 degrees.
5. The method for interleaving control of an AC-DC converter as claimed in claim 1, wherein the PWM signal frequency of the switching tube Q5 is N times of the PWM signal frequency of the switching tube Q1 by controlling the PWM signal frequency so that the first time is equal to the second time, and the N is an even positive number.
6. The method for interleaving control of an AC-DC converter as claimed in claim 5, wherein N is 2.
7. The alternating control device of the AC-DC converter is characterized in that the alternating control device of the AC-DC converter comprises a PFC stage and a high-frequency bridge arm of a first alternating branch circuit comprises a switching tube Q1 and a switching tube Q2, the high-frequency bridge arm of a second alternating branch circuit comprises a switching tube Q3 and a switching tube Q4, the first alternating branch circuit and the second alternating branch circuit share a power frequency bridge arm comprising a switching tube Q5 and a switching tube Q6, the switching tube Q1, the switching tube Q3 and the switching tube Q5 are upper bridge arm switching tubes, and the switching tube Q2, the switching tube Q4 and the switching tube Q6 are lower bridge arm switching tubes, and the alternating control device of the AC-DC converter comprises: a first driving signal generating module configured to control complementary conduction of the switching tube Q1 and the switching tube Q2; a second driving signal generating module configured to control complementary conduction of the switching tube Q3 and the switching tube Q4; The third driving signal generating module is configured to control the switching tube Q5 and the switching tube Q6 to be conducted complementarily by adopting a PWM modulation mode, the time for conducting the switching tube Q5 and the switching tube Q1 simultaneously is a first time, the time for conducting the switching tube Q5 and the switching tube Q3 simultaneously is a second time, and the first time is equal to the second time.
8. The interleaving control device of an AC-DC converter as claimed in claim 1, wherein the first driving signal generation module comprises: the voltage outer loop comprises an output voltage sampling circuit, a first comparator, a first PI controller, a voltage-controlled oscillator and a first fundamental wave generating circuit, wherein the voltage sampling circuit is used for obtaining a first voltage signal representing the output voltage of the AC-DC converter, the first comparator is used for comparing the first voltage signal with a first reference voltage and then outputting a first feedback signal, the first feedback signal is regulated by the first PI controller to obtain a first control quantity, the first control quantity is converted into a first variable frequency signal by the voltage-controlled oscillator, the first variable frequency signal is modulated into a first basic modulation wave signal by the first fundamental wave generating circuit, and the first basic modulation wave signal is a triangular wave signal; The current inner loop comprises a bus voltage sampling circuit, a second PI controller, an input voltage sampling circuit, a first multiplier, an inductance current sampling circuit and a third PI controller, wherein the bus voltage sampling circuit is used for acquiring a second voltage signal representing the magnitude of bus voltage, the second voltage signal is regulated by the second PI controller to obtain a second control quantity, the input voltage sampling circuit is used for acquiring phase information of the input voltage of the AC-DC converter by sampling the input voltage of the AC-DC converter, the first multiplier is used for multiplying the second control quantity by the phase information of the input voltage of the AC-DC converter to obtain a reference value signal of the inductance current inner loop, the inductance current sampling circuit is used for acquiring a second feedback signal representing the sum of inductance currents of two staggered branches, and the reference value signal and the second feedback signal of the inductance current inner loop are regulated by the third PI controller to obtain a third control quantity; And the first comparator is used for comparing the first basic modulation wave signal with the third control quantity to obtain a PWM signal of the switching tube Q1 and a PWM signal of the switching tube Q2.
9. The interleaving control device of an AC-DC converter as claimed in claim 8, wherein the second driving signal generation module comprises: the second fundamental wave generating circuit is used for carrying out inverse operation on the first basic modulation wave signal to obtain a second basic modulation wave signal; and the second comparator is used for comparing the second basic modulation wave signal with the third control quantity to obtain a PWM signal of the switching tube Q3 and a PWM signal of the switching tube Q4.
10. The interleaving control device of an AC-DC converter as claimed in claim 8, wherein the third driving signal generation module comprises: A third fundamental wave generating circuit for performing phase shift 90 ° operation or double frequency operation on the first basic modulation wave signal to obtain a third basic modulation wave signal; And the third comparator is used for comparing the third basic modulation wave signal with the third control quantity to obtain a PWM signal of the switching tube Q5 and a PWM signal of the switching tube Q6.
11. A switching power supply comprises an AC-DC converter, wherein the AC-DC converter is provided with an interleaved connection structure at a PFC stage, a high-frequency bridge arm of a first interleaved branch comprises a switching tube Q1 and a switching tube Q2, a high-frequency bridge arm of a second interleaved branch comprises a switching tube Q3 and a switching tube Q4, the first interleaved branch and the second interleaved branch share a power frequency bridge arm comprising a switching tube Q5 and a switching tube Q6, the switching tube Q1, the switching tube Q3 and the switching tube Q5 are upper bridge arm switching tubes, the switching tube Q2, the switching tube Q4 and the switching tube Q6 are lower bridge arm switching tubes, and the switching power supply is characterized by further comprising an interleaved control device of the AC-DC converter according to any one of claims 7 to 10.

Description

Alternating control method and device of AC-DC converter and switching power supply Technical Field The invention belongs to the technical field of power electronic converters, and particularly relates to an alternating control method and device of an AC-DC converter and a switching power supply. Background With the rapid development of distributed energy storage, electric automobile charging and an alternating current-direct current hybrid micro-grid, an AC-DC converter has been widely applied, and the application of a large number of power electronic devices causes serious harmonic pollution of the grid, which affects the safety of a power system. The PFC (Power factor correction) stages of the AC-DC converter can realize power factor correction, and ensure the electric energy quality of a power grid, wherein totem bridgeless PFC is widely applied due to simple structure and small loss. The staggered totem PFC technology is developed on the basis of the traditional PFC, and adopts a mode of cascading a plurality of PFC circuits, so that each PFC circuit operates in a staggered state in parallel, and input current ripple can be effectively reduced, and EMI can be reduced. The traditional AC-DC converter is a two-stage circuit, the front stage is a PFC circuit, power factor correction is realized, stable direct current voltage is provided for the rear stage, the rear stage is an isolated DC-DC circuit, voltage conversion is performed to adapt to the requirements of different input voltage occasions, but the two-stage circuit has the advantages of more adopted devices, higher cost, larger volume and complex control method. With the upgrade of power electronics technology, the requirements for AC-DC converters are further increasing, and an integrated single-stage AC-DC converter is gradually derived. The patent with publication number CN115811241B provides a PWM/PFM hybrid control method aiming at a single-stage AC-DC converter in staggered parallel connection, wherein a voltage outer loop is adopted to regulate the output voltage of the converter through PFM control, a current inner loop stabilizes bus voltage through PWM control, and the power factor of the converter is improved through nonlinear carrier control. In addition, the duty ratio of the PWM modulation is suddenly changed near the alternating current zero crossing point, so that alternating current distortion and poor power factor are caused. The simulation results are shown in fig. 2, wherein the first waveform is an output voltage waveform with the unit of V, the second waveform is an input alternating voltage waveform with the unit of V, the third waveform is an input alternating current waveform with the unit of a, the fourth waveform is an interleaved PFC inductor current waveform with the unit of a, and as can be seen from fig. 2, the control method has no engineering practicability. In order to solve the above problems, it may be tried to control the PWM modulation of the power frequency bridge arm tube near the zero crossing point to optimize the output ripple and the power factor, the simulation waveform is shown in fig. 3, the waveform is arranged from top to bottom and is identical to fig. 2, in which the continuous smooth waveform in the fourth waveform is the current waveform of the branch L b1, the waveform with abrupt change at the zero crossing point is the current waveform of the branch L b2, compared with fig. 2, the following effect of the input current is obviously improved, the output voltage ripple is effectively reduced, and the comprehensive performance of the single-stage AC-DC converter is well improved. However, for a single-stage AC-DC converter with an interleaving structure, the problem of unbalance of interleaving branches is easily caused by improper PWM modulation signal setting of a power frequency bridge arm tube, and the reliability of the single-stage AC-DC converter is seriously affected. Fig. 4 shows an expanded waveform diagram of the vicinity of the zero crossing point in fig. 3, from top to bottom, wherein the first waveform diagram is the voltage waveform of the interleaved-leg PFC inductor L b1 in V, the second waveform diagram is the voltage waveform of the interleaved-leg PFC inductor L b2 in V, the third waveform diagram is the interleaved-PFC inductor current waveform (the current waveform of the leg L b1 is the upper straight waveform, the current waveform of the leg L b2 is the lower saw tooth waveform) in a unit of a, the fourth waveform diagram is the voltage driving signal of the first interleaved-leg high-frequency bridge arm upper tube Q1 in V, the fifth waveform diagram is the voltage driving waveform of the second interleaved-leg high-frequency bridge arm upper tube Q3 in V, the sixth waveform diagram is the voltage driving waveform of the power-frequency bridge arm upper tube Q5 in V, and as apparent from fig. 4, the peak-peak of inductor current i Lb2 of one of the legs is large, while th