Power conversion system and control method thereof

Patent metadata

Field	Value
Publication number	US-2025070639-A1
Application number	US-202418619056-A
Country	US
Kind code	A1
Filing date	Mar 27, 2024
Priority date	Aug 23, 2023
Publication date	Feb 27, 2025
Grant date	—

Abstract

The disclosure discloses a power conversion system and a control method, the control method includes: providing a power conversion module which includes a damping circuit and a first capacitor connected in series, and a controller, wherein the damping circuit includes a first inductor, a first switch, a second switch, and a second capacitor; obtaining a first current reference value according to an input voltage of the power conversion module, a voltage of the second capacitor, and a voltage reference value; obtaining a second current reference value according to the input voltage of the power conversion module and a current signal related to an input current; and outputting a driving signal according to an inductor current flowing through the first inductor and an inductor current reference value, wherein the current reference value is obtained according to the first current reference value and the second current reference value.

First claim

What is claimed is:

1 . A power conversion system, comprising a power conversion module, wherein the power conversion module comprises, a damping circuit and a first capacitor connected in series, and a controller, wherein the damping circuit comprises a first inductor, a first switch, a second switch, and a second capacitor, and the first switch and the second switch are connected in series to form a first bridge arm; the first inductor is connected between an intermediate node of the first bridge arm and the first capacitor, and the second capacitor is connected in parallel to the first bridge arm, the controller comprises:
a capacitor voltage control unit, obtaining a first current reference value according to an input voltage of the power conversion module, a voltage of the second capacitor, and a voltage reference value of the second capacitor; a damping current generation unit, obtaining a second current reference value according to the input voltage of the power conversion module and a current signal related to an input current of the power conversion module; and an inductor current control unit, outputting a driving signal according to a current flowing through the first inductor and a current reference value of the first inductor to control the first switch and the second switch, in order to stabilize the input voltage of the power conversion module, wherein the current reference value of the first inductor is obtained according to the first current reference value and the second current reference value.

2 . The power conversion system according to claim 1 , wherein the capacitor voltage control unit comprises a first filter and a phase-locked loop, and the first filter and the phase-locked loop are used to track at least part of AC harmonic components of the input voltage of the power conversion module, and obtaining the first current reference value according to the at least part of the AC harmonic components, the voltage of the second capacitor and the voltage reference value of the second capacitor.

3 . The power conversion system according to claim 2 , wherein the capacitor voltage control unit further comprises a first subtracter, a first regulator, and a first multiplier, and the first subtractor performs a subtraction operation on the voltage of the second capacitor and the voltage reference value of the second capacitor to output a first error signal which is regulated by the first regulator and multiplied by a per-unit value of the at least part of AC harmonic components by the first multiplier to obtain the first current reference value.

4 . The power conversion system according to claim 2 , wherein the power conversion system further comprises a three-phase rectification circuit, and an input port of the power conversion module is connected to an output port of the three-phase rectification circuit; an input port of the three-phase rectification circuit is connected to a three-phase AC power source, and the at least part of AC harmonic components tracked by the phase-locked loop comprise a 6th harmonic component, and/or 12th harmonic component, and/or 18th harmonic component of the output voltage of the three-phase rectification circuit.

5 . The power conversion system according to claim 2 , wherein the power conversion system further comprises a single-phase rectification circuit, and an input port of the single-phase rectification circuit is connected to a single-phase AC power source; an input port of the power conversion module is connected to an output port of the single-phase rectification circuit, and the at least part of AC harmonic components tracked by the phase-locked loop comprise a second harmonic component, and/or 4th harmonic component, and/or 6th harmonic component of the output voltage of the single-phase rectification circuit.

6 . The power conversion system according to claim 1 , wherein:
the damping current generation unit comprises a second filter and a second multiplier; the second filter performs high pass filtering on the input voltage of the power conversion module to obtain a first voltage value, and the second multiplier performs a multiplication operation on the first voltage value and a first admittance parameter to obtain the second current reference value; or the damping current generation unit comprises a second filter and a first divider; the second filter performs high pass filtering on the input voltage of the power conversion module to obtain a first voltage value, and the first divider performs a division operation on the first voltage value and a first resistance parameter to obtain the second current reference value.

7 . The power conversion system according to claim 6 , wherein the damping current generation unit further comprises a third filter, a fourth filter and a second divider; the third filter performs low pass filtering on the input voltage of the power conversion module to obtain a second voltage value, and the fourth filter performs low pass filtering on a current signal related to the input current of the power conversion module to obtain a first current value;
the second divider performs a division operation on the first current value and the second voltage value to obtain a second admittance parameter, and scales the second admittance parameter based on a first coefficient to obtain the first admittance parameter; or the second divider performs a division operation on the second voltage value and the first current value to obtain a second resistance parameter, and scales the second resistance parameter based on the first coefficient to obtain the first resistance parameter.

8 . The power conversion system according to claim 7 , wherein the cutoff frequency of the second filter is 100 Hz, and the cutoff frequencies of the third filter and the fourth filter are 40 Hz; the first coefficient is 0.5.

9 . The power conversion system according to claim 1 , wherein the inductor current control unit comprises a second subtractor, a second regulator, and a first adder; the second subtractor performs a subtraction operation on the current flowing through the first inductor and the current reference value of the first inductor to output a second error signal, and the second error signal is regulated by the second regulator and added to a duty cycle feedforward value by the first adder to obtain the driving signal.

10 . The power conversion system according to claim 1 , wherein the power conversion module further comprises a second adder, and the current reference value of the first inductor is obtained by adding the first current reference value and the second current reference value through the second adder.

11 . The power conversion system according to claim 1 , wherein the power conversion system further comprises a rectification circuit and a load conversion circuit, and the input port of the power conversion module is connected in parallel to the output port of the rectification circuit and the input port of the load conversion circuit; the sum of the input current of the power conversion module and the output current of the rectification circuit is the input current of the load conversion circuit, and the load conversion circuit is a DC-AC conversion circuit or a DC-DC conversion circuit.

12 . The power conversion system according to claim 1 , wherein the damping circuit is equivalent to a resistor after being regulated by the capacitor voltage control unit, the damping current generation unit, and the inductor current control unit.

13 . The power conversion system according to claim 1 , wherein the power conversion system further comprises an AC power source, an input inductor,

Assignees

• Delta Electronics Shanghai Co

Inventors

• Xia Litao
• Bai Xinmin
• Zhang Jinfa
• Wen Bo
• Shen Zhiyu
• Barbosa Peter Mantovanelli

Classifications

• H02M1/15 Primary

  using active elements · CPC title

• H02M1/12 Primary

  Arrangements for reducing harmonics from AC input or output · CPC title

• H02M1/0048

  Circuits or arrangements for reducing losses (using snubbers H02M1/34) · CPC title

• H02M1/088

  for the simultaneous control of series or parallel connected semiconductor devices · CPC title

• H02M3/158

  including plural semiconductor devices as final control devices for a single load · CPC title