US-12627235-B2 - Forward converter and forward power factor corrector

US12627235B2US 12627235 B2US12627235 B2US 12627235B2US-12627235-B2

Abstract

A forward converter includes a voltage conversion device, a switch and an auxiliary device. The voltage conversion device includes a primary winding and a secondary winding, and is configured to convert an input voltage into an output voltage. The switch is connected to the voltage conversion device, and is switched to make the voltage conversion device receive or not receive the input voltage. The auxiliary device is connected to the voltage conversion device. When the switch is cut off, the auxiliary device stores electrical energy released by the voltage conversion device and generates a compensation voltage, and when the switch is turned on, the auxiliary device provides the compensation voltage, wherein the compensation voltage and the input voltage have same polarity. The present disclosure further provides a forward power factor corrector including the forward converter described above and a rectifying device.

Inventors

Wen-Tien Tsai
Ching-Ran Lee
Le-Ren CHANG-CHIEN
Chun-Wei Lin

Assignees

INDUSTRIAL TECHNOLOGY RESEARCH INSTITUTE

Dates

Publication Date: 20260512
Application Date: 20240118
Priority Date: 20230927

Claims (10)

1 . A forward converter, comprising: a voltage conversion device comprising a primary winding and a secondary winding and configured to convert an input voltage into an output voltage; a switch connected to the voltage conversion device and configured to be switched to make the voltage conversion device receive or not receive the input voltage; and an auxiliary device connected to the voltage conversion device, storing electrical energy released by the voltage conversion device and generating a compensation voltage when the switch is cut off, and providing the compensation voltage when the switch is turned on, wherein the compensation voltage and the input voltage have same polarity, wherein the auxiliary device comprises: an auxiliary capacitor; an auxiliary diode, wherein an anode of the auxiliary diode is connected to a first terminal of the auxiliary capacitor; and an auxiliary winding inductively coupled to the primary winding and the secondary winding, wherein a terminal of the auxiliary winding is connected to a cathode of the auxiliary diode, and another terminal of the auxiliary winding is connected to a second terminal of the auxiliary capacitor.
2 . The forward converter according to claim 1 , wherein the voltage conversion device further comprises an energy storage inductor configured to output the output voltage, the auxiliary diode is a first auxiliary diode, the auxiliary winding is a first auxiliary winding, and the auxiliary device further comprises: a second auxiliary diode, wherein an anode of the second auxiliary diode is connected to the first terminal of the auxiliary capacitor; and a second auxiliary winding inductively coupled to the energy storage inductor, wherein a terminal of the second auxiliary winding is connected to a cathode of the second auxiliary diode, and another terminal of the second auxiliary winding is connected to the second terminal of the auxiliary capacitor.
3 . The forward converter according to claim 1 , wherein the voltage conversion device further comprises an energy storage inductor configured to output the output voltage.
4 . The forward converter according to claim 1 , wherein the voltage conversion device further comprises an energy storage inductor, a first terminal of the energy storage inductor configured to output the output voltage, a terminal of the auxiliary device is connected to the secondary winding, and another terminal of the auxiliary device is connected to a second terminal of the energy storage inductor.
5 . The forward converter according to claim 4 wherein the first terminal of the auxiliary capacitor is connected to the secondary winding, the second terminal of the auxiliary capacitor is connected to the second terminal of the energy storage inductor.
6 . The forward converter according to claim 1 , wherein the auxiliary diode is a first auxiliary diode, the auxiliary winding is a first auxiliary winding, and the auxiliary device further comprises: a second auxiliary diode, wherein an anode of the second auxiliary diode is connected to the first terminal of the auxiliary capacitor; and a second auxiliary winding inductively coupled to the energy storage inductor, wherein a terminal of the second auxiliary winding is connected to a cathode of the second auxiliary diode, and another terminal of the second auxiliary winding is connected to the second terminal of the auxiliary capacitor.
7 . The forward converter according to claim 1 , wherein a terminal of the auxiliary device is configured to receive the input voltage, and another terminal of the auxiliary device is connected to the primary winding.
8 . The forward converter according to claim 7 wherein the first terminal of the auxiliary capacitor is configured to receive the input voltage, and the second terminal of the auxiliary capacitor is connected to the primary winding.
9 . The forward converter according to claim 8 , wherein the voltage conversion device further comprises an energy storage inductor configured to output the output voltage, the auxiliary diode is a first auxiliary diode, the auxiliary winding is a first auxiliary winding, and the auxiliary device further comprises: a second auxiliary diode, wherein an anode of the second auxiliary diode is connected to the first terminal of the auxiliary capacitor; and a second auxiliary winding inductively coupled to the energy storage inductor, wherein a terminal of the second auxiliary winding is connected to a cathode of the second auxiliary diode, and another terminal of the second auxiliary winding is connected to the second terminal of the auxiliary capacitor.
10 . A forward power factor corrector, comprising: the forward converter according to claim 1 ; and a rectifying device connected to the forward converter and configured to receive and rectify a power source to generate the input voltage.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This non-provisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No(s). 63/525,139 filed in U.S. on Jul. 5, 2023 and Patent Application No(s). 112137010 filed in Republic of China (ROC) on Sep. 27, 2023, the entire contents of which are hereby incorporated by reference. BACKGROUND 1. Technical Field This disclosure relates to a forward converter and forward power factor corrector. 2. Related Art At present, many electrical appliances use low-voltage direct current. However, since power provided by the supply mains is alternating current (AC), alternating current-direct current conversion is required. In order to reduce the reactive power of the power system and reduce the system interference caused by current harmonics, many electrical appliances are required to have high power factor and low current harmonics, so power factor correctors are widely used. Based on safety and performance considerations, power factor correctors are required to have high power factor, high conversion efficiency and electrical isolation. Conventional circuit structures such as fly-back structure have poor conversion efficiency; and for conventional forward circuits, when the input AC power is in a low voltage state, if the induced voltage on the secondary side is less than the output voltage of the power factor corrector, the input current cannot be introduced, resulting in a current dead zone. Therefore, the power factor correction effect is compromised, and additional transformer is needed to deal with demagnetization requirement. Other conventional technologies and circuit structures also face different technical bottlenecks and cannot meet increasingly stringent regulatory requirements. SUMMARY According to one or more embodiment of this disclosure, a forward converter includes a voltage conversion device, a switch and an auxiliary device. The voltage conversion device includes a primary winding and a secondary winding and is configured to convert an input voltage into an output voltage. The switch is connected to the voltage conversion device and is configured to be switched to make the voltage conversion device receive or not receive the input voltage. The auxiliary device is connected to the voltage conversion device, stores electrical energy released by the voltage conversion device and generating a compensation voltage when the switch is cut off, and providing the compensation voltage when the switch is turned on, wherein the compensation voltage and the input voltage have same polarity. According to one or more embodiment of this disclosure, a forward power factor corrector includes the forward converter described above and a rectifying device connected to the forward converter and configured to receive and rectify a power source to generate the input voltage. BRIEF DESCRIPTION OF THE DRAWINGS The present disclosure will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only and thus are not limitative of the present disclosure and wherein: FIG. 1 is a block diagram illustrating a forward converter according to an embodiment of the present disclosure; FIG. 2 is a block diagram illustrating a forward power factor corrector according to an embodiment of the present disclosure; FIG. 3 is a block diagram illustrating a forward power factor corrector according to another embodiment of the present disclosure; FIG. 4 exemplarily illustrates a circuit diagram of a rectifying device and a filtering device included in forward power factor of FIG. 3; FIG. 5 is a circuit diagram of illustrating the forward converter according to a first embodiment of the present disclosure; FIG. 6A to FIG. 6C illustrate a first operation mode, a second operation mode and a third operation mode of the forward converter of FIG. 5, respectively; FIG. 7 is a circuit diagram of illustrating the forward converter according to a second embodiment of the present disclosure; FIG. 8A to FIG. 8D illustrate a first operation mode, a second operation mode, a third operation mode and a fourth operation mode of the forward converter of FIG. 7, respectively; FIG. 9 is a circuit diagram of illustrating the forward converter according to a third embodiment of the present disclosure; FIG. 10A to FIG. 10C illustrate a first operation mode, a second operation mode and a third operation mode of the forward converter of FIG. 9, respectively; FIG. 11 is a circuit diagram of illustrating the forward converter according to a fourth embodiment of the present disclosure; FIG. 12A to FIG. 12D illustrate a first operation mode, a second operation mode, a third operation mode and a fourth operation mode of the forward converter of FIG. 11, respectively; FIG. 13 is a circuit diagram of illustrating the forward converter according to a fifth embodiment of the present disclosure; FIG. 14A to FIG. 14C illustrate a fir