CN-115864816-B - Sepic type power correction circuit based on switching inductance

CN115864816BCN 115864816 BCN115864816 BCN 115864816BCN-115864816-B

Abstract

The Sepic type power correction circuit based on the switching inductance comprises a switching tube S 1 ~S 3 , a diode D 1 ~D 5 , an inductance L 1 ~L 5 , a capacitor C 1 and a capacitor C o . The diode D 3 ~D 5 and the inductor L 4 、L 5 form a switched inductor structure. Compared with the traditional Sepic PFC converter, the Sepic type power correction circuit based on the switching inductance improves the voltage reduction gain, ensures that the whole duty ratio range is in a voltage reduction state, has larger duty ratio under the condition of high voltage reduction ratio than the traditional Sepic PFC converter, and effectively avoids the occurrence of the limit duty ratio condition. By adopting the bridgeless structure, lower conduction loss can be realized. The original output diode is replaced by a switch inductance structure, so that output current is continuous, and filtering of the output current is facilitated. And all the switching tubes are commonly grounded, so that a lower-cost driving circuit can be adopted.

Inventors

LI WENJING
YAO JUNWEI
XIE QIONGYAO
HE QI
FAN LIPING
MA HUI

Assignees

三峡大学

Dates

Publication Date: 20260508
Application Date: 20221107

Claims (4)

1. The Sepic type power correction circuit based on the switching inductance comprises an alternating current power supply u s , a switching tube S 1 ~S 3 , a diode D 1 ~D 5 , an inductance L 1 ~L 5 and a capacitance C 1 、C o , and is characterized in that: One side of an alternating current power supply u s is respectively connected with the drain electrode of the switching tube S 3 and one end of an inductor L 1 , and the other end of the inductor L 1 is connected with the anode of a diode D 1 ; The other side of the alternating current power supply u s is respectively connected with the drain electrode of the switching tube S 2 and one end of the inductor L 2 , and the other end of the inductor L 2 is connected with the anode of the diode D 2 ; The anode of the capacitor C 1 is connected with the cathode of the diode D 1 , the cathode of the diode D 2 and the drain of the switching tube S 1 respectively; One end of the inductor L 3 is respectively connected with the cathode of the capacitor C 1 , the anode of the diode D 3 and one end of the inductor L 4 , and the other end of the inductor L 3 is respectively connected with the source electrode of the switching tube S 1 , the source electrode of the switching tube S 2 , the source electrode of the switching tube S 3 and the cathode of the output capacitor C o ; the other end of the inductor L 4 is respectively connected with the anode of the diode D 4 and the anode of the diode D 5 ; The cathode of the diode D 5 is respectively connected with the cathode of the diode D 3 and one end of the inductor L 5 ; The other end of the inductor L 5 is respectively connected with the cathode of the diode D 4 and the anode of the output capacitor C o ; The output capacitor C o is connected with the load R L in parallel; The power correction circuit has the following four working modes: The first working mode is that the circuit works in a positive half period of an alternating current power supply u s , a switching tube S 1 and a switching tube S 2 are switched on, a switching tube S 3 is switched off, a diode D 1 、D 5 is positively biased on, and other diodes are reversely cut off, the alternating current power supply u s charges an inductor L 1 , a capacitor C 1 discharges to charge an inductor L 3 , the current of the inductor L 1 、L 3 linearly rises, the inductors L 4 and L 5 discharge to an output capacitor C o and a load through a diode D 5 , and the currents of the inductors L 4 and L 5 linearly fall; The second working mode is that the circuit works in the positive half period of the alternating current power supply u s , the switching tube S 2 is switched on, the switching tube S 1 、S 3 is switched off, the diode D 1 、D 3 、D 4 is positively biased on, and the other diodes are reversely switched off, the process capacitor C 1 is charged, and the inductor L 1 、L 3 discharges to the inductor L 4 、L 5 , the load and the output capacitor C o ; The third working mode is that the circuit works in a negative half period of an alternating current power supply u s , a switching tube S 1 and a switching tube S 3 are switched on, a switching tube S 2 is switched off, a diode D 2 、D 5 is positively biased on, and other diodes are reversely cut off, the alternating current power supply u s charges an inductor L 2 , a capacitor C 1 discharges to charge an inductor L 3 , the current of the inductor L 2 、L 3 linearly rises, the inductors L 4 and L 5 discharge to an output capacitor C o and a load through a diode D 5 , and the currents of the inductors L 4 and L 5 linearly fall; The circuit works in a negative half period of an alternating current power supply u s , a switching tube S 3 is switched on, a switching tube S 1 、S 2 is switched off, a diode D 2 、D 3 、D 4 is positively biased on, other diodes are reversely switched off, a process capacitor C 1 is charged, and an inductor L 2 、L 3 discharges to an inductor L 4 、L 5 , a load and an output capacitor C o .
2. The Sepic type power correction circuit based on switching inductance according to claim 1, wherein the switching inductance unit is composed of an inductance L 4 , an inductance L 5 , a diode D 3 , a diode D 4 and a diode D 5 .
3. The method of claim 1, wherein the switching transistors S 1 , S 2 , S 3 are grounded, and the power switching transistors S 1 , S 2 , S 3 are insulated gate bipolar transistor IGBT, integrated gate commutated thyristor IGCT, or power field effect transistor MOSFET.
4. The Sepic-type power correction circuit based on switching inductance of claim 1, wherein the voltage gain of the power correction circuit is D/(2-D).

Description

Sepic type power correction circuit based on switching inductance Technical Field The invention relates to the technical field of power electronic converters, in particular to a Sepic type power correction circuit based on a switching inductance. Background The traditional Buck PFC converter has wide application, and the power factor is not high because of discontinuous input current and current dead zone. However, according to the standard of IEC61000-3-2, when the rated power of the D-class electric appliance connected to the power grid is more than 75W, certain harmonic current inhibition requirements must be met, otherwise harmonic pollution is brought to the power grid. The application of Buck PFC converters is limited. The traditional Sepic PFC converter can easily realize the buck-boost function, and is suitable for a wide input voltage range. Is one of the topologies widely used in medium and small power classes. The input end of the Sepic PFC circuit is provided with an inductor, and the input current is continuous, so that the power factor of the converter is improved and THD is reduced. However, to achieve a high buck conversion ratio requires the switching tube to operate at a very low duty cycle, which can lead to converter instability and low conversion efficiency. Therefore, it is necessary to design a circuit capable of solving the above-described problems. Disclosure of Invention The invention provides a Sepic type power correction circuit based on a switching inductance, which aims to solve the problems that the efficiency of the conventional Sepic PFC converter is low, the duty ratio range is only 0-0.5 in a buck mode, and the duty ratio of a switching tube is extremely low under the condition of high buck ratio. The output diode in the original Sepic PFC converter is replaced by a switching inductance unit comprising 5 elements. Compared with the traditional Sepic PFC converter, the power correction circuit improves the buck gain, ensures that the buck state is maintained in the full duty ratio range, has larger duty ratio than the traditional Sepic PFC converter under the condition of high buck ratio, and effectively avoids the occurrence of the limit duty ratio condition. The technical scheme adopted by the invention is as follows: The Sepic type power correction circuit based on the switching inductance comprises an alternating current power supply u s, a switching tube S 1～S3, a diode D 1～D5, an inductance L 1～L5, a capacitance C 1、Co, One side of an alternating current power supply u s is respectively connected with the drain electrode of the switching tube S 3 and one end of an inductor L 1, and the other end of the inductor L 1 is connected with the anode of a diode D 1; The other side of the alternating current power supply u s is respectively connected with the drain electrode of the switching tube S 2 and one end of the inductor L 2, and the other end of the inductor L 2 is connected with the anode of the diode D 2; The anode of the capacitor C 1 is connected with the cathode of the diode D 1, the cathode of the diode D 2 and the drain of the switching tube S 1 respectively; One end of the inductor L 3 is respectively connected with the cathode of the capacitor C 1, the anode of the diode D 3 and one end of the inductor L 4, and the other end of the inductor L 3 is respectively connected with the source electrode of the switching tube S 1, the source electrode of the switching tube S 2, the source electrode of the switching tube S 3 and the cathode of the output capacitor C o; the other end of the inductor L 4 is respectively connected with the anode of the diode D 4 and the anode of the diode D 5; The cathode of the diode D 5 is respectively connected with the cathode of the diode D 3 and one end of the inductor L 5; The other end of the inductor L 5 is respectively connected with the cathode of the diode D 4 and the anode of the output capacitor C o; The output capacitor C o is connected in parallel with the load R L. In the power correction circuit, an inductor L 4, an inductor L 5, a diode D 3, a diode D 4, and a diode D 5 constitute a switching inductance unit. In the power correction circuit, the switching tube S 1, the switching tube S 2 and the switching tube S 3 are grounded, and the power switching tube S 1, the switching tube S 2 and the switching tube S 3 are insulated gate bipolar transistor IGBTs, integrated gate commutated thyristors IGCTs or power field effect transistors MOSFETs. The voltage gain of the power correction circuit is D/(2-D). The power correction circuit has the following four working modes in CCM mode: In the first working mode, the circuit works in the positive half cycle of the alternating current power supply u s, the switching tubes S 1 and S 2 are turned on, and the switching tube S 3 is turned off. Diode D 1、D5 is forward biased on and the remaining diodes are reverse off. In the process, the alternating current power supply u s charges the