WO2022188853A1

WO2022188853A1 - Half-wave symmetric converter and control method

Info

Publication number: WO2022188853A1
Application number: PCT/CN2022/080291
Authority: WO
Inventors: 严宗周
Original assignee: 深圳原能电器有限公司
Priority date: 2021-03-12
Filing date: 2022-03-11
Publication date: 2022-09-15
Also published as: CN113162439A

Abstract

Disclosed in the present invention are a half-wave symmetric converter and a control method. The half-wave symmetric converter is composed of a first half-wave rectifying circuit and a second half-wave rectifying circuit. Each of the half-wave rectifying circuits is composed of any one of a diode and a switch tube, or a combination of the two. The two half-wave rectifying circuits are electrically connected to an input end of an alternating-current bus bar, and are respectively connected to sine waves of an upper half cycle and a lower half cycle for rectification, and rectified currents are then output. According to requirements, a control circuit, a potential energy conversion unit, a booster circuit, etc., may also be added to further improve the functions, and a single-stage PFC converter can be formed by adding a PFC unit. The control method for the half-wave symmetric converter itself and a control method with the PFC unit added comprise: dividing a sine wave of a single cycle into a plurality of nodes, dividing stages according to the nodes, and then controlling the energy output and distribution in each stage. By means of the present invention, a mains power supply is effectively rectified, the overall power consumption and volume are reduced, and a stable and reliable output is provided by adding a PFC unit.

Description

A half-wave symmetric converter and its control method

technical field

The invention relates to the technical field of converters, in particular to a half-wave symmetrical converter and a control method.

Background technique

The existing high-power power supply requires a large current, and the normal structure needs to be rectified first and then multi-channel or single-channel output. During rectification, the existing converter generally requires two tubes to be connected in series, resulting in a relatively high power consumption for rectification. Large; such as a 100W power supply, only the rectifier bridge needs about 1.8W of power at low voltage input.

For existing converters or buck-boost circuits, in order to effectively utilize the power grid, many products require high power factors, such as LED lamp power supplies and power supplies above 75W. In order to achieve high PF, two-pole conversion is usually required. For buck or boost conversion, the two conversions require two inductors or one inductor plus a transformer, and this design not only wastes part of the energy but also increases the overall volume. In the conventional single-stage PFC in the market, since the current and voltage are in the same phase, according to P=U*I, the output current has a large power frequency fluctuation; the other way is the valley-filling, flicker-free single-stage PFC converter, but The PFC capacitor set behind the bridge stack of this kind of converter is not easy to choose in terms of energy storage time and energy storage size, and it is difficult to control effectively, and the PFC capacitor starts to be charged in the boost stage until The peak value is cut off at 90 degrees, so the PF value cannot be made very high, the actual use effect is relatively poor, and the service life is not long; another is to connect the rectifier to the winding and connect a capacitor to store energy. This structure, due to this scheme Unable to control the charging time of the energy storage capacitor, it also causes the current to store a lot of energy in the rising stage. After reaching the peak value of 90 degrees, it cannot store energy, resulting in serious deformation of the current, unable to achieve a high PF value, and the capacitor voltage can only be equal to the input voltage plus Winding voltage, resulting in high voltage and short life.

Therefore, there is an urgent need for a half-wave symmetric converter and a control method that can solve one or more of the above problems.

SUMMARY OF THE INVENTION

In order to solve one or more problems existing in the prior art, the present invention provides a half-wave symmetric converter and a control method. The technical solution adopted by the present invention to solve the above problems is: a half-wave symmetric converter, comprising: a first half-wave rectifier circuit, a second half-wave rectifier circuit, the first half-wave rectifier circuit and the second half-wave rectifier circuit The half-wave rectifier circuit is composed of any one or both of diodes and switch tubes;

The first half-wave rectifier circuit and the second half-wave rectifier circuit are connected in parallel at the AC input end, and a sine wave cycle of the AC input end is divided into a positive half cycle and a negative half cycle, and one half cycle is connected to the first half-wave rectifier In the circuit, the other half cycle of the AC input terminal is connected to the second half-wave rectifier circuit;

The other end of the two-way half-wave rectification circuit is electrically connected to the load or the converter, so as to form a complete input waveform for the alternating current, eliminating the need for primary rectification.

Further, including: a control circuit and a potential energy conversion unit,

The control circuit is composed of switch tubes and/or diodes;

The potential energy conversion unit is an inductor or a transformer, and the potential energy conversion unit is provided with two groups;

The control circuit controls the connection of the first half-wave circuit and the potential energy conversion unit to form a first loop; the control circuit controls the connection of the second half-wave circuit and another potential energy conversion unit to form a second loop. Symmetrically form a half-wave symmetric converter;

The first loop and the second loop are set as any one of a boost circuit, a buck circuit, a boost circuit, a forward excitation circuit and a flyback circuit as required;

The two outputs of the first loop and the second loop are combined into one output circuit as required.

Further, the first half-wave rectifier circuit and the second half-wave rectifier circuit are commutated and electrically connected to different input end windings of the same magnetic core transformer, and alternate the first half cycle and the second half cycle on the corresponding voltage waveform of the input voltage. For two half cycles, the secondary forms the output voltage of the same phase.

Further, it also includes: a PFC unit, the PFC unit is provided with an energy storage capacitor and at least one switch tube, and the position where the PFC unit is placed includes one or a combination of the following three types:

Method 1, electrically connecting to the first half-wave rectifier circuit and/or the second half-wave rectifier circuit;

Method 2, electrically connecting between the windings of the first half-wave rectifier circuit and the second half-wave rectifier circuit;

The third method is to electrically connect between the winding and the ground.

And a control method for a half-wave symmetric converter, dividing the following nodes with 0 to 360 degrees of the rectified sine wave as a cycle period:

T0, T0 is the lowest valley point of the voltage;

T1 and T1 are set in the voltage rising stage, the voltage at T1 is greater than that at T0, which is the low voltage boost point in the positive half cycle;

T2, T2 are set in the voltage rising stage, the voltage at T2 is greater than that at T1, which is the positive half-cycle boost high voltage point;

T3 and T3 are high voltage points in the positive half cycle, and the voltage at T3 is greater than that at T2;

T4, T4 are set in the voltage drop stage, the voltage at T4 is less than the voltage at T3, which is the high-voltage point of the positive half-cycle step-down;

T5, T5 are set in the voltage drop stage, the voltage at T5 is less than the voltage at T4, which is the low voltage drop point in the positive half cycle;

T1A and T1A are set in the voltage rising stage, the voltage at T1A is greater than that at T0A, which is the low voltage boost point in the negative half cycle;

T2A, T2A are set in the voltage rising stage, the voltage at T2A is greater than that at T1A, which is the negative half-cycle boost high voltage point;

T3A, T3A is the negative half cycle high voltage point, the voltage at T3A is greater than that at T2A;

T4A, T4A are set in the voltage drop stage, the voltage at T4A is less than the voltage at T3A, which is the negative half-cycle step-down high-voltage point;

T5A, T5A are set in the voltage drop stage, the voltage at T5A is less than the voltage at T4A, which is the low voltage step-down point in the negative half cycle;

Depending on the location of the PFC unit, the PFC unit is charged in the boost or high voltage stage;

In the trough stage: any one or more stages of the T4-T2 stage, the T4A-T2A stage, the T5-T1 stage, and the T5A-T1A stage, the PFC unit releases electric energy to fill the valley.

Further, when the PFC unit is arranged on the input bus, in the boost stage of T0-T3, T0-T3A, T1-T3, T1A-T3A, T2-T3, T2A-T3A, or T2-T4, T2A- During one of the T4A high voltage phases, the second loop is either permanently on or intermittently on to charge the PFC cell.

Further, when the PFC unit is arranged between the winding and the ground, at the peak time of the input sine wave, that is, in the T2-T4 and T2A-T4A stages, the PFC unit is stored and charged as follows:

When the voltage of the PFC unit is lower than the input voltage, the control unit controls the input to distribute energy to the PFC unit and the potential energy change unit as required;

In the voltage rising stage, the proportion of the energy input to the PFC unit is gradually increased, that is, the on-time of the PFC unit is increased;

In the voltage drop stage, the proportion of the energy input to the PFC unit is gradually reduced, that is, the on-time of the PFC unit is reduced;

The proportion of energy distribution is controlled by controlling the on-time of the PFC cell.

Further, in the stages T2-T4 and T2A-T4A, when the voltage of the PFC unit is higher than the input voltage, the first loop or the second loop is turned on first, and the input energy is stored in the potential energy conversion unit. Among them, after closing the first loop or the second loop, the current of the potential energy conversion unit changes from increasing to decreasing, and the winding forms a back pressure, which is then adjusted by any of the following methods:

Mode 1: Turn on the PFC unit, store the entire switching cycle in the PFC unit or directly transfer it to the secondary, and take one cycle or repeat more than one cycle to process in mode 1;

Method 2: Distribute the energy stored in the potential energy conversion unit for a single time to the PFC unit and output in turn;

The above distribution current increases as the input voltage increases, the storage ratio of the PFC unit increases, and as the input voltage decreases, the storage ratio to the PFC unit decreases.

Further, at a low time, that is, a stage in T5-T1, and T5A-T1A and/or T4-T2, T4A-T2A stage, the connection of the PFC unit and the input is any of parallel, series and series-parallel combination. One, combine the input to the potential energy transformation unit to fill the valley and output, and pass it to the output through the potential energy transformation unit.

Further, add ACF modules and multiple output modules as needed.

The beneficial effect of the present invention is that, by arranging the first half-wave rectifier circuit, the second half-wave rectifier circuit, the control circuit and the potential energy conversion unit in the converter, the present invention realizes that only one rectifier tube or The synchronous tube can obtain the rectified waveform, and through the commutation access of two different windings, the isolated output can be realized by one transformer; according to the needs, a PFC unit can also be set to make a single-stage PFC converter. In order to reduce unnecessary power, improve energy conversion efficiency and reduce the overall volume; and the coordinated control method is: divide a single cycle of the mains into multiple nodes, integrate the nodes into multiple time periods, and control the circuit according to the time. It controls the work of other units and components, realizes the process of adjusting rectification, input and input, and adjusts the energy with the PFC unit, so that when the PF value is high, the excess energy during the peak period is stored in the PFC unit. The energy stored in the PFC unit is released as needed, thereby improving the PF value and stabilizing the output; with the boost and boost circuit and the control circuit, the PFC capacitor in the PFC unit can be controlled at a lower voltage to reduce the PFC capacitor. Withstand voltage, thereby improving the service life; some common components or circuits are subtracted from the design, and the conversion of primary energy is reduced, circuit loss is reduced, and the overall volume of the converter is reduced. The above greatly improves the practical value of the present invention.

Description of drawings

1 is a schematic diagram of a half-wave symmetrical module of a half-wave symmetrical converter of the present invention;

Fig. 2 is a schematic diagram of the half-wave symmetry of a half-wave symmetric converter of the present invention and a buck-boost output at the same time;

3 is a schematic diagram of a half-wave symmetrical two-way isolated output of a half-wave symmetrical converter of the present invention;

4 is a schematic diagram of a half-wave symmetrical non-isolated single output of a half-wave symmetrical converter of the present invention;

5 is a schematic diagram of a half-wave symmetrical step-down unipolar converter of a half-wave symmetrical converter of the present invention;

6 is a schematic diagram of a half-wave symmetrical commutation combination of a half-wave symmetrical converter of the present invention;

7 is a half-wave symmetrical converter architecture of a half-wave symmetrical converter of the present invention;

8 is a schematic diagram of a half-wave symmetrical unipolar PFC converter of a half-wave symmetrical converter of the present invention;

9 is a schematic diagram of a simplified half-wave symmetrical single-stage PFC converter of a half-wave symmetrical converter of the present invention;

10 is a schematic diagram of a single-stage PFC, half-wave symmetry, and multiple outputs of a half-wave symmetric converter of the present invention;

11 is a schematic diagram of a half-wave symmetrical forward converter of a half-wave symmetrical converter of the present invention;

12 is a half-wave symmetrical conduction waveform diagram of a half-wave symmetrical converter of the present invention;

13 is a waveform diagram of the half-wave symmetrical whole cycle distribution and parallel valley filling of a half-wave symmetrical converter of the present invention;

14 is a waveform diagram of a half-wave symmetrical energy storage series filling valley of a half-wave symmetrical converter of the present invention;

15 is a waveform diagram of valley filling of a half-wave symmetrical single-stage PFC series-parallel combination of a half-wave symmetrical converter of the present invention.

Detailed ways

In order to make the above objects, features and advantages of the present invention easier to understand, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, the present invention can be implemented in many other ways different from this description, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

As shown in FIGS. 1-11 , the present invention discloses a half-wave symmetric converter, and a unipolar PFC converter made by combining PFC units using the half-wave symmetric converter.

A half-wave symmetric converter, comprising: a first half-wave rectifier circuit and a second half-wave rectifier circuit, wherein the first half-wave rectifier circuit and the second half-wave rectifier circuit are composed of any one of a diode and a switch tube. one or two compositions,

As shown in Figure 1, the first half-wave rectifier circuit is composed of an AC bus input terminal, a diode D1, and a load 1, and the second half-wave rectifier circuit is composed of an AC bus input terminal, a diode D1A, and a load 1A, wherein the load 1. The load 1A can be a secondary circuit, such as a booster circuit, a buck circuit, a buck-boost circuit, a transformer, etc., or a normal load.

Specifically, as shown in FIG. 2, it also includes: a control circuit and a potential energy conversion unit,

The control circuit is composed of switch tubes and/or diodes;

It should be noted that, as shown in FIG. 2 , the control circuit is a switch tube K1 and a switch tube K1A, and the potential energy conversion unit is an inductance LP and an inductance LPA; wherein the first loop is: the AC bus input end, Diode D1, switch tube K1 and inductor LP, the second loop is: AC bus input terminal, switch tube K1A, inductor LPA and diode D1A. A buck-boost circuit is formed by adding a diode D7 and a capacitor EC3 to the first loop, and a buck-boost circuit is formed by adding a diode D7A and a capacitor EC3A to the second loop to meet requirements. As shown in FIG. 11 , the first loop and the second loop can also be electrically connected to different windings at the input end of the transformer to form a forward circuit.

Specifically, the first half-wave rectifier circuit and the second half-wave rectifier circuit are commutated and electrically connected to different input windings of the same magnetic core transformer, and alternate the first half cycle and the second half cycle on the corresponding voltage waveform of the input voltage. For two half cycles, the secondary forms the output voltage of the same phase.

As shown in FIG. 3 , the first loop is connected to the input end of the transformer T1, and the second loop is connected to the input end of the transformer T1A, and the transformer T1 and the transformer T1A form two outputs. As shown in FIG. 6 , the first loop and the second loop are commutated and electrically connected to different windings at the input end of the transformer T1 to form a commutated and combined isolated single-channel output. As shown in FIG. 4 , the first loop and the second loop are commutated and connected to the capacitor EC3 to form a non-isolated single output.

Specifically, it also includes: a PFC unit, the PFC unit is provided with an energy storage capacitor and at least one switch tube, and the position where the PFC unit is placed includes one or a combination of the following three types:

The third method is to electrically connect between the winding and the ground.

As shown in FIG. 5 , the PFC unit is composed of a capacitor EC1P, a switch tube K21 and a switch tube K12, and is electrically connected to the second half-wave rectifier circuit, and a step-down circuit is added to the two half-wave rectifier circuits. , forming a half-wave symmetrical buck unipolar converter.

FIG. 7 is a schematic diagram of a further modification on the half-wave symmetrical commutation combining circuit shown in FIG. 6 , which constitutes a single output architecture of a half-wave symmetrical single-stage PFC converter. 8 and 9 are schematic diagrams of adding the PFC unit to the half-wave symmetrical commutation combining circuit shown in FIG. 6 . The PFC unit is electrically connected to the second half-wave rectifier circuit to form a half-wave symmetrical unit Schematic diagram of a stage PFC converter. Fig. 10 is a schematic diagram of a single-stage PFC, half-wave symmetric transformation, and multiple output functions based on Fig. 6-Fig. 9. The PFC unit is electrically connected to the second half-wave rectifier circuit, And it is commutated and combined through a transformer T1, and a multi-channel output circuit is set on the output winding of the transformer T1.

2 and 3 combined with the half-wave symmetrical conduction waveform diagram shown in FIG. 12, it can be seen that the working process and state of the internal diode and switch tube of the present invention when in use, the first half-wave rectifier circuit and the second half-wave rectifier circuit. The wave rectification circuit rectifies the sine waves of the upper half cycle and the lower half cycle respectively, and outputs them.

T0, T0 is the lowest valley point of the voltage;

FIG. 13 is a waveform diagram of energy distribution for the PFC unit and the output end and valley filling at low voltage in the whole cycle of half-wave symmetry. Fig. 13 is combined with Fig. 8, the switch tube KP is the control switch tube inside the PFC unit, the light shaded portion in Fig. 13 corresponds to the charging of the energy storage capacitor in the PFC unit, and the dark shaded portion corresponds to the PFC unit Carry out valley filling release. The switch tube K1 and the switch tube K1A control the circuit to boost or step down, and the switch tube KP12 and the switch tube KP21 control the energy of the first half-wave rectifier circuit and the second half-wave rectifier circuit to the PFC unit and the output terminal. Allocation, in the valley filling and releasing process, the PFC unit is connected in parallel with the first half-wave rectifier circuit or the second half-wave rectifier circuit. 14 is a waveform diagram of valley filling of the PFC unit in series with the first half-wave rectifier circuit or the second half-wave rectifier circuit, wherein the IAC at the bottom is a waveform diagram of the output current.

Combined with the waveform diagrams shown in Figure 13-Figure 15, when the PFC unit is set on the input bus, the voltage is boosted at T0-T3, T0-T3A, T1-T3, T1A-T3A, T2-T3, T2A-T3A phase, or one of the high voltage phases T2-T4, T2A-T4A, the second loop is either permanently on or intermittently on to charge the PFC unit.

It should be pointed out that, as shown in FIG. 9 and FIG. 14 , when the PFC unit is set between the winding and the ground, at the peak time of the input sine wave, that is, in the stages T2-T4 and T2A-T4A, the PFC unit is The way to charge the energy storage is as follows:

Specifically, in the stages T2-T4 and T2A-T4A, when the voltage of the PFC unit is higher than the input voltage, the first loop or the second loop is turned on first, and the input energy is stored in the potential energy conversion unit Among them, after closing the first loop or the second loop, the current of the potential energy conversion unit changes from increasing to decreasing, and the winding forms a back pressure, which is then adjusted by any of the following methods:

Mode 2: Distribute the energy stored in the potential energy conversion unit for a single time to the PFC unit and output in turn;

It should be pointed out that, at the time of the trough, that is, one stage in the T5-T1, and T5A-T1A and/or T4-T2, T4A-T2A stages, the connection between the PFC unit and the input is in parallel, series, and series-parallel combination. Any one of , and then combine the input to the potential energy transformation unit to fill the valley and output, and pass it to the output through the potential energy transformation unit. Refer to the waveform diagram of the half-wave symmetric PFC series-parallel combination valley filling described in FIG. 15 .

It should be noted that ACF modules and multi-output modules can be added as needed. In the schematic layout, each device can be placed in different positions, such as D7, DP, LP, T1, K1, KP, KP1, KP2, etc. can be placed on the positive side It can also be at the negative end, or combined differently; further diodes can be changed to switch tubes to reduce losses as needed; further switch tubes can be one or more combinations of MOS tubes, triodes, thyristors, gallium nitride, etc. . Different EMC components and safety components can be added as needed, diodes, transistors, resistors, capacitors, optocouplers and other elements can be added as needed; further switches, VCC startup circuits, voltage divider detection circuits, current limit detection circuits, etc. can be externally installed , can also be integrated into the chip or composite.

To sum up, the present invention realizes that only one rectifier tube or synchronous tube is used in a half rectification cycle by arranging the first half-wave rectifier circuit, the second half-wave rectifier circuit, the control circuit and the potential energy conversion unit in the converter. The rectified waveform can be obtained, and through the commutation access of two different windings, the isolated output can be realized by one transformer; according to the needs, a PFC unit can also be set to make a single-stage PFC converter. Unnecessary power, improve energy conversion efficiency and reduce the overall volume; and the coordinated control method is: divide a single cycle of the mains into multiple nodes, integrate the nodes into multiple time periods, and control the circuit according to the time period. Other units and components work to realize the process of regulating rectification, input and input, and the energy is adjusted with the PFC unit, so that when the PF value is high, the excess energy during the peak period is stored in the PFC unit, and the PFC unit is stored when it is underestimated. The stored energy is released as needed, thereby increasing the PF value and stabilizing the output; in conjunction with the buck-boost circuit and the control circuit, the PFC capacitor in the PFC unit can be controlled at a lower voltage to reduce the withstand voltage of the PFC capacitor. In turn, the service life is improved; some common components or circuits are subtracted from the design, and the conversion of primary energy is reduced, circuit loss is reduced, and the overall volume of the converter is reduced. The above greatly improves the practical value of the present invention.

The above-mentioned embodiments only represent one or more embodiments of the present invention, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the patent of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, which all belong to the protection scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

A half-wave symmetric converter, characterized in that it includes: a first half-wave rectifier circuit and a second half-wave rectifier circuit, wherein the first half-wave rectifier circuit and the second half-wave rectifier circuit are composed of diodes and switch tubes. any one or both of them;

The first half-wave rectifier circuit and the second half-wave rectifier circuit are connected in parallel at the AC input end, and a sine wave cycle of the AC input end is divided into a positive half cycle and a negative half cycle, and one half cycle is connected to the first half-wave rectifier In the circuit, the other half cycle of the AC input terminal is connected to the second half-wave rectifier circuit;

The other end of the two-way half-wave rectification circuit is electrically connected to the load or the converter, so as to form a complete input waveform for the alternating current, eliminating the need for primary rectification.
A half-wave symmetric converter according to claim 1, characterized in that, comprising: a control circuit and a potential energy conversion unit,

The control circuit is composed of switch tubes and/or diodes;

The potential energy conversion unit is an inductor or a transformer, and the potential energy conversion unit is provided with two groups;

The control circuit controls the connection of the first half-wave circuit and the potential energy conversion unit to form a first loop; the control circuit controls the connection of the second half-wave circuit and another potential energy conversion unit to form a second loop. Symmetrically form a half-wave symmetric converter;

The first loop and the second loop are set as any one of a boost circuit, a buck circuit, a boost circuit, a forward excitation circuit and a flyback circuit as required;

The two outputs of the first loop and the second loop are combined into one output circuit as required.
The half-wave symmetric converter according to claim 1, wherein the first half-wave rectifier circuit and the second half-wave rectifier circuit are commutated and electrically connected to different input windings of the same magnetic core transformer. The first half cycle and the second half cycle are alternated on the corresponding voltage waveform of the input voltage, and the secondary side forms an output voltage of the same phase.
The half-wave symmetric converter according to claim 1, further comprising: a PFC unit, the PFC unit is provided with an energy storage capacitor and at least one switch tube, and the position where the PFC unit is placed includes the following three A combination of one or more of:

Method 1, electrically connecting to the first half-wave rectifier circuit and/or the second half-wave rectifier circuit;

Method 2, electrically connecting between the windings of the first half-wave rectifier circuit and the second half-wave rectifier circuit;

The third method is to electrically connect between the winding and the ground.
The control method for a half-wave symmetric converter according to any one of claims 1-4, wherein the following nodes are divided by 0 to 360 degrees of the rectified sine wave as a cycle period:

T0, T0 is the lowest valley point of the voltage;

T1 and T1 are set in the voltage rising stage, the voltage at T1 is greater than that at T0, which is the low voltage boost point in the positive half cycle;

T2, T2 are set in the voltage rising stage, the voltage at T2 is greater than that at T1, which is the positive half-cycle boost high voltage point;

T3 and T3 are high voltage points in the positive half cycle, and the voltage at T3 is greater than that at T2;

T4, T4 are set in the voltage drop stage, the voltage at T4 is less than the voltage at T3, which is the high-voltage point of the positive half-cycle step-down;

T5, T5 are set in the voltage drop stage, the voltage at T5 is less than the voltage at T4, which is the low-voltage step-down point in the positive half cycle;

T1A and T1A are set in the voltage rising stage, the voltage at T1A is greater than that at T0A, which is the low voltage boost point in the negative half cycle;

T2A, T2A are set in the voltage rising stage, the voltage at T2A is greater than that at T1A, which is the negative half-cycle boost high voltage point;

T3A, T3A is the negative half cycle high voltage point, the voltage at T3A is greater than that at T2A;

T4A, T4A are set in the voltage drop stage, the voltage at T4A is less than the voltage at T3A, which is the negative half-cycle step-down high-voltage point;

T5A, T5A are set in the voltage drop stage, the voltage at T5A is less than the voltage at T4A, which is the low voltage step-down point in the negative half cycle;

Depending on the location of the PFC unit, the PFC unit is charged in the boost or high voltage stage;

In the trough stage: any one or more stages of the T4-T2 stage, the T4A-T2A stage, the T5-T1 stage, and the T5A-T1A stage, the PFC unit releases electric energy to fill the valley.
The control method of a half-wave symmetric converter according to claim 5, wherein when the PFC unit is arranged on the input bus, the time between T0-T3, T0-T3A, T1-T3, T1A-T3A , T2-T3, T2A-T3A boost stage, or one of the T2-T4, T2A-T4A high-voltage stages, the second loop is turned on for a long time or intermittently to charge the PFC unit.
The control method of a half-wave symmetric converter according to claim 5, characterized in that, when the PFC unit is arranged between the winding and the ground, at the peak time of the input sine wave, namely T2-T4 and T2A-T4A In the stage, the way to charge the PFC unit with energy storage is as follows:

When the voltage of the PFC unit is lower than the input voltage, the control unit controls the input to distribute energy to the PFC unit and the potential energy change unit as required;

In the voltage rising stage, the proportion of the energy input to the PFC unit is gradually increased, that is, the on-time of the PFC unit is increased;

In the voltage drop stage, the proportion of the energy input to the PFC unit is gradually reduced, that is, the on-time of the PFC unit is reduced;

The proportion of energy distribution is controlled by controlling the on-time to the PFC cell.
The method for controlling a half-wave symmetric converter according to claim 5, wherein in stages T2-T4 and T2A-T4A, when the voltage of the PFC unit is higher than the input voltage, the first turn-on The loop or the second loop stores the input energy into the potential energy conversion unit, and then closes the first loop or the second loop, the current of the potential energy conversion unit changes from increasing to decreasing, and the windings form back pressure, and then adjust it by any of the following methods:

Mode 1: Turn on the PFC unit, store the entire switching cycle in the PFC unit or directly transfer it to the secondary, and take one cycle or repeat more than one cycle to process in mode 1;

Method 2: Distribute the energy stored in the potential energy conversion unit for a single time to the PFC unit and output in turn;

The above distribution current increases as the input voltage increases, the storage ratio of the PFC unit increases, and as the input voltage decreases, the storage ratio to the PFC unit decreases.
A method for controlling a half-wave symmetric converter according to claim 5, characterized in that, at the time of the trough, that is, one of the stages T5-T1, T5A-T1A and/or T4-T2, T4A-T2A, the PFC The connection between the unit and the input is any one of parallel, series and series-parallel combination, and then combined with the input to the potential energy conversion unit to fill the valley and output, and passed to the output through the potential energy conversion unit.
The method for controlling a unipolar PFC according to claim 5, wherein an ACF module and a multi-channel output module are added as required.