Phase-shift PFC converter

Abstract

The utility model relates to the technical field of power electronics, and provides a phase-shift PFC converter, which is characterized in that a master control module is arranged to accurately control the on-off time and time sequence of a switching tube so as to realize the on-off control of a primary winding, voltage passes through an inductor through the control of a first switching tube Q1, the current of a first inductor L1 rises when the first switching tube Q1 is switched on, and the current of a second inductor L1 rises when the first switching tube Q1 is switched off. When the first switch tube Q1 is closed, the current stored in the first inductor L1 supplies power to the fourth capacitor C4 and the load through the fly-wheel diode D3, so that the inductor and the transformer T1 are ensured to have current, the condition of load cutoff is also avoided, and the power factor is improved. Meanwhile, shaping of the input voltage is achieved through the filtering effect of the capacitor, the power factor is further improved, and meanwhile higher harmonics of the input voltage are effectively restrained; the first diode D1 and the second diode D2 are arranged to assist in rectification input, and power supply of the first inductor L1 can be quickly recovered when the first switching tube Q1 is in a switching state.

Description

Technical Field

[0001] The utility model relates to the technical field of power electronics, in particular to a phase-shifted PFC converter. Background Art

[0002] The most widely used active PFC technology at present is a two-stage solution, namely active PFC boost converter + DC-DC converter.

[0003] The two-stage PFC converter uses two switches and two controllers. It is very mature in technology and has been widely used. However, this technical solution has disadvantages such as complex circuit topology and high cost. The two-stage PFC circuit also has two main disadvantages:

[0004] First, since there are two sets of devices, the number and cost of components are increased;

[0005] Second, the efficiency of the power supply will be reduced after the energy is converted twice.

[0006] Therefore, two-stage PFC circuits are generally used in circuits with higher power. For low-power applications, single-stage power factor correction circuits are generally used due to cost and volume limitations.

[0007] The PFC stage and DC-DC stage in the phase-shifted PFC AC-DC converter share a switch tube and a set of control circuits using PWM, while achieving power factor correction and output voltage regulation, with the advantages of simple circuit structure and low cost. Summary of the invention

[0008] The utility model provides a phase-shift PFC converter, which solves the technical problems that the existing two-stage PFC circuit has more components, resulting in a complex circuit structure and high cost, and has a large power loss, resulting in a low power factor.

[0009] To solve the above technical problems, the utility model provides a phase-shifted PFC converter, comprising a rectifier and filter module, a power conversion module and a PFC module, wherein the PFC module is connected in series between the rectifier and filter module and the power conversion module; the PFC module comprises a first inductor L1, a first diode D1 and a second diode D2, wherein the positive electrode of the first diode D1 is connected to a power input terminal AC1 and one input terminal of the rectifier and filter module, and the negative electrode is connected to the first inductor L1, and the positive electrode of the second diode D2 is connected to the power input terminal AC2 and the other input terminal of the rectifier and filter module, and the negative electrode is connected to the first inductor L1.

[0010] In a further implementation scheme, the PFC module also includes a second capacitor C2 and a third capacitor C3, one end of the second capacitor C2 is connected to the power input terminal AC1, and the other end is connected to an input terminal of the rectifier and filter module; one end of the second capacitor C2 is connected to the power input terminal AC2, and the other end is connected to the other output terminal of the rectifier and filter module.

[0011] In a further implementation scheme, the rectifier and filter module includes a rectifier bridge BD1 and a first capacitor C1, the two input ends of the rectifier bridge BD1 are respectively connected to the power input end AC1 and the power input end AC2, one output end of the rectifier bridge BD1 is grounded, the other output end is connected to the first capacitor C1, and the other output end of the rectifier bridge BD1 is electrically connected to the power conversion module.

[0012] In a further embodiment, a post-stage rectifier module is further included, and the post-stage rectifier module is connected to the output end of the power conversion module.

[0013] In a further implementation scheme, the post-stage rectifier module includes a freewheeling diode D3, a fourth capacitor C4 and a first resistor R1, the positive electrode of the fourth capacitor C4 is connected to the negative electrode of the freewheeling diode D3, and the negative electrode is grounded, the fourth capacitor C4 is connected in parallel with the first resistor R1 to form an RC filtering network; the positive electrode of the freewheeling diode D3 is connected to the output end of the power conversion module, and the negative electrode is connected to the load through the RC filtering network.

[0014] In a further embodiment, the utility model further comprises a switch module and a main control module, wherein the main control module is connected to the control end of the switch module, and the switch module is connected to the input end of the power conversion module.

[0015] In a further embodiment, the switch module includes a first switch tube Q1 and a second resistor R2, the first end of the first switch tube Q1 is grounded through the second resistor R2, the second end is connected to the input end of the power conversion module, and the control end is connected to the main control module.

[0016] In a further embodiment, the power conversion module is a transformer T1, including a primary winding and a secondary winding, the primary winding includes a connection terminal a, a connection terminal b and a connection terminal c, the connection terminal a is connected to the rectifier and filter module, the connection terminal b is connected to the first inductor L1, and the connection terminal c is connected to the output terminal of the switch module; the secondary winding is connected to the post-stage rectifier module as the output terminal.

[0017] In a further embodiment, the first switch tube Q1 is a triode or a MOS tube.

[0018] In a further embodiment, the main control module is a power management chip.

[0019] The beneficial effects of the utility model are as follows:

[0020] The main control module is set to accurately control the on-off time and timing of the switch tube, thereby realizing the on-off control of the primary winding. The voltage passes through the inductor through the control of the first switch tube Q1. When the first switch tube Q1 is turned on, the current of the first inductor L1 rises. When the first switch tube Q1 is turned off, the current stored in the first inductor L1 is supplied to the fourth capacitor C4 and the load through the freewheeling diode D3. In this way, the inductor and transformer T1 are guaranteed to have current, and the load is prevented from being cut off, thereby improving the power factor. At the same time, the filtering effect of the capacitor is used to realize the shaping of the input voltage, further improving the power factor, and effectively suppressing the high-order harmonics of the input voltage; the first diode D1 and the second diode D2 are set to assist the rectifier input, which can realize the rapid recovery of the power supply to the first inductor L1 when the first switch tube switches state. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a system framework diagram of a phase-shifted PFC converter provided by an embodiment of the utility model;

[0022] Figure 2 The utility model embodiment provides Figure 1 Part of the hardware circuit diagram in;

[0023] Among them: rectification and filtering module 1, power conversion module 2, PFC module 3, post-stage rectification module 4, switch module 5, main control module 6. DETAILED DESCRIPTION

[0024] The following is a detailed explanation of the implementation mode of the present invention in conjunction with the accompanying drawings. The embodiments are provided for illustrative purposes only and cannot be understood as limitations on the present invention. The accompanying drawings are provided for reference and illustration only and do not constitute limitations on the scope of patent protection of the present invention, because many changes can be made to the present invention without departing from the spirit and scope of the present invention.

[0025] The present invention provides a phase-shifted PFC converter. Figure 1 , Figure 2As shown, in this embodiment, a rectifier and filter module 1, a power conversion module 2 and a PFC module 3 are included, and the PFC module 3 is connected in series between the rectifier and filter module 1 and the power conversion module 2; the PFC module 3 includes a first inductor L1, a first diode D1, and a second diode D2, the positive electrode of the first diode D1 is connected to the power input terminal AC1 and one input terminal of the rectifier and filter module 1, and the negative electrode is connected to the first inductor L1, the positive electrode of the second diode D2 is connected to the power input terminal AC2 and the other input terminal of the rectifier and filter module 1, and the negative electrode is connected to the first inductor L1.

[0026] In this embodiment, the PFC module 3 also includes a second capacitor C2 and a third capacitor C3, one end of the second capacitor C2 is connected to the power input terminal AC1, and the other end is connected to an input terminal of the rectifier and filter module 1; one end of the second capacitor C2 is connected to the power input terminal AC2, and the other end is connected to the other output terminal of the rectifier and filter module 1.

[0027] In this embodiment, the rectifier and filter module 1 includes a rectifier bridge BD1 and a first capacitor C1. The two input ends of the rectifier bridge BD1 are respectively connected to the power input end AC1 and the power input end AC2. One output end of the rectifier bridge BD1 is grounded, and the other output end is connected to the first capacitor C1. The other output end of the rectifier bridge BD1 is electrically connected to the power conversion module 2.

[0028] In this embodiment, a post-stage rectifying module 4 is further included, and the post-stage rectifying module 4 is connected to the output end of the power conversion module 2 .

[0029] In this embodiment, the post-stage rectifier module 4 includes a freewheeling diode D3, a fourth capacitor C4 and a first resistor R1, the positive electrode of the fourth capacitor C4 is connected to the negative electrode of the freewheeling diode D3, and the negative electrode is grounded, the fourth capacitor C4 is connected in parallel with the first resistor R1 to form an RC filtering network; the positive electrode of the freewheeling diode D3 is connected to the output end of the power conversion module 2, and the negative electrode is connected to the load through the RC filtering network.

[0030] In this embodiment, the utility model further comprises a switch module 5 and a main control module 6 , wherein the main control module 6 is connected to the control end of the switch module 5 , and the switch module 5 is connected to the input end of the power conversion module 2 .

[0031] In this embodiment, the main control module 6 is a processing chip with a signal driving function, such as a power management chip. According to actual needs, a sampling feedback module and an overvoltage and undervoltage protection module (not shown in the figure) connected to the main control module 6 can also be set, wherein the sampling feedback module is connected to the post-stage rectifier module 4, and the overvoltage and undervoltage protection module is connected to the rectifier and filter module 1.

[0032] In this embodiment, the switch module 5 includes a first switch tube Q1 and a second resistor R2, the first end of the first switch tube Q1 is grounded through the second resistor R2, the second end is connected to the input end of the power conversion module 2, and the control end is connected to the main control module 6.

[0033] In this embodiment, the first switch tube Q1 is a triode or a MOS tube.

[0034] In this embodiment, the power conversion module 2 is a transformer T1, including a primary winding and a secondary winding, the primary winding includes a connection terminal a, a connection terminal b and a connection terminal c, the connection terminal a is connected to the rectifier and filter module 1, the connection terminal b is connected to the first inductor L1, and the connection terminal c is connected to the output terminal of the switch module 5; the secondary winding is connected to the post-stage rectifier module 4 as the output terminal.

[0035] Taking the N-channel MOS tube as an example, the working principle of this embodiment is as follows:

[0036] The main control module 6 outputs a high level to drive the first switch tube Q1 to turn on. At the moment the first switch tube Q1 is turned on, the voltage passes through the inductor, and the current of the first inductor L1 increases and stores energy.

[0037] The main control module 6 outputs a low level to turn off the first switch tube Q1. At this time, the current in the first inductor L1 flows through the first inductor L1 and the primary winding of the transformer T1 to charge the first capacitor C1, and at the same time charges the load through the secondary winding of the transformer T1 and the post-stage rectifier module 4.

[0038] The beneficial effects of the utility model are as follows:

[0039] The main control module 6 is set to accurately control the on-off time and timing of the switch tube, thereby realizing the on-off control of the primary winding. The voltage passes through the inductor through the control of the first switch tube Q1. When the first switch tube Q1 is turned on, the current of the first inductor L1 rises. When the first switch tube Q1 is turned off, the current stored in the first inductor L1 is supplied to the fourth capacitor C4 and the load through the freewheeling diode D3, thereby ensuring that the inductor and transformer T1 have current, and avoiding the situation of load current interruption, thereby improving the power factor. At the same time, the filtering effect of the capacitor is used to realize the shaping of the input voltage, further improve the power factor, and effectively suppress the high-order harmonics of the input voltage; the first diode D1 and the second diode D2 are set to assist the rectifier input, which can realize the rapid recovery of the power supply to the first inductor L1 when the first switch tube switches state.

[0040] After improving the power factor, you can also:

[0041] 1. Reduce power loss: By improving the power factor, the PFC circuit can reduce the current and voltage in the circuit, reduce the resistance, inductance, and capacitance losses in the wires, and thus reduce the power loss in the line.

[0042] 2. Improve the energy efficiency of the power system: By improving the power factor, the PFC circuit can effectively reduce the waste of electric energy and improve the energy efficiency of the power system.

[0043] 3. Reduce the load on the power system: Improve the power factor to ease the load on the power system, reduce the risk of line overload, and improve the stability and reliability of the power system.

[0044] 4. Improve the quality of power supply: The improvement of power factor can reduce the negative impact of harmonics, voltage fluctuations, etc. on the power supply. The PFC circuit can not only improve the quality of power supply, but also reduce interference with other electronic equipment and improve the stability of the entire power system.

[0045] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principle of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A phase-shifted PFC converter, characterized in that: It includes a rectifier and filter module, a power conversion module and a PFC module, wherein the PFC module is connected in series between the rectifier and filter module and the power conversion module; the PFC module includes a first inductor L1, a first diode D1 and a second diode D2, wherein the positive electrode of the first diode D1 is connected to the power input terminal AC1 and one input terminal of the rectifier and filter module, and the negative electrode is connected to the first inductor L1, and the positive electrode of the second diode D2 is connected to the power input terminal AC2 and the other input terminal of the rectifier and filter module, and the negative electrode is connected to the first inductor L1.

2. A phase-shifted PFC converter according to claim 1, characterized in that: The PFC module also includes a second capacitor C2 and a third capacitor C3, one end of the second capacitor C2 is connected to the power input terminal AC1, and the other end is connected to an input end of the rectifier and filter module; one end of the second capacitor C2 is connected to the power input terminal AC2, and the other end is connected to the other output end of the rectifier and filter module.

3. A phase-shifted PFC converter as claimed in claim 2, characterized in that: The rectifier and filter module includes a rectifier bridge BD1 and a first capacitor C1. The two input ends of the rectifier bridge BD1 are respectively connected to the power input end AC1 and the power input end AC2. One output end of the rectifier bridge BD1 is grounded, and the other output end is connected to the first capacitor C1. The other output end of the rectifier bridge BD1 is electrically connected to the power conversion module.

4. A phase-shifted PFC converter according to claim 1, characterized in that: It also includes a post-stage rectifying module, which is connected to the output end of the power conversion module.

5. A phase-shifted PFC converter as claimed in claim 4, characterized in that: The post-stage rectifier module includes a freewheeling diode D3, a fourth capacitor C4 and a first resistor R1. The positive electrode of the fourth capacitor C4 is connected to the negative electrode of the freewheeling diode D3 and the negative electrode is grounded. The fourth capacitor C4 is connected in parallel with the first resistor R1 to form an RC filter network. The positive electrode of the freewheeling diode D3 is connected to the output end of the power conversion module, and the negative electrode is connected to the load through the RC filter network.

6. A phase-shifted PFC converter as claimed in claim 4, characterized in that: It also includes a switch module and a main control module. The main control module is connected to the control end of the switch module, and the switch module is connected to the input end of the power conversion module.

7. A phase-shifted PFC converter as claimed in claim 6, characterized in that: The switch module includes a first switch tube Q1 and a second resistor R2. The first end of the first switch tube Q1 is grounded through the second resistor R2, the second end is connected to the input end of the power conversion module, and the control end is connected to the main control module.

8. A phase-shifted PFC converter as claimed in claim 6, characterized in that: The power conversion module is a transformer T1, including a primary winding and a secondary winding, the primary winding includes a connection terminal a, a connection terminal b and a connection terminal c, the connection terminal a is connected to the rectifier and filter module, the connection terminal b is connected to the first inductor L1, and the connection terminal c is connected to the output terminal of the switch module; the secondary winding is connected to the post-stage rectifier module as the output terminal.

9. A phase-shifted PFC converter according to claim 7, characterized in that: The first switch tube Q1 is a triode or a MOS tube.

10. A phase-shifted PFC converter as claimed in claim 6, characterized in that: The main control module is a power management chip.

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