A bridgeless double voltage PFC circuit

Abstract

The utility model discloses a kind of bridgeless voltage doubler PFC circuits, the bridgeless voltage doubler PFC circuit includes power factor inductance, switching unit, drive control module, first and second output capacitor and first, second freewheeling diode;Power factor inductance one end connects alternating current power positive pole, the other end is connected switching unit input end, first freewheeling diode anode respectively, switching unit output end connects alternating current power negative pole;First freewheeling diode cathode connects one end of first output capacitor, the other end of first output capacitor connects second output capacitor, the node of first output capacitor and second output capacitor is connected with alternating current power negative pole;The other end of second output capacitor connects second freewheeling diode anode, second freewheeling diode cathode connects first freewheeling diode anode;Drive control module output end connects switching unit control end, and output control signal controls switching device on-off. The utility model does not need rectifier bridge, converts single-phase voltage into high-voltage direct current, and efficiency is high, cost is low.

Description

Technical Field

[0001] This utility model relates to the field of power electronics technology, specifically to a bridgeless voltage multiplier PFC circuit. Background Technology

[0002] Switching power supplies have single-phase 220V and three-phase 380V AC inputs. To avoid injecting harmonics into the power grid, power factor correction (PFC) is required for both. In existing technologies, the output voltage of a single-phase 220V PFC is approximately 400V, and the output voltage of a three-phase PFC is approximately 700V. In scenarios requiring compatibility with both single-phase 220V and three-phase 380V inputs, the input range requirement for the subsequent DC / DC converter is too wide, severely impacting the efficiency of the switching power supply. Traditional single-phase 220V PFC typically employs a boost-type PFC circuit. If the output voltage is directly boosted to around 700V, the excessive boost ratio will cause the components to withstand very high voltage stress, leading to increased component costs, decreased efficiency, and worsened EMI, among other adverse consequences. Summary of the Invention

[0003] The purpose of this invention is to optimize and improve the single-phase PFC circuit and propose a bridgeless voltage multiplier PFC circuit topology, which can convert single-phase AC 220V to DC 750V after PFC correction, while eliminating the need for a rectifier bridge, reducing costs and improving efficiency.

[0004] The technical solution of this utility model is:

[0005] A bridgeless voltage multiplier PFC circuit includes a power factor inductor, switching devices, a drive control module, a first output capacitor, a second output capacitor, a first freewheeling diode, and a second freewheeling diode.

[0006] The switching unit consists of a first switching device and a second switching device of the same specification connected back to back, wherein the output terminal of the first switching device is connected to the input terminal of the second switching device; the control terminals of both switching devices are connected to the output terminal of the drive control module; the first terminal of the power factor inductor is connected to the positive terminal of the AC input power supply, the second terminal of the power factor inductor is connected to the input terminal of the first switching device of the switching unit and the anode of the first freewheeling diode, and the output terminal of the second switching device of the switching unit is connected to the negative terminal of the AC input power supply.

[0007] The cathode of the first freewheeling diode is connected to one end of the first output capacitor, and the other end of the first output capacitor is connected in series with the second output capacitor. The node where the first output capacitor and the second output capacitor are connected in series is connected to the negative terminal of the AC input power supply.

[0008] The other end of the second output capacitor is connected to the anode of the second freewheeling diode, and the cathode of the second freewheeling diode is connected to the anode of the first freewheeling diode.

[0009] The control terminal of the switching device is connected to the output terminal of the drive control module; the drive control module sends a control signal to the control terminal of the switching device to control the switching device's on / off state.

[0010] Furthermore, the bridgeless voltage multiplier PFC circuit also includes an input current sampling module and an output voltage sampling module; the input current sampling module is connected between the positive terminal of the AC input power supply and the first terminal of the power factor inductor, and is used to collect the input current of the AC power supply and send the sampled current signal to the drive control module; the output voltage sampling module is connected in parallel across the output terminals of the first output capacitor and the second output capacitor connected in series, and is used to sample the output voltage of the first output capacitor and the second output capacitor connected in series and send the voltage sampling signal to the drive control module.

[0011] Furthermore, the first and second switching devices of the same specification in the above-mentioned switching unit are both MOSFETs or IGBTs.

[0012] Beneficial effects of this utility model

[0013] The bridgeless voltage multiplier PFC circuit provided by this utility model converts single-phase 220V to DC 750V, and has the advantages of high efficiency, low voltage stress and low cost. Attached Figure Description

[0014] Figure 1 This is a circuit schematic diagram of an embodiment of the present invention;

[0015] Figure 2 The circuit diagram of this utility model is shown in the current guideline when the switching transistor is turned on during the positive half-cycle of the input AC signal.

[0016] Figure 3 The circuit diagram of this utility model is shown in the current guideline when the switching transistor is turned off during the positive half-cycle of the input AC circuit.

[0017] Figure 4 is a current flow diagram of the circuit of this utility model embodiment when the switching transistor is turned on during the negative half-cycle of the input AC.

[0018] Figure 5 is a circuit diagram showing the current flow of an embodiment of the present invention when the switching transistor is turned off during the negative half-cycle of the input AC circuit. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the present utility model and are not intended to limit the present utility model. Furthermore, the technical features involved in the various embodiments of the present utility model described below can be combined with each other as long as they do not conflict with each other. It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0020] The working principle of this utility model is explained below with reference to the embodiments shown in the appendix:

[0021] As shown in Figure 1, in this embodiment of the bridgeless voltage doubler PFC circuit, the bridgeless voltage doubler PFC circuit consists of an input current sampling module, a power factor inductor L1, a switching unit composed of a first switching transistor V1 and a second switching transistor V2, a first freewheeling diode D1, a first freewheeling diode D2, a first output capacitor C1, a first output capacitor C2, an output voltage sampling module, and a drive control module. The first switching transistor V1 and the second switching transistor V2 are both N-type MOS transistors.

[0022] The first terminal of the power factor inductor L1 is connected to the positive terminal AC_L of the AC input power supply. The second terminal of the power factor inductor L1 is connected to the input terminal of the first switching transistor V1 and the anode of the first freewheeling diode D1. The output terminal of the first switching transistor V1 is connected to the input terminal of the second switching transistor V2, and the output terminal of the second switching transistor V2 is connected to the negative terminal AC_N of the AC input power supply.

[0023] The cathode of the first freewheeling diode D1 is connected to one end of the first output capacitor C1, and the other end of the first output capacitor C1 is connected in series with the second output capacitor C2. The node where the first output capacitor C1 and the second output capacitor C2 are connected in series is connected to the negative terminal AC_N of the AC input power supply.

[0024] The other end of the second output capacitor C2 is connected to the anode of the second freewheeling diode D2, and the cathode of the second freewheeling diode D2 is connected to the anode of the first freewheeling diode D1.

[0025] The control terminals of the first switch V1 and the second switch V2 are connected to the output terminal of the drive control module.

[0026] The input current sampling module is connected between the positive terminal AC_L of the AC input power supply and the first terminal of the power factor inductor L1. The input current sampling module is used to collect the input current of the AC power supply and send the current sampling signal to the drive control module. The output voltage sampling module is connected in parallel to the output terminals of the first output capacitor C1 and the second output capacitor C2 connected in series. It is used to sample the output voltage of the first output capacitor C1 and the second output capacitor C2 connected in series and send the voltage sampling signal to the drive control module.

[0027] like Figure 2 As shown, when the AC input power supply is in the positive half-cycle, the drive control module sends a drive control signal to turn on the first switch V1 and the second switch V2. The current input to the positive terminal AC_L of the AC power supply flows through the power factor inductor L1, the first switch V1 and the second switch V2 to the negative terminal AC_N of the AC power supply, forming a loop. The power factor inductor L1 is charged and stores energy.

[0028] like Figure 3 As shown, when the drive control module sends a drive control signal to turn off the first switch V1 and the second switch V2, the power factor inductor L1 releases energy through the loop formed by the first freewheeling diode D1 and the first capacitor C1 with the negative terminal AC_N of the AC power supply, charging the first capacitor C1. The voltage across C1 is the sum of the effective voltage of the AC power supply and the output voltage of the inductor L1, which is 375V.

[0029] like Figure 4 As shown, when the AC input power supply is in the negative half-cycle, the drive control module sends a drive control signal to turn on the first switch V1 and the second switch V2. The current input to the negative terminal AC_N of the AC power supply flows through the second switch V2, the first switch V1 and the power factor inductor L1 to the positive terminal AC_L of the AC power supply, forming a loop. The power factor inductor L1 is charged and stores energy.

[0030] like Figure 5 As shown, when the drive control module sends a drive control signal to turn off the second switch V2 and the first switch V1, the power factor inductor L1 releases energy. The current forms a circuit through the positive terminal AC_L, the negative terminal AC_N of the power supply, the second capacitor C2, and the second freewheeling diode D2, charging the second capacitor C2. The voltage across the second capacitor C2 is the sum of the effective voltage of the AC power supply and the output voltage of the inductor L1, which is 375V.

[0031] Therefore, the voltage across the output terminals of the first output capacitor C1 connected in series with the second output capacitor C1 is 750V.

[0032] Since the MOS switch has a body diode, in the embodiments, the switching unit, which is composed of the first switch V1 and the second switch V2 of the N-type MOS transistor connected back to back, can reliably turn off after receiving the turn-off signal from the drive module when the power supply is in the positive and negative half-cycles.

[0033] The drive control module sends a drive control signal based on the current sampling signal from the input current sampling module and the output voltage sampling signal from the output voltage sampling module to control the duration of the switching transistor's on / off state. The on-time of the switching transistor determines the energy stored in the power factor inductor L1, thereby affecting its charging time for the first capacitor C2 and the second capacitor C2, as well as the peak voltage across them.

[0034] This novel circuit is suitable for power factor correction in switching power supplies with both 220V and 380V AC inputs, converting single-phase 220V AC voltage into 750V direct voltage. This invention reduces stress on power devices, has strong anti-interference capabilities, and is low in cost and highly efficient.

[0035] The above description is only a preferred embodiment of this utility model. It should be noted that due to the limitations of written expression, while there are objectively infinite specific structures, those skilled in the art can make several improvements, modifications, or changes without departing from the principle of this invention, and can also combine the above technical features in an appropriate manner. These improvements, modifications, changes, or combinations, or the direct application of the concept and technical solution of the utility model to other occasions without modification, should all be considered within the protection scope of this utility model.

Claims

1. A bridgeless voltage multiplier PFC circuit, characterized in that: Includes a power factor inductor, a switching unit, a drive control module, a first output capacitor, a second output capacitor, a first freewheeling diode, and a second freewheeling diode; The switching unit is composed of a first switching device and a second switching device of the same specification connected back to back, wherein the output terminal of the first switching device is connected to the input terminal of the second switching device; the control terminals of both switching devices are connected to the output terminal of the drive control module. The first terminal of the power factor inductor is connected to the positive terminal of the AC input power supply, the second terminal of the power factor inductor is connected to the input terminal of the first switching device of the switching unit and the anode of the first freewheeling diode, and the output terminal of the second switching device of the switching unit is connected to the negative terminal of the AC input power supply. The cathode of the first freewheeling diode is connected to one end of the first output capacitor, and the other end of the first output capacitor is connected in series with the second output capacitor. The node where the first output capacitor and the second output capacitor are connected in series is connected to the negative terminal of the AC input power supply. The other end of the second output capacitor is connected to the anode of the second freewheeling diode, and the cathode of the second freewheeling diode is connected to the anode of the first freewheeling diode. The control terminal of the switching unit is connected to the output terminal of the drive control module; the drive control module sends control signals to the control of the switching unit to control the switching unit's on / off state.

2. The bridgeless voltage multiplier PFC circuit according to claim 1, characterized in that, It also includes an input current sampling module and an output voltage sampling module; the input current sampling module is connected between the positive terminal of the AC input power supply and the first terminal of the power factor inductor, and is used to collect the input current of the AC power supply and send the sampled current signal to the drive control module; the output voltage sampling module is connected in parallel across the output terminals of the first output capacitor and the second output capacitor connected in series, and is used to sample the output voltage of the first output capacitor and the second output capacitor connected in series and send the voltage sampling signal to the drive control module.

3. The bridgeless voltage multiplier PFC circuit according to claim 1, characterized in that, The first and second switching devices of the same specification in the aforementioned switching unit are both MOSFETs or IGBTs.

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