Output-power-adjustable active PFC+ soft switch power converter and conversion method thereof

A power converter and output power technology, which is applied in the output power conversion device, regulating electrical variables, converting DC power input to DC power output, etc. problems such as poor consistency, to achieve the effect of high power conversion efficiency, low implementation cost, and reliable performance

Active Publication Date: 2016-10-26
杭州重芯力科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] The existing medium and high-power high-efficiency switching power supplies mostly use LLC resonance mode and phase-shift full-bridge soft switching mode. However, the input voltage range of LLC resonance mode is not wide, the dynamic is poor, and the resonance leakage inductance is not easy to control (poor product consistency). The technology is far from mature; the phase-shift full-bridge soft switching mode has a large primary-side circulation loss, and it is difficult to realize soft switching in the lagging arm at light load (need to add a more complicated auxiliary circuit), the duty cycle is lost, the utilization rate of the power tube is low, and the loss increases
[0003] In terms of power devices, although the bipolar transistor chip has high utilization rate, low price, mature technology, and strong load capacity, it is difficult to drive (switching speed is slow and varies with the load), and the existing soft-switching power supply control chips all use The higher cost MOSFET (or IGBT) is the driving object, so the high-efficiency switching power supply with medium and high power has become the stage of MOSFET
However, due to the large conduction loss of the power MOSFET (especially prominent at high current P=Id 2 *Ron), making it a bottleneck for further power efficiency improvements
[0004] Bridge (half-bridge or full-bridge) power converters can work well in the soft switching state through control, and are also suitable for bipolar transistor applications. However, since the duty cycle cannot be adjusted to control the output voltage, it can only be Simple application to electronic transformers

Method used

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  • Output-power-adjustable active PFC+ soft switch power converter and conversion method thereof
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  • Output-power-adjustable active PFC+ soft switch power converter and conversion method thereof

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Experimental program
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Effect test

Embodiment 1

[0019] Embodiment 1: refer to image 3 . The front stage adopts an active PFC circuit with adjustable output, and the PFC circuit in this embodiment adopts a BOOST circuit. The purpose of power factor correction is to make the waveform of the current I follow the input voltage V, and at the same time output the voltage V_pfc. If the phases of the input current and the input voltage are equal, the load can be equivalent to a resistor R. Therefore: V=I×R, for the BOOST circuit, the relationship between its input voltage Vin, output voltage V_pfc and duty cycle D is:

[0020] V _ p f c = V 1 - D

[0021] Substitute V=I×R into:

[0022] V_pfc*(1-D)=I*R

[0023] therefore:

[0024] V _ p f c = I * R ...

Embodiment 2

[0028] Embodiment 2: with reference to attached Figure 4 . On the basis of embodiment 1, utilize existing digital processor unit price to be cheap, develop simply, multi-channel input and output, can carry out logic operation, the characteristic of time sequence control, the PFC controller in the active PFC pre-stage uses digital processor instead.

[0029] The feedback circuit and current sampling convert the analog signal into a digital signal through the analog-to-digital converter and transmit it to the digital processor. The digital processor calculates the duty cycle of the PFC circuit based on the feedback data, so that the active PFC front stage can adjust the output voltage. At the same time complete the power factor correction function. Wherein, the analog-to-digital converter may utilize an internal analog-to-digital converter of the digital processor.

Embodiment 3

[0030] Embodiment 3: with reference to attached Figure 5 . The power converter of this embodiment adopts a servo-controlled half-bridge circuit, and the power devices work in a soft switching state.

[0031] Let the conduction time of the switch tube be t. The active PFC pre-stage output voltage is V_pfc, and the half-bridge midpoint voltage is V_mid. Assuming that Q2 is turned on, the midpoint voltage V_mid is equal to V_pfc.

[0032] State 1: According to the set time t, the control circuit turns off Q1, and the internal timer starts counting at the same time. Due to the existence of the resonant capacitor C3, the midpoint voltage V_mid is equal to V_pfc, and Q1 is turned off at zero voltage. The resonant capacitor C3 is discharged through the transformer T1, and the circuit enters a resonant state.

[0033] State 2: The mid-point voltage V_mid resonates to zero. Since the leakage inductance energy of T1 has not been exhausted, the current of T1 is still from left to ri...

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PUM

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Abstract

The invention relates to an output-power-adjustable active PFC+ bridge-type soft switch power converter and a conversion method thereof, wherein the output-power-adjustable active PFC+ bridge-type soft switch power converter is completely different from a present LLC resonant mode and a phase shift full-bridge soft switch mode and suitable for a bipolar transistor applied soft switch mode, and especially a medium and high power efficient switching power supply is formed by the output-power-adjustable active PFC and the power converter. The output-power-adjustable active PFC is used for PFC control and output power adjustment. The power converter is used for energy conversion and separation from the PFC to load and output of sampling feedback to the active PFC. The advantages are that the implementation cost is low, development is simple and performance is reliable; and the power conversion efficiency is more than 90%, and output power of the power supply converter can be automatically adjusted according to the change of the load.

Description

technical field [0001] The invention relates to an active PFC+bridge soft switch with adjustable output power which is completely different from the current LLC resonance mode and phase-shift full-bridge soft switch mode and is suitable for the soft switch voltage stabilization mode applied to bipolar transistors A power converter and a conversion method, especially a high-efficiency switching power supply of medium and high power, belong to the field of switching power supply manufacturing. Background technique [0002] The existing medium and high-power high-efficiency switching power supplies mostly use LLC resonance mode and phase-shift full-bridge soft switching mode. However, the input voltage range of LLC resonance mode is not wide, the dynamic is poor, and the resonance leakage inductance is not easy to control (poor product consistency). The technology is far from mature; the phase-shift full-bridge soft switching mode has a large primary-side circulation loss, and ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M3/156H02M1/42H02M1/00
CPCH02M1/00H02M1/42H02M3/156H02M1/0058Y02B70/10Y02P80/10
Inventor 余思明
Owner 杭州重芯力科技有限公司
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