CN203537228U - Digital PFC (Power Factor Correction) control system for power supply product - Google Patents

Abstract

The utility model discloses a digital PFC (Power Factor Correction) control system for a power supply product. The system comprises an air switch, an EMC filter, a rectifier bridge, a BOOST step-up circuit and a DSPIC single-chip microcomputer. An input terminal of the EMC filter is connected with an input power supply through the air switch, and an output terminal of the EMC filter is connected with an input terminal of the BOOST step-up circuit through the rectifier bridge. The DSPIC single-chip microcomputer is connected with a control terminal of the BOOST step-up circuit. The DSPIC single-chip microcomputer samples input voltage, input current and output voltage from the BOOST step-up circuit, performs digital signal processing, and outputs a PWM signal to the BOOST step-up circuit to control the BOOST step-up circuit. The digital PFC control system provided by the utility model has the advantages of high stability, on-line programming, simple circuit, convenient debugging, high flexibility, low cost, abrupt load change control and excellent performance, and is capable of significantly increasing the PF value and THD value of the system circuit.

Description

A kind of power supply product digital pfc control system

Technical field

The utility model relates to a kind of digital pfc control technology, special relevant with the digital pfc control system of power supply product.

Background technology

Now, power supply product PFC(Power Factor Correction on the market, i.e. power factor correction) control circuit mainly adopts simulation PFC control program, and simulation PFC control circuit is complicated, and cost is high, very flexible, stability can be affected by chip performance.Also there is on the market a kind of digital pfc control program, as shown in Figure 1, adopt dicyclo (input voltage ring, input current ring) high frequency to control, the cycle of Voltage loop and electric current loop is the same, all fast cycle (unit is microsecond rank), the method is controlled unstable to load changing, and PF value (power factor) and THD value (total harmonic distortion degree) poor.

Utility model content

The purpose of this utility model is to provide a kind of power supply product digital pfc control system, and it is high that it has stability, can online programming, and circuit is simple, convenient debugging, flexibility is strong, and cost is low, load changing is controlled, and performance is remarkable, significantly improves the advantages such as the PF value of circuit system and THD value.

In order to reach above-mentioned purpose, solution of the present utility model is:

A power supply product digital pfc control system, is comprised of air switch, EMC filter, rectifier bridge, BOOST booster circuit and DSPIC single-chip microcomputer; The input of EMC filter is connected with input power by air switch, the output of EMC filter is connected with the input of BOOST booster circuit by rectifier bridge, DSPIC single-chip microcomputer is connected with the control end of BOOST booster circuit, DSPIC single-chip microcomputer is from input sampling input voltage and the input current of BOOST booster circuit, DSPIC single-chip microcomputer, from the output sampling and outputting voltage of BOOST booster circuit, is exported PWM(pulse width modulation by Digital Signal Processing) signal is to BOOST booster circuit and control BOOST booster circuit.

The input of described BOOST booster circuit is also connected with the PFC zero passage detection pin of DSPIC single-chip microcomputer.

Adopt after such scheme, the mode that the utility model adopts monocycle (output-voltage loop) to combine with dicyclo (input voltage ring, input current ring), can online programming, circuit is simple, convenient debugging, and flexibility is strong, cost is low, when the effect of monocycle is load changing, play the effect of voltage stabilizing, performance is remarkable, and the effect of dicyclo is to improve power factor PF value and total harmonic distortion degree THD value.

Accompanying drawing explanation

Fig. 1 is that existing digital pfc is controlled schematic diagram;

Fig. 2 is structural representation of the present utility model;

Fig. 3 is that dicyclo of the present utility model is controlled schematic diagram;

Fig. 4 is that monocycle of the present utility model is controlled schematic diagram;

Fig. 5 is control principle block diagram of the present utility model.

Embodiment

As shown in Figure 2, a kind of power supply product digital pfc control system that the utility model discloses, is comprised of air switch 1, EMC filter 2, rectifier bridge 3, BOOST booster circuit 4 and DSPIC single-chip microcomputer 5.Input power 176-264Vac is connected with the input of EMC filter 2 by air switch 1, the output of EMC filter 2 is connected with the input of BOOST booster circuit 4 by rectifier bridge 3, DSPIC single-chip microcomputer 5 is connected with the control end of BOOST booster circuit 4, DSPIC single-chip microcomputer 5 is from input sampling input voltage and the input current of BOOST booster circuit 4, DSPIC single-chip microcomputer 5 is from the output sampling and outputting voltage of BOOST booster circuit 4, pass through Digital Signal Processing, output pwm signal is to BOOST booster circuit 4, and controls BOOST booster circuit 4.The input of BOOST booster circuit 4 is also connected with the PFC zero passage detection pin of DSPIC single-chip microcomputer 5.

Coordinate shown in Fig. 3 and Fig. 4, the mode that the utility model adopts monocycle (output-voltage loop) to combine with dicyclo (input voltage ring, input current ring), the effect of dicyclo is to improve power factor (PF) PF and THD, plays the effect of voltage stabilizing when the effect of monocycle is load changing.In dicyclo, respectively control cycle of ring is different by setting for the utility model, and the Voltage loop control cycle in dicyclo is slow cycle T_v2, and be half of input civil power cycle, unit be a millisecond rank, the control cycle of electric current loop is the fast periodt_i2, unit is microsecond rank.During monocycle, the control cycle of output-voltage loop is the fast periodt_v1, unit is microsecond rank.

Coordinate shown in Fig. 5, during the utility model dicyclo, the control cycle of electric current loop ist_i2,according to the control cycle of commissioning experience electric current loopt_i2than very fast, be microsecond rank, the control cycle of Voltage loop ist_v2=t_{civil power}/ 2=1/2f_{civil power}, why allow the Voltage loop control cycle be half of civil power cycle, because civil power becomes steamed bun ripple by original sine wave after rectifier bridge, frequency is original twice, the cycle of Voltage loop is steamed bun wave period during dicyclo, Voltage loop output valvev_pIthrough an input voltage cyclet_v2just adjust once input voltagev_aCitself be a sine curve, thereby guaranteeing that both multiply each other is multiplied by electric voltage feed forward mean value again and draw electric current loop input current set pointi_aCREFjust sinusoidal variations be can be, corresponding power factor (PF) PF and THD improved.And, Voltage loop output valvev_pIeach calculating is all to calculate in input voltage zero crossing, thereby guarantees that each input current cycle has corresponding Voltage loop output valve at the very startv_pI.The detailed process of double-ring mode is: software output voltage set pointv_dCREFwith output voltage sampled value V_dCrelatively draw an error amountv_eRR, through PI, computing draws a Voltage loop output valvev_pI, calculate input current set pointi_aCREF=K_m* V_pI/ V_aVG²,v_aVGfor input voltage mean value, input current set pointi_aCREFwith input current sampled valuei_aCcompare output error valuei_eRR, through PI, computing draws electric current loop output valvei_pIassignment is to PWM duty ratio.

During monocycle, the control cycle of output-voltage loop ist_v1,t_v1value be microsecond rank.Introducing monocycle Voltage loop is because in the time of load changing, especially heavy duty lightens and carries or unloaded time, busbar voltage can be exported high pressure, and introducing monocycle can solve voltage stabilizing in output high pressure and, in rated voltage, be switched to again dicyclo mode of operation after working stability.The detailed process of monocycle pattern is software output voltage set pointv_dCREFwith output voltage sampled value V_dCrelatively draw an error amountv_eRR, through PI, computing draws a Voltage loop output valvev_pIassignment is to PWM duty ratio.

Claims (2)

1. a power supply product digital pfc control system, is characterized in that: air switch, EMC filter, rectifier bridge, BOOST booster circuit and DSPIC single-chip microcomputer, consist of; The input of EMC filter is connected with input power by air switch, the output of EMC filter is connected with the input of BOOST booster circuit by rectifier bridge, DSPIC single-chip microcomputer is connected with the control end of BOOST booster circuit, DSPIC single-chip microcomputer is from input sampling input voltage and the input current of BOOST booster circuit, DSPIC single-chip microcomputer is from the output sampling and outputting voltage of BOOST booster circuit, by Digital Signal Processing output pwm signal to BOOST booster circuit and control BOOST booster circuit.

2. a kind of power supply product digital pfc control system as claimed in claim 1, is characterized in that: the input of described BOOST booster circuit is also connected with the PFC zero passage detection pin of DSPIC single-chip microcomputer.

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