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CN112217387A - High Efficiency and High PF Value DCM Boost PFC Converter with Variable Inductance - Google Patents

High Efficiency and High PF Value DCM Boost PFC Converter with Variable Inductance Download PDF

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Publication number
CN112217387A
CN112217387A CN202010869908.1A CN202010869908A CN112217387A CN 112217387 A CN112217387 A CN 112217387A CN 202010869908 A CN202010869908 A CN 202010869908A CN 112217387 A CN112217387 A CN 112217387A
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output
resistor
input
circuit
algorithm module
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Inventor
杨坚
姚凯
高阳
李家镇
王泽松
刘乐
刘劲滔
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Nanjing University of Science and Technology
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Nanjing University of Science and Technology
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
    • H02M1/4208—Arrangements for improving power factor of AC input
    • H02M1/4225—Arrangements for improving power factor of AC input using a non-isolated boost converter
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
    • H02M7/02—Conversion of AC power input into DC power output without possibility of reversal
    • H02M7/04—Conversion of AC power input into DC power output without possibility of reversal by static converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
    • H02M7/02—Conversion of AC power input into DC power output without possibility of reversal
    • H02M7/04—Conversion of AC power input into DC power output without possibility of reversal by static converters
    • H02M7/12—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/21—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/217—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H02M1/0012—Control circuits using digital or numerical techniques
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H02M1/0038—Circuits or arrangements for suppressing, e.g. by masking incorrect turn-on or turn-off signals, e.g. due to current spikes in current mode control
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)

Abstract

The invention discloses a high-efficiency high-Power Factor (PF) value DCM Boost PFC (inductive current discontinuous mode Boost power factor correction) converter with variable inductance, which comprises a main power circuit and a control circuit, wherein the control circuit comprises an input voltage sampling circuit, an output voltage sampling circuit, a first amplitude limiting circuit, a second amplitude limiting circuit, a Digital Signal Processor (DSP) module, an isolation driving circuit and a controlled current source circuit; an ADC (analog-to-digital conversion) submodule of the DSP module collects input voltage and output voltage data, performs related algorithm processing, and an EPWM (enhanced pulse width modulation) submodule outputs a duty ratio signal of a converter to drive a switching tube; and outputting a voltage signal required by controlling the variable inductor by a DAC (digital-to-analog conversion) submodule. The invention improves the power factor of the converter, improves the switching period utilization rate of the converter, reduces the peak value of input current, reduces the conduction loss of a switching tube and improves the efficiency of the converter.

Description

High-efficiency high-PF-value DCM Boost PFC converter with variable inductor
Technical Field
The invention relates to the technical field of alternating current-direct current converters of electric energy conversion devices, in particular to a high-efficiency high-PF-value DCMBoostPFC converter with variable inductance.
Background
The Power Factor Correction (PFC) converter can reduce input current harmonic waves, improve input power factors and improve electric energy quality. Wherein, DCM boost PFC converter is because of boost switch tube QbZero current turn-on, boost diode DbThe method has no reverse recovery, and is widely applied to medium and small power occasions. The traditional DCM boost PFC converter controlled by a fixed duty ratio has constant switching frequency and simple control, but the inductive current in the switching period of the DCM boost PFC converter has an intermittent stage, so that the peak value of the inductive current is high, the input power factor is low, and the efficiency of the converter is low. Yaoka proposed in ANovel Control Scheme of dcmboost pfc Converter that PF value of the Converter could be increased to approximately 1 by variable duty ratio Control, and that the peak value of the inductor current of the Converter could be reduced, resulting in improved efficiency. However, there is still a discontinuous phase of the inductor current in the switching cycle.
If the proportion of the discontinuous phase of the inductive current in one switching period can be further increased in each switching period, even close to complete utilization, the peak value of the inductive current is further reduced, and further the current stress is reduced and the conversion efficiency is improved.
Disclosure of Invention
The invention aims to provide a high-efficiency DCMBoostPFC converter which is simple in control circuit, good in control effect and variable in boost inductance, and the PF value and the switching period utilization rate are improved to 1 in the whole 90V-264 VAC input voltage range.
Technical solution for achieving the purpose of the inventionThe solution is as follows: a high-efficiency high-PF-value DCMBoostPFC converter with variable inductance comprises a main power circuit and a control circuit, wherein the main power circuit comprises an input voltage source vinEMI filter, rectifying circuit RB, LC filter, variable boost inductor LbBoost switching tube QbAnd a boost diode DbAn output capacitor CoAnd a load RLd(ii) a The control circuit comprises an input voltage sampling circuit, an output voltage sampling circuit, a first amplitude limiting circuit, a second amplitude limiting circuit, a DSP module, an isolation driving circuit and a controlled current source circuit;
the main power circuit is respectively connected with the input voltage sampling circuit, the output voltage sampling circuit, the controlled current source circuit and the isolation driving circuit; the input voltage sampling circuit is connected with the first amplitude limiting circuit; the output voltage sampling circuit is connected with the second amplitude limiting circuit; the DSP module is respectively connected with the first amplitude limiting circuit, the second amplitude limiting circuit, the controlled source circuit and the isolation driving circuit;
the ADC submodule of the DSP module collects input voltage and output voltage data, performs related algorithm processing, the EPWM submodule outputs a driving signal of a switching tube, and the DAC submodule outputs a voltage signal required by controlling the variable inductor.
Further, the input voltage source vinThe output port of the EMI filter is connected with the input port of a rectifier bridge RB, the output positive port of the rectifier bridge RB is connected with the input positive port of the LC filter, the output negative port of the rectifier bridge RB is connected with the input negative port of the LC filter, the output positive port of the LC filter is connected with a variable boost inductor LbIs connected with the output negative port of the LC filter and the boost switching tube QbSource electrode and output capacitor CoNegative terminal of and load RLdIs connected with the negative terminal of the LC filter, the negative port of the LC filter is a reference potential zero point, and the variable boost inductor LbAnd the other end of the diode D and a boost diode DbPositive terminal and boost switching tube QbIs connected to the drain of the variable boost inductor LbThe control end of the voltage boosting switch tube Q is connected with a controlled current source circuitbAnd a gate ofThe isolation driving circuit is connected; boost diode DbNegative terminal of and output capacitor CoAnd a load RLdIs connected to the positive terminal of the load RLdThe voltage at both ends is output voltage Vo(ii) a Load RLdBoth ends of the output voltage sampling circuit are connected with the output voltage sampling circuit.
Furthermore, the positive input end of the input voltage sampling circuit passes through a current limiting resistor R3AC input voltage v to main power circuitinIs connected with the reverse input end of the input voltage sampling circuit and is directly connected with the alternating current input voltage v of the main power circuitinThe output port C of the input voltage sampling circuit is connected with the input port 1 of the second amplitude limiting circuit, and the output port 2 of the second amplitude limiting circuit is connected with the input port ADCA1 of the DSP module; the positive input end of the output voltage sampling circuit passes through a current limiting resistor R16With the output voltage V of the main power circuitoIs connected with the positive port of the main power circuit, and the reverse input end of the output voltage sampling circuit is directly connected with the output voltage V of the main power circuitoThe output port F of the output voltage sampling circuit is connected with the input port 3 of the first amplitude limiting circuit, and the output port 4 of the first amplitude limiting circuit is connected with the input port ADCA2 of the DSP module; an output port DACA0 of the DSP module is connected with an input port G of a controlled current source, an output port d of the controlled current source is connected with a variable boost inductor L of the main power circuitbThe control end of the controller is connected; an output port EPWM1A of the DSP module is connected with an input port 1 of the isolation drive circuit, an output port 2 of the isolation drive circuit is connected with a boost switching tube Q of the main power circuitbIs connected to the gate of (a).
Further, the DSP module comprises an input voltage sampling algorithm module, an output voltage sampling algorithm module, a first low-pass filtering algorithm module, a second low-pass filtering algorithm module, a first PID algorithm module, a second PID algorithm module, a COMPA calculation algorithm module, an EPWM wave calculation algorithm module, a theoretical duty ratio calculation algorithm module, a variable inductance calculation module, a bias current calculation module and a voltage calculation module; the data input by the ADCA1 enters an input voltage sampling algorithm module, the output of which enters a first low pass filterAn algorithm module; output v of the first low-pass filtering algorithm moduleinEntering a COMPA calculation algorithm module, a theoretical duty ratio calculation algorithm module and a variable inductance calculation module; data input by the ADCA2 enters an output voltage sampling algorithm module, and the output of the output voltage sampling algorithm module enters a second low-pass filtering algorithm module; output V of the second low-pass filter algorithm moduleoEntering a COMPA calculation algorithm module, a theoretical duty ratio calculation algorithm module, a variable inductance calculation module and a first PID algorithm module; output v of the first PID algorithm moduleeaEntering a COMPA calculation algorithm module; output v of COMPA calculation algorithm moduledutyInput EPWM wave calculation algorithm module, output D obtained by EPWM wave calculation algorithm moduley_actAnd the result is output to the second PID algorithm module and the EPWM1A port. Output D of theoretical duty ratio calculation algorithm moduley_refEntering a second PID algorithm module, and outputting v of the second PID algorithm moduleea_LbInputting the variable inductance into a variable inductance calculation module; an output and input value bias current calculation algorithm module of the variable inductance calculation module; the output of the bias current calculation algorithm module is input to the voltage calculation algorithm module; the output value of the voltage calculation algorithm module is output to the DACA0 port.
Boost switching tube Q of DCM Boost PFC converter with variable inductancebThe duty cycle of the on-time of (d) is:
Figure BDA0002650740700000031
wherein D isy_VLBoost switching tube Q for variable inductance controlbDuty ratio of on-time, VmFor input voltage amplitude, VoTo output voltage, ω is the grid angular frequency.
The variable inductance of the boost voltage has the following variation:
Figure BDA0002650740700000032
wherein L isb_VLFor variable boost inductance value, fsSwitching tube for boosting voltageQbSwitching frequency of (P)oIs the output power.
Further, the input voltage sampling circuit comprises a first Hall voltage sensor, a second operational amplifier IC2, a third operational amplifier IC3 and a third resistor R3A fourth resistor R4A fifth resistor R5A sixth resistor R6A seventh resistor R7An eighth resistor R8And a ninth resistor R9And a second resistance C2(ii) a The third resistor R3And an ac input voltage v of the main power circuitinOne end of the first hall voltage sensor 1 is connected, and the other end of the first hall voltage sensor is connected with the positive input end of the first hall voltage sensor 1; the negative input end of the first hall voltage sensor 1 and the alternating input voltage v of the main power circuitinIs directly connected with the other end of the first Hall voltage sensor 1, and the positive output end of the first Hall voltage sensor 1 is connected with the seventh resistor R7Is connected to the forward input terminal of the third operational amplifier IC3, the reverse output terminal of the first hall voltage sensor 1 is connected to the seventh resistor R7The other end of the reference voltage is connected with a reference digital potential zero point; the inverting input terminal of the third operational amplifier IC3 is directly connected to the output terminal thereof, and the output terminal of the third operational amplifier IC3 is connected to the ninth resistor R9Is connected with one end of the connecting rod; ninth resistor R9And the other end of the first resistor is connected with the inverting input terminal of the second operational amplifier IC2 and the sixth resistor R6One end is connected; the positive input terminal of the second operational amplifier IC2 and the fifth resistor R5One terminal and an eighth resistor R8One end of the second operational amplifier IC2 is connected to the output end of the sixth resistor R6The other end and a fourth resistor R4Is connected with one end of the connecting rod; eighth resistor R8The other end is connected with a 5V level; fifth resistor R5With the reference digital potential zero and a second capacitor C2One end is connected; second capacitor C2And the other end of the first resistor and a fourth resistor R4The C terminal of (1) is connected; and the output end C end of the input voltage sampling circuit is connected with the second amplitude limiting circuit.
Further, the output voltage sampling circuit comprises a second Hall voltage sensor, a fourth operational amplifier IC4, a fifth operational amplifier IC5 and a tenth resistor R10The first stepEleven resistors R11And a twelfth resistor R12A thirteenth resistor R13A fourteenth resistor R14A fifteenth resistor R15Sixteenth resistor R16And a third resistor C3(ii) a The sixteenth resistor R16And the output voltage V of the main power circuitoThe other end of the second Hall voltage sensor 2 is connected with the positive input end of the second Hall voltage sensor; the negative input end of the second Hall voltage sensor 2 and the output voltage V of the main power circuitoIs connected with the negative terminal of the second hall voltage sensor 2, and the positive output terminal of the second hall voltage sensor 2 is connected with the fifteenth resistor R15Is connected to the forward input terminal of the fifth operational amplifier IC5, the reverse output terminal of the second hall voltage sensor 2 is connected to the fifteenth resistor R15The other end of the reference voltage is connected with a reference digital potential zero point; the inverting input terminal of the fifth operational amplifier IC5 is directly connected to the output terminal thereof, and the output terminal of the fifth operational amplifier IC5 is connected to the eleventh resistor R11Is connected with one end of the connecting rod; eleventh resistor R11And the other end of the same is connected with the inverting input terminal of the fourth operational amplifier IC4 and the thirteenth resistor R13One end is connected; positive input terminal of fourth operational amplifier IC4 and tenth resistor R10One terminal and a twelfth resistor R12One end of the fourth operational amplifier IC4 is connected to the thirteenth resistor R13The other end and a fourteenth resistor R14Is connected with one end of the connecting rod; a tenth resistor R10The other end is connected with a 5V level; twelfth resistor R12With the reference digital potential zero and a third capacitor C3One end is connected; third capacitor C3And the other end of (1) and a fourteenth resistor R14The end F of (1) is connected; and the output end F end of the output voltage sampling circuit is connected with the first amplitude limiting circuit.
Furthermore, the first amplitude limiting circuit and the second amplitude limiting circuit adopt switching diodes of BAV99 and other models; the first amplitude limiting circuit is connected with an ADCA2 port of the DSP module; the second clipping circuit is connected to the ADCA1 port of the DSP module.
Further, the controlled current source circuit comprises a first operational amplifier IC1, a first resistor R1, a second resistor R2, a first capacitor C1 and a MOS transistor; the first mentionedThe positive input end G of an operational amplifier IC1 is connected with the DACA0 port of the DSP module and one end of a first capacitor, the negative input end of a first operational amplifier IC1 is connected with the s end of a first MOS tube, and the output end of a first operational amplifier IC1 is connected with a first capacitor C1And the other end of the first resistor R1Is connected with one end of the connecting rod; a first resistor R1The other end of the MOS tube is connected with the g end of the MOS tube; the d end of the MOS tube is the output end of the controlled current source, the s end of the MOS tube and the second resistor R2Is connected with one end of the connecting rod; a second resistor R2The other end of the reference voltage is connected with a reference digital potential zero point; controlled current source output end d end and boost switching tube Q of main power circuitbAre connected.
Further, the isolation driving circuit may be a TLP250 type driving chip, and the DSP module may be a DSP28335 or DSP28377 MCU chip; the isolation driving circuit is connected with an EPWM1A port of the DSP module.
Furthermore, the amplifiers used in the first operational amplifier IC1, the second operational amplifier IC2, the third operational amplifier IC3, the fourth operational amplifier IC4 and the fifth operational amplifier IC5 are operational amplifiers of models such as TL074, TL072, LM358 or LM 324.
Compared with the prior art, the invention has the beneficial effects that:
1. compared with the DCM Boost PFC controlled by fixed conduction time, the power factor of the converter is improved;
2. compared with DCM boost PFC controlled by variable conduction time, the invention improves the switching period utilization rate of the converter, and improves the efficiency of the converter;
3. the invention reduces the input current peak value of the converter, reduces the conduction loss of the switch tube and reduces the output voltage ripple.
Drawings
Fig. 1 is a schematic diagram of a main circuit of a DCMBoost PFC converter in an embodiment of the present invention.
Fig. 2 is a waveform diagram of the inductor current and the switching tube of the DCMBoost PFC converter in one switching cycle in an embodiment of the present invention.
Fig. 3 is a schematic diagram of the inductor current in a half power frequency cycle during conventional fixed duty ratio control in the embodiment of the present invention.
Fig. 4 is a graph of the change in PF value of the converter under different controls in an embodiment of the present invention.
Fig. 5 is a graph of the variation of the switching cycle utilization of the converter under different controls in the embodiment of the invention.
Fig. 6 is a diagram illustrating variations of the variable inductor and variations of the inductance according to an embodiment of the present invention.
Fig. 7 is a basic model diagram of a variable inductor according to an embodiment of the present invention.
FIG. 8 shows a variable inductor L according to an embodiment of the present inventionb_VLWith the value of the bias current ibiasThe graph is varied.
Fig. 9 is a diagram of a main circuit and a control circuit of a variable inductance DCMBoost PFC converter according to an embodiment of the present invention.
Fig. 10 is a flow chart of a control algorithm for a variable inductance DCMBoost PFC converter in an embodiment of the present invention.
Fig. 11 is a diagram of the peak envelope of the inductor current for the converter at half power frequency under different control in the embodiment of the present invention.
FIG. 12 is a graph of the input and output power per unit change of the converter under different controls according to the embodiment of the present invention.
Fig. 13 is a graph of the variation of the output voltage ripple of the converter under different controls according to the embodiment of the invention.
Main symbol names in the above figures: v. ofinAnd a power supply voltage. i.e. iinAnd inputting the current. RB, a rectifier bridge. v. ofgAnd the input voltage after the LC filter. i.e. iLbAnd boosting the inductor current. L isbAnd a boost inductor. QbAnd a boost switching tube. DbAnd a boost diode. CoAnd an output capacitor. RLdAnd a load. VoAnd outputting the voltage. v. ofgsAnd a driving signal of the boost switching tube. i.e. iLb_pkAnd boost inductor current peak. i.e. iLbAnd boost inductor current waveform. DyAnd the duty ratio of the conduction time of the boost switching tube. DRAnd the duty ratio of the inductor current falling period time. T issAnd boosting the voltageAnd switching period of the switching tube. i.e. iLb_avgAnd the average value of the boost inductor current. T islineThe period of the input voltage. PF, converter power factor. VrmsAnd an input voltage effective value. ω, input voltage angular frequency. L isb_VLAnd a variable inductance. VmAnd an input voltage amplitude. l1，l3，lgThe auxiliary winding, the main winding and the air gap effective magnetic path length; a. the1，A3The effective sectional areas of the auxiliary magnetic core and the main magnetic core; phibiasThe bias winding current corresponds to the magnetic flux. PhiLbThe main winding current corresponds to the magnetic flux. N is a radical ofL、NCA main induction winding and an auxiliary winding. Mu.s0、μ1、μ3Effective permeability of the main winding air gap, the main winding and the auxiliary winding. i.e. ibiasBias winding current. v. ofeaAnd outputting the error voltage signal of voltage feedback control. Dy_refConverter theoretical duty cycle. Dy_actActual duty cycle of the converter. v. ofea_LbAnd a variable inductance control error signal. v. ofdutyThe converter modulates the wave signal.
Figure BDA0002650740700000061
The instantaneous input power per unit value of the converter.
Figure BDA0002650740700000062
And the fixed duty ratio controls the instantaneous input power per unit value of the converter.
Figure BDA0002650740700000063
And the instantaneous input power per unit value of the variable duty ratio control converter and the variable inductance control converter. ω t1And the electrical angle of the intersection point of the instantaneous input power per unit value and the reference value under the control of the fixed duty ratio. ω t2And the electrical angle of the intersection point of the instantaneous input power per unit value and the reference value under the variable duty ratio control and the variable inductance control. Δ Vo_CDCAnd the ripple value of the output voltage under the control of the fixed duty ratio. Δ Vo_VDC/VLAnd the output voltage ripple value under the variable duty ratio control and the variable inductance control.
Detailed Description
The invention is described in further detail below with reference to the figures and the embodiments.
1DCM boost PFC converter
Working principle of 1.1 variable conduction time control DCM Boost PFC converter
Fig. 1 is a DCM Boost PFC converter main circuit.
Setting: 1. all devices are ideal elements; 2. the output voltage ripple is very small compared to its dc amount; 3. the switching frequency is much higher than the input voltage frequency.
Fig. 2 shows the inductor current waveform during one switching cycle of the converter. When the boost switch tube QbWhen conducting, the boost diode DbCut-off and boost inductor LbThe voltage at both ends is LC filter post-voltage vgCurrent of i thereofLbStarting from zero with vg/LbIs linearly increased, the load RLdFrom an output capacitor CoAnd (5) supplying power. When Q isbAt the time of cut-off, DbConduction, iLbBy DbFollow current, LbVoltage across vg-Vo，iLbWith (v)g-Vo)/LbThe slope of (c) decreases. i.e. iLbAfter dropping to zero, the load RLdFrom an output capacitor CoSupply of power, before the next switching cycle comes iLbRemains at zero.
Without loss of generality, define the input AC voltage vinThe expression of (a) is:
vin＝Vm sinωt (1)
wherein VmAnd ω is the amplitude and angular frequency of the input ac voltage, respectively.
The voltage v rectified by the input voltage and passing through the LC filtergComprises the following steps:
vg＝Vm|sinωt| (2)
by analyzing the working mode of the converter, the peak value i of the boost voltage inductive current can be obtainedLb_pkAverage value of boost inductor current iLb_avgAnd an input current iinExpression (c):
Figure BDA0002650740700000071
Figure BDA0002650740700000072
Figure BDA0002650740700000073
wherein DyIndicating boost switch tube QbDuty ratio, T, corresponding to the on-timesRepresenting the switching period of the converter, DRIndicating boost switch tube QbInductor current i at turn-offLbThe duty cycle corresponding to the fall time.
In each switching cycle, the boost inductor LbBoth ends satisfy the volt-second area balance, then DRAnd iinThe expression of (a) is as follows:
Figure BDA0002650740700000074
Figure BDA0002650740700000075
wherein f issIs the switching frequency of the converter, ands＝1/Ts。
if the converter adopts constant duty ratio control, combining power balance and an equation (7):
Figure BDA0002650740700000076
Figure BDA0002650740700000077
Figure BDA0002650740700000078
in the above formula, Pin_CDCInput power, P, for constant duty ratio control of the converteroFor the converter output power, iin_CDCFor input current in constant duty control, Dy_CDCFor constant duty cycle of the converter, Lb_CDCInductance value, PF, for constant duty cycleCDCIs the PF value in the fixed duty ratio control.
As can be seen from equation (7), the input current of the conventional fixed duty ratio controlled DCM Boost PFC converter is non-sinusoidal, and as shown in fig. 3, the converter PF value is low. The power factor of a conventional fixed duty cycle controlled down-converter can be plotted from equation (10) as shown in fig. 4. From the graph, the power factor of the converter is VmThe increase in (c) is decreasing. When the input voltage is 264VAC and the output voltage is 400V, the PF value is only 0.865.
To raise the theoretical PF value of the DCM Boost PFC converter to 1, combining equation (7), if order:
Figure BDA0002650740700000081
wherein D isy_CDCIs the variable duty cycle of the converter. Input current i of the converter in variable duty cycle controlin_VDCThe expression is as follows:
Figure BDA0002650740700000082
where k is a constant, and the input voltage V of the DCM Boost PFC convertermAn output voltage VoOutput power PoAnd boost inductance value L in variable duty ratio controlb_VDCAnd the like.
Combining power balance and equation (12):
Figure BDA0002650740700000083
Figure BDA0002650740700000084
Figure BDA0002650740700000085
wherein, Pin_VDCThe input power of the converter during the variable duty ratio control is obtained.
As can be seen from equation (15), if the duty cycle of the DCM Boost PFC converter is changed according to equation (11), the input current is sinusoidal and in phase with the input voltage, and the theoretical PF value of the converter is 1, as shown in fig. 4.
Control strategy for achieving high switching cycle utilization
2.1 variable inductance to improve switching cycle utilization
The inductor current of the conventional fixed-duty-ratio control and variable-duty-ratio control DCM Boost PFC converter is still discontinuous. The converter does not transmit energy in the discontinuous stage of the inductive current, and in order to keep constant output power, the peak value of the inductive current is increased, thereby reducing the efficiency of the converter. The proportion of the energy transfer time of the converter (the sum of the rise time and the fall time of the inductance circuit) in the whole switching period is defined as the utilization ratio beta of the switching period:
β＝Dy+DR (16)
according to the expressions (6), (9), (11) and (14), the switching period utilization rate beta of the conventional fixed duty ratio control and variable duty ratio control down converter can be obtainedCDCAnd betaVDCThe following were used:
Figure BDA0002650740700000091
Figure BDA0002650740700000092
as can be seen from equations (17) and (18), the switching period utilization ratio of the converters under the above two controls is always less than 1, and as shown in fig. 5, the efficiency of the DCM Boost PFC converter still has a room for improvement.
As can be seen from the equation (18), if the inductance L is variableb_VLCan be changed within a half power frequency period according to the following formula (19):
Figure BDA0002650740700000093
the switching cycle utilization of the converter is then betaVLDuty ratio Dy_VLAnd an input current iin_VLThe expression of (a) is as follows:
βVL＝1 (20)
Figure BDA0002650740700000094
Figure BDA0002650740700000095
fig. 6 shows the variation of the variable inductance and the corresponding inductance value in the wide voltage range of 90V to 264VAC according to the equation (19). It can be seen from fig. 6 that when the input voltage has an effective value of 90VAC, the control inductance varies regularly within the range of 0.222mH-0.322 mH; when the voltage effective value is 110VAC, the inductance is controlled to change within the range of 0.308mH-0.504mH according to a certain rule; when the voltage effective value is input to 176VAC, the inductance is controlled to change within the range of 0.488mH-1.291mH according to a certain rule; when the voltage effective value is input to 220VAC, the inductance is controlled to change within the range of 0.448mH-2.017mH according to a certain rule; when the voltage effective value 264VAC is input, the control inductance is changed within the range of 0.193mH-2.904mH according to a certain rule, and the constant utilization rate of the switching period under a wide voltage range can be ensured to be 1. The new control not only keeps the advantage that the unit power factor can be realized by the variable duty ratio control, but also realizes the constancy of the utilization rate of the switching period through the variable inductance technology, reduces the peak value of the inductance current and improves the overall performance of the converter.
The basic model of variable inductance is shown in FIG. 7, and is composed of two side auxiliary windings and a middle main winding, and the auxiliary windings N are controlled to flow throughCBias current i ofbiasCan change the inductance L of the main magnetic corebIn the present invention, a double E-type core is used, as shown in fig. 7. Main induction winding NLWound on a central core with an air gap, and an auxiliary winding wound on NCOn both sides of the core, two auxiliary windings are connected in series to eliminate the current i from the main inductorLbInduced voltage due to ripple. When no bias current exists, the main winding maintains the initial inductance value which is the same as the normal inductance; when there is a bias current ibiasFlows through NCThen, a bias flux phi is generated along the external path of the double E-shaped magnetic corebiasWith phibiasIncreasing the working point of the external path magnetic core on the B-H curve from a linear region to a nonlinear saturation region, reducing the magnetic permeability of the path magnetic core, and generating main magnetic flux phi when the main winding is electrifiedLbDue to main magnetic flux phiLbThe main inductance is also affected by the bias current flowing through the middle core and the external path. In summary, ibiasThe effective permeability on the external path core is reduced, resulting in a main inductance Lb_VLAnd decreases.
According to the basic model of variable inductance in fig. 8, the calculation formula of the main inductance can be derived as follows:
Figure BDA0002650740700000101
in the formula I1，l3，lgThe lengths of the auxiliary winding, the main winding and the air gap effective magnetic circuit are respectively; a. the1，A3Is the effective sectional area of the auxiliary magnetic core and the main magnetic core; n is3Is the number of turns of the main winding; mu.s0Is the air permeability; mu.s3And muvarThe effective permeability of the main and auxiliary windings respectively.
As can be seen from equation (23), the variable inductance is substantially a change in μ by the bias currentvarI.e. effective magnetic coupling with the auxiliary windingAnd (4) conductivity. A variable inductance model is built in simulation software LTSPICE, and variable inductance L is drawnb_VLWith the value of the bias current ibiasThe variation is shown in fig. 8.
2.2 control Circuit
For the DCM Boost PFC converter with high efficiency and high PF value of the variable inductor, the continuous variable inductor is used for realizing that the utilization rate of a switching period in a half power frequency period is 1. Therefore, the actual switching period utilization rate obtained by the actual duty ratio operation can be compared with the target value and error adjustment is performed, and the obtained variable inductance adjustment error signal, the input voltage, the output voltage and the like are sent to the variable inductance calculation module. According to the relationship between the bias current and the required inductance value obtained in fig. 8, the bias current required to reach the corresponding inductance value can be calculated, and then the constant current source module generates the direct current passing through the variable inductance bias winding.
According to the equations (19) and (21), a control circuit diagram shown in fig. 9 and an algorithm flowchart shown in fig. 10 can be designed. Inputting an input voltage signal acquired by ADCA1 and an output voltage signal acquired by ADCA2 into a DSP module, and obtaining an input voltage v by the input voltage signal through an input voltage sampling algorithm module and a first low-pass filtering algorithm moduleinA value of (d); the output voltage signal passes through an output voltage sampling algorithm module and a second low-pass filtering algorithm module to obtain an output voltage VoThe error signal v of the voltage closed loop is obtained through a first PID algorithm moduleeaWill error signal veaAnd an input voltage vinDirectly used for the calculation of a COMPA algorithm module; and inputting the COMPA obtained by the COMPA algorithm module into the EPWM wave calculation algorithm module, and finally obtaining the EPWMA by the EPWM wave calculation algorithm module, so that the duty ratio of the DCM Boost PFC converter is controlled to change in a form of a formula (21).
Using input voltage vinAnd an output voltage VoThe theoretical duty ratio D of the converter can be calculatedy_refWill be the theoretical duty cycle Dy_refD output by EPWM wave calculation algorithm moduley_actObtaining a variable inductance regulation error signal v through a second PID algorithm moduleea_LbThe signal andinput voltage vinAn output voltage VoThe input value bias current calculation algorithm module is used for the variable inductance calculation module and the input value bias current calculation algorithm module for calculation of the variable inductance calculation module; the output of the bias current calculation algorithm module is input to the voltage calculation algorithm module; the output value of the voltage calculation algorithm module is output to the DACA0 port. Thereby controlling the variable inductance value of the DCM Boost PFC converter to vary in the form of equation (19).
With reference to fig. 9 and 10, the variable-inductance high-efficiency high-PF-value DCM Boost PFC converter includes a main power circuit including an input voltage source v and a control circuitinEMI filter, rectifying circuit RB, LC filter, variable boost inductor LbBoost switching tube QbAnd a boost diode DbAn output capacitor CoAnd a load RLd(ii) a The control circuit comprises an input voltage sampling circuit, an output voltage sampling circuit, a first amplitude limiting circuit, a second amplitude limiting circuit, a DSP module, an isolation driving circuit and a controlled current source circuit;
the main power circuit is respectively connected with the input voltage sampling circuit, the output voltage sampling circuit, the controlled current source circuit and the isolation driving circuit; the input voltage sampling circuit is connected with the first amplitude limiting circuit; the output voltage sampling circuit is connected with the second amplitude limiting circuit; the DSP module is respectively connected with the first amplitude limiting circuit, the second amplitude limiting circuit, the controlled source circuit and the isolation driving circuit;
the ADC submodule of the DSP module collects input voltage and output voltage data, performs related algorithm processing, the EPWM submodule outputs a driving signal of a switching tube, and the DAC submodule outputs a voltage signal required by controlling the variable inductor.
Further, the input voltage source vinThe output port of the EMI filter is connected with the input port of a rectifier bridge RB, the output positive port of the rectifier bridge RB is connected with the input positive port of the LC filter, the output negative port of the rectifier bridge RB is connected with the input negative port of the LC filter, the output positive port of the LC filter is connected with a variable boost inductor LbIs connected to the output of the LC filterNegative outlet and boost switch tube QbSource electrode and output capacitor CoNegative terminal of and load RLdIs connected with the negative terminal of the LC filter, the negative port of the LC filter is a reference potential zero point, and the variable boost inductor LbAnd the other end of the diode D and a boost diode DbPositive terminal and boost switching tube QbIs connected to the drain of the variable boost inductor LbThe control end of the voltage boosting switch tube Q is connected with a controlled current source circuitbThe grid of the grid is connected with the isolation driving circuit; boost diode DbNegative terminal of and output capacitor CoAnd a load RLdIs connected to the positive terminal of the load RLdThe voltage at both ends is output voltage Vo(ii) a Load RLdBoth ends of the output voltage sampling circuit are connected with the output voltage sampling circuit.
Furthermore, the positive input end of the input voltage sampling circuit passes through a current limiting resistor R3AC input voltage v to main power circuitinIs connected with the reverse input end of the input voltage sampling circuit and is directly connected with the alternating current input voltage v of the main power circuitinThe output port C of the input voltage sampling circuit is connected with the input port 1 of the second amplitude limiting circuit, and the output port 2 of the second amplitude limiting circuit is connected with the input port ADCA1 of the DSP module; the positive input end of the output voltage sampling circuit passes through a current limiting resistor R16With the output voltage V of the main power circuitoIs connected with the positive port of the main power circuit, and the reverse input end of the output voltage sampling circuit is directly connected with the output voltage V of the main power circuitoThe output port F of the output voltage sampling circuit is connected with the input port 3 of the first amplitude limiting circuit, and the output port 4 of the first amplitude limiting circuit is connected with the input port ADCA2 of the DSP module; an output port DACA0 of the DSP module is connected with an input port G of a controlled current source, an output port d of the controlled current source is connected with a variable boost inductor L of the main power circuitbThe control end of the controller is connected; an output port EPWM1A of the DSP module is connected with an input port 1 of the isolation drive circuit, an output port 2 of the isolation drive circuit is connected with a boost switching tube Q of the main power circuitbIs connected to the gate of (a).
Further, the DSP module comprises an input voltage sampling calculationThe device comprises a method module, an output voltage sampling algorithm module, a first low-pass filtering algorithm module, a second low-pass filtering algorithm module, a first PID algorithm module, a second PID algorithm module, a COMPA calculation algorithm module, an EPWM wave calculation algorithm module, a theoretical duty ratio calculation algorithm module, a variable inductance calculation module, a bias current calculation module and a voltage calculation module; the data input by the ADCA1 enters an input voltage sampling algorithm module, and the output of the ADCA1 enters a first low-pass filtering algorithm module; output v of the first low-pass filtering algorithm moduleinEntering a COMPA calculation algorithm module, a theoretical duty ratio calculation algorithm module and a variable inductance calculation module; data input by the ADCA2 enters an output voltage sampling algorithm module, and the output of the output voltage sampling algorithm module enters a second low-pass filtering algorithm module; output V of the second low-pass filter algorithm moduleoEntering a COMPA calculation algorithm module, a theoretical duty ratio calculation algorithm module, a variable inductance calculation module and a first PID algorithm module; output v of the first PID algorithm moduleeaEntering a COMPA calculation algorithm module; output v of COMPA calculation algorithm moduledutyInput EPWM wave calculation algorithm module, output D obtained by EPWM wave calculation algorithm moduley_actAnd the result is output to the second PID algorithm module and the EPWM1A port. Output D of theoretical duty ratio calculation algorithm moduley_refEntering a second PID algorithm module, and outputting v of the second PID algorithm moduleea_LbInputting the variable inductance into a variable inductance calculation module; an output and input value bias current calculation algorithm module of the variable inductance calculation module; the output of the bias current calculation algorithm module is input to the voltage calculation algorithm module; the output value of the voltage calculation algorithm module is output to the DACA0 port.
Boost switching tube Q of DCM Boost PFC converter with variable inductancebThe duty cycle of the on-time of (d) is:
Figure BDA0002650740700000131
wherein D isy_VLBoost switching tube Q for variable inductance controlbDuty ratio of on-time, VmFor input voltage amplitude, VoTo output voltage, ω is the grid angular frequency.
The variable inductance of the boost voltage has the following variation:
Figure BDA0002650740700000132
wherein L isb_VLFor variable boost inductance value, fsFor step-up switching tube QbSwitching frequency of (P)oIs the output power.
Further, the input voltage sampling circuit comprises a first Hall voltage sensor, a second operational amplifier IC2, a third operational amplifier IC3 and a third resistor R3A fourth resistor R4A fifth resistor R5A sixth resistor R6A seventh resistor R7An eighth resistor R8And a ninth resistor R9And a second resistance C2(ii) a The third resistor R3And an ac input voltage v of the main power circuitinOne end of the first hall voltage sensor 1 is connected, and the other end of the first hall voltage sensor is connected with the positive input end of the first hall voltage sensor 1; the negative input end of the first hall voltage sensor 1 and the alternating input voltage v of the main power circuitinIs directly connected with the other end of the first Hall voltage sensor 1, and the positive output end of the first Hall voltage sensor 1 is connected with the seventh resistor R7Is connected to the forward input terminal of the third operational amplifier IC3, the reverse output terminal of the first hall voltage sensor 1 is connected to the seventh resistor R7The other end of the reference voltage is connected with a reference digital potential zero point; the inverting input terminal of the third operational amplifier IC3 is directly connected to the output terminal thereof, and the output terminal of the third operational amplifier IC3 is connected to the ninth resistor R9Is connected with one end of the connecting rod; ninth resistor R9And the other end of the first resistor is connected with the inverting input terminal of the second operational amplifier IC2 and the sixth resistor R6One end is connected; the positive input terminal of the second operational amplifier IC2 and the fifth resistor R5One terminal and an eighth resistor R8One end of the second operational amplifier IC2 is connected to the output end of the sixth resistor R6The other end and a fourth resistor R4Is connected with one end of the connecting rod; eighth resistor R8The other end is connected with a 5V level; fifth resistor R5Another end of (1)With reference digital potential zero and a second capacitor C2One end is connected; second capacitor C2And the other end of the first resistor and a fourth resistor R4The C terminal of (1) is connected; and the output end C end of the input voltage sampling circuit is connected with the second amplitude limiting circuit.
Further, the output voltage sampling circuit comprises a second Hall voltage sensor, a fourth operational amplifier IC4, a fifth operational amplifier IC5 and a tenth resistor R10An eleventh resistor R11And a twelfth resistor R12A thirteenth resistor R13A fourteenth resistor R14A fifteenth resistor R15Sixteenth resistor R16And a third resistor C3(ii) a The sixteenth resistor R16And the output voltage V of the main power circuitoThe other end of the second Hall voltage sensor 2 is connected with the positive input end of the second Hall voltage sensor; the negative input end of the second Hall voltage sensor 2 and the output voltage V of the main power circuitoIs connected with the negative terminal of the second hall voltage sensor 2, and the positive output terminal of the second hall voltage sensor 2 is connected with the fifteenth resistor R15Is connected to the forward input terminal of the fifth operational amplifier IC5, the reverse output terminal of the second hall voltage sensor 2 is connected to the fifteenth resistor R15The other end of the reference voltage is connected with a reference digital potential zero point; the inverting input terminal of the fifth operational amplifier IC5 is directly connected to the output terminal thereof, and the output terminal of the fifth operational amplifier IC5 is connected to the eleventh resistor R11Is connected with one end of the connecting rod; eleventh resistor R11And the other end of the same is connected with the inverting input terminal of the fourth operational amplifier IC4 and the thirteenth resistor R13One end is connected; positive input terminal of fourth operational amplifier IC4 and tenth resistor R10One terminal and a twelfth resistor R12One end of the fourth operational amplifier IC4 is connected to the thirteenth resistor R13The other end and a fourteenth resistor R14Is connected with one end of the connecting rod; a tenth resistor R10The other end is connected with a 5V level; twelfth resistor R12With the reference digital potential zero and a third capacitor C3One end is connected; third capacitor C3And the other end of (1) and a fourteenth resistor R14The end F of (1) is connected; the output end F end of the output voltage sampling circuit is connected with the first amplitude limiting circuit。
Furthermore, the first amplitude limiting circuit and the second amplitude limiting circuit adopt switching diodes of BAV99 and other models; the first amplitude limiting circuit is connected with an ADCA2 port of the DSP module; the second clipping circuit is connected to the ADCA1 port of the DSP module.
Further, the controlled current source circuit comprises a first operational amplifier IC1, a first resistor R1, a second resistor R2, a first capacitor C1 and a MOS transistor; the positive input end G of the first operational amplifier IC1 is connected with a DACA0 port of the DSP module and one end of a first capacitor, the negative input end of the first operational amplifier IC1 is connected with the s end of a first MOS tube, and the output end of the first operational amplifier IC1 is connected with the first capacitor C1And the other end of the first resistor R1Is connected with one end of the connecting rod; a first resistor R1The other end of the MOS tube is connected with the g end of the MOS tube; the d end of the MOS tube is the output end of the controlled current source, the s end of the MOS tube and the second resistor R2Is connected with one end of the connecting rod; a second resistor R2The other end of the reference voltage is connected with a reference digital potential zero point; controlled current source output end d end and boost switching tube Q of main power circuitbAre connected.
Further, the isolation driving circuit may be a TLP250 type driving chip, and the DSP module may be a DSP28335 or DSP28377 MCU chip; the isolation driving circuit is connected with an EPWM1A port of the DSP module.
Furthermore, the amplifiers used in the first operational amplifier IC1, the second operational amplifier IC2, the third operational amplifier IC3, the fourth operational amplifier IC4 and the fifth operational amplifier IC5 are operational amplifiers of models such as TL074, TL072, LM358 or LM 324.
3 advantages of novel control
3.1 improvement of Power factor
According to the equations (7), (10), (15) and (22), PF curves of the variable-inductance DCM Boost PFC converter under the conventional constant duty control, variable duty control and variable-inductance control can be plotted, as shown in fig. 4. As can be seen from the figure, the theoretical PF value of the converter under the control of the variable inductor is 1 in a wide input voltage range of 90V-264 VAC, and when high voltage is input, the PF value is greatly improved compared with the traditional constant duty ratio control mode, and the PF value improving effect is obvious.
3.2 switching cycle utilization improvement
According to the design parameters of the converter: input voltage vin: 90V to 264 VAC; output voltage Vo: 400V; output power Po: 120W; switching frequency f of the converters: 100 kHz; output capacitor C of converter o220 muF; the critical inductance value L of the traditional down converter with constant duty ratio control and variable duty ratio control can be respectively calculatedb_CDC: 80 μ H and Lb_VDC：180μH。
According to the formula (17), the formula (18) and the formula (20), the variation curve of the switching period utilization rate of the DCM Boost PFC converter in a half power frequency period under different controls is combined with the parameters of the converter, as shown in fig. 6. As can be seen in fig. 6: 1) the switching period is constant in the power frequency period and is no longer a function changing along with the omega t, and the utilization rate of the switching period in the power frequency period is successfully increased to 1. 2) Compared with the traditional fixed duty ratio control and variable duty ratio control, the switching period utilization rate of the DCM Boost PFC converter controlled by the variable inductor is obviously improved.
3.3 inductor Current Peak reduction
According to the formula (3), the formula (9), the formula (11), the formula (14) and the formula (21), the inductance current peak value i of the DCM Boost PFC converter under the traditional constant duty ratio control, variable conduction time control and variable inductance control can be obtainedLb_pk_CDC、iLb_pk_VDCAnd iLb_pk_VL：
Figure BDA0002650740700000151
Figure BDA0002650740700000152
Figure BDA0002650740700000153
The change of the peak envelope amplitude of the inductor current of the DCM Boost PFC converter under three kinds of control along with the effective value of the input voltage can be drawn according to the formula, and the change is shown in figure 11. As can be seen from fig. 11, the peak value of the inductor current of the DCM Boost PFC converter under the control of the variable inductor is smaller than those of the other two controls, which further causes the current stress of the device to be reduced, the loss of the converter to be reduced, and the efficiency of the converter to be improved.
3.4 reduction of output Voltage ripple
When the fixed duty ratio control is adopted, the instantaneous input power per unit value of the converter can be obtained by the formulas (1), (7) and (9)
Figure BDA0002650740700000161
(the reference value is the output power) is:
Figure BDA0002650740700000162
the input current of the converter is in a sine form by adopting variable duty ratio control and variable inductance control. The instantaneous input power per unit value of the converter can be obtained from the equations (1), (15) and (22)
Figure BDA0002650740700000163
(the reference value is the output power):
Figure BDA0002650740700000164
the change curves of the instantaneous input power per unit value in the half power frequency period under three different control modes can be drawn by the equations (27) and (28), as shown in fig. 12.
When in use
Figure BDA0002650740700000165
Time, energy storage capacitor CoCharging; when in use
Figure BDA0002650740700000166
When, CoAnd (4) discharging. Two controls are performedIn the mode, the output capacitor CoThe per unit maximum energy values (the reference value is the output energy in the half power frequency period) stored in the half power frequency period are respectively as follows:
Figure BDA0002650740700000167
Figure BDA0002650740700000168
according to the calculation formula of the capacitance energy storage,
Figure BDA0002650740700000169
and
Figure BDA00026507407000001610
can be expressed as:
Figure BDA00026507407000001611
Figure BDA00026507407000001612
wherein Δ Vo_CDCAnd Δ Vo_VDC/VLThe voltage ripple values are output for a constant duty cycle and a variable duty cycle (variable inductance control), respectively.
The output voltage ripples obtained from equations (30a) and (30b) are:
Figure BDA00026507407000001613
Figure BDA0002650740700000171
fig. 13 is drawn from equation (31), and it can be seen that, after the variable inductance control is adopted, when the input voltage is 90VAC, the output voltage ripple is reduced to 93.9% of the original value, when the input voltage is 110VAC, the output voltage ripple is reduced to 91.4% of the original value, when the input voltage is 220VAC, the output voltage ripple is reduced to 75.5% of the original value, and when the input voltage is 264VAC, the output voltage ripple is reduced to 65.3% of the original value.
Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that various changes in the embodiments and modifications of the invention can be made, and equivalents and modifications of some features of the invention can be made without departing from the spirit and scope of the invention.

Claims (10)

1. The invention discloses a high-efficiency high-PF-value DCM Boost PFC converter with variable inductance, which comprises a main power circuit and a control circuit, wherein the main power circuit comprises an input voltage source vinEMI filter, rectifying circuit RB, LC filter, variable boost inductor LbBoost switching tube QbAnd a boost diode DbAn output capacitor CoAnd a load RLd(ii) a The control circuit comprises an input voltage sampling circuit, an output voltage sampling circuit, a first amplitude limiting circuit, a second amplitude limiting circuit, a DSP module, an isolation driving circuit and a controlled current source circuit;
the main power circuit is respectively connected with the input voltage sampling circuit, the output voltage sampling circuit, the controlled current source circuit and the isolation driving circuit; the input voltage sampling circuit is connected with the first amplitude limiting circuit; the output voltage sampling circuit is connected with the second amplitude limiting circuit; the DSP module is respectively connected with the first amplitude limiting circuit, the second amplitude limiting circuit, the controlled source circuit and the isolation driving circuit;
the ADC submodule of the DSP module collects input voltage and output voltage data, performs related algorithm processing, the EPWM submodule outputs a driving signal of a switching tube, and the DAC submodule outputs a voltage signal required by controlling the variable inductor.
2. According to the claimsThe DCM Boost PFC converter with high efficiency and high PF value for solving 1 of the variable inductor is characterized in that an input voltage source vinThe output port of the EMI filter is connected with the input port of a rectifier bridge RB, the output positive port of the rectifier bridge RB is connected with the input positive port of the LC filter, the output negative port of the rectifier bridge RB is connected with the input negative port of the LC filter, the output positive port of the LC filter is connected with a variable boost inductor LbIs connected with the output negative port of the LC filter and the boost switching tube QbSource electrode and output capacitor CoNegative terminal of and load RLdIs connected with the negative terminal of the LC filter, the negative port of the LC filter is a reference potential zero point, and the variable boost inductor LbAnd the other end of the diode D and a boost diode DbPositive terminal and boost switching tube QbIs connected to the drain of the variable boost inductor LbThe control end of the voltage boosting switch tube Q is connected with a controlled current source circuitbThe grid of the grid is connected with the isolation driving circuit; boost diode DbNegative terminal of and output capacitor CoAnd a load RLdIs connected to the positive terminal of the load RLdThe voltage at both ends is output voltage Vo(ii) a Load RLdBoth ends of the output voltage sampling circuit are connected with the output voltage sampling circuit.
3. The DCM Boost PFC converter with high efficiency and high PF value and according to claim 1, wherein a forward input end of the input voltage sampling circuit passes through a current limiting resistor R3AC input voltage v to main power circuitinIs connected with the reverse input end of the input voltage sampling circuit and is directly connected with the alternating current input voltage v of the main power circuitinThe output port C of the input voltage sampling circuit is connected with the input port 1 of the second amplitude limiting circuit, and the output port 2 of the second amplitude limiting circuit is connected with the input port ADCA1 of the DSP module; the positive input end of the output voltage sampling circuit passes through a current limiting resistor R16With the output voltage V of the main power circuitoThe reverse input end of the output voltage sampling circuit is directly connected with the output voltage of the main power circuitVoThe output port F of the output voltage sampling circuit is connected with the input port 3 of the first amplitude limiting circuit, and the output port 4 of the first amplitude limiting circuit is connected with the input port ADCA2 of the DSP module; an output port DACA0 of the DSP module is connected with an input port G of a controlled current source, an output port d of the controlled current source is connected with a variable boost inductor L of the main power circuitbThe control end of the controller is connected; an output port EPWM1A of the DSP module is connected with an input port 1 of the isolation drive circuit, an output port 2 of the isolation drive circuit is connected with a boost switching tube Q of the main power circuitbIs connected to the gate of (a).
4. The DCM Boost PFC converter with high efficiency and high PF value for the variable inductor according to claim 1, wherein the DSP module comprises an input voltage sampling algorithm module, an output voltage sampling algorithm module, a first low pass filtering algorithm module, a second low pass filtering algorithm module, a first PID (proportion, integral, differential link) algorithm module, a second PID algorithm module, a COMPA (modulated wave) calculation algorithm module, an EPWM wave calculation algorithm module, a theoretical duty cycle calculation algorithm module, a variable inductor calculation module, a bias current calculation module and a voltage calculation module; the data input by the ADCA1 enters an input voltage sampling algorithm module, and the output of the ADCA1 enters a first low-pass filtering algorithm module; output v of the first low-pass filtering algorithm moduleinEntering a COMPA calculation algorithm module, a theoretical duty ratio calculation algorithm module and a variable inductance calculation module; data input by the ADCA2 enters an output voltage sampling algorithm module, and the output of the output voltage sampling algorithm module enters a second low-pass filtering algorithm module; output V of the second low-pass filter algorithm moduleoEntering a COMPA calculation algorithm module, a theoretical duty ratio calculation algorithm module, a variable inductance calculation module and a first PID algorithm module; output v of the first PID algorithm moduleeaEntering a COMPA calculation algorithm module; output v of COMPA calculation algorithm moduledutyInput EPWM wave calculation algorithm module, output D obtained by EPWM wave calculation algorithm moduley_actAnd the result is output to the second PID algorithm module and the EPWM1A port. Output D of theoretical duty ratio calculation algorithm moduley_refInto a second PIDAlgorithm module, output v of second PID algorithm moduleea_LbInputting the variable inductance into a variable inductance calculation module; an output and input value bias current calculation algorithm module of the variable inductance calculation module; the output of the bias current calculation algorithm module is input to the voltage calculation algorithm module; the output value of the voltage calculation algorithm module is output to the DACA0 port.
Boost switching tube Q of DCM Boost PFC converter with variable inductorbThe duty cycle of the on-time of (d) is:
Figure FDA0002650740690000021
wherein D isy_VLBoost switching tube Q for variable inductance controlbDuty ratio of on-time, VmFor input voltage amplitude, VoTo output voltage, ω is the grid angular frequency.
The variable boost inductor has the following variation form:
Figure FDA0002650740690000022
wherein L isb_VLFor variable boost inductance value, fsFor step-up switching tube QbSwitching frequency of (P)oIs the output power.
5. The variable-inductance, high-efficiency, high-PF-value DCM Boost PFC converter of claim 3, wherein the input voltage sampling circuit comprises a first Hall voltage sensor, a second operational amplifier IC2, a third operational amplifier IC3, a third resistor R3A fourth resistor R4A fifth resistor R5A sixth resistor R6A seventh resistor R7An eighth resistor R8And a ninth resistor R9And a second resistance C2(ii) a The third resistor R3And an ac input voltage v of the main power circuitinIs connected with one end of the first Hall voltage sensor 1, and the other end is connected with the forward input of the first Hall voltage sensor 1The input end is connected; the negative input end of the first hall voltage sensor 1 and the alternating input voltage v of the main power circuitinIs directly connected with the other end of the first Hall voltage sensor 1, and the positive output end of the first Hall voltage sensor 1 is connected with the seventh resistor R7Is connected to the forward input terminal of the third operational amplifier IC3, the reverse output terminal of the first hall voltage sensor 1 is connected to the seventh resistor R7The other end of the reference voltage is connected with a reference digital potential zero point; the inverting input terminal of the third operational amplifier IC3 is directly connected to the output terminal thereof, and the output terminal of the third operational amplifier IC3 is connected to the ninth resistor R9Is connected with one end of the connecting rod; ninth resistor R9And the other end of the first resistor is connected with the inverting input terminal of the second operational amplifier IC2 and the sixth resistor R6One end is connected; the positive input terminal of the second operational amplifier IC2 and the fifth resistor R5One terminal and an eighth resistor R8One end of the second operational amplifier IC2 is connected to the output end of the sixth resistor R6The other end and a fourth resistor R4Is connected with one end of the connecting rod; eighth resistor R8The other end is connected with a 5V level; fifth resistor R5With the reference digital potential zero and a second capacitor C2One end is connected; second capacitor C2And the other end of the first resistor and a fourth resistor R4The C terminal of (1) is connected; and the output end C end of the input voltage sampling circuit is connected with the second amplitude limiting circuit.
6. The DCM Boost PFC converter with high efficiency and PF value and variable inductance of claim 3, wherein the output voltage sampling circuit comprises a second Hall voltage sensor, a fourth operational amplifier IC4, a fifth operational amplifier IC5, a tenth resistor R10An eleventh resistor R11And a twelfth resistor R12A thirteenth resistor R13A fourteenth resistor R14A fifteenth resistor R15Sixteenth resistor R16And a third resistor C3(ii) a The sixteenth resistor R16And the output voltage V of the main power circuitoThe other end of the second Hall voltage sensor 2 is connected with the positive input end of the second Hall voltage sensor; the negative input end of the second Hall voltage sensor 2 and the output voltage V of the main power circuitoIs connected with the negative terminal of the second hall voltage sensor 2, and the positive output terminal of the second hall voltage sensor 2 is connected with the fifteenth resistor R15Is connected to the forward input terminal of the fifth operational amplifier IC5, the reverse output terminal of the second hall voltage sensor 2 is connected to the fifteenth resistor R15The other end of the reference voltage is connected with a reference digital potential zero point; the inverting input terminal of the fifth operational amplifier IC5 is directly connected to the output terminal thereof, and the output terminal of the fifth operational amplifier IC5 is connected to the eleventh resistor R11Is connected with one end of the connecting rod; eleventh resistor R11And the other end of the same is connected with the inverting input terminal of the fourth operational amplifier IC4 and the thirteenth resistor R13One end is connected; positive input terminal of fourth operational amplifier IC4 and tenth resistor R10One terminal and a twelfth resistor R12One end of the fourth operational amplifier IC4 is connected to the thirteenth resistor R13The other end and a fourteenth resistor R14Is connected with one end of the connecting rod; a tenth resistor R10The other end is connected with a 5V level; twelfth resistor R12With the reference digital potential zero and a third capacitor C3One end is connected; third capacitor C3And the other end of (1) and a fourteenth resistor R14The end F of (1) is connected; and the output end F end of the output voltage sampling circuit is connected with the first amplitude limiting circuit.
7. The DCM Boost PFC converter with high efficiency and high PF value and the variable inductance as claimed in claim 3, wherein the first and second clipping circuits are switching diodes of BAV99 type; the first amplitude limiting circuit is connected with an ADCA2 port of the DSP module; the second clipping circuit is connected to the ADCA1 port of the DSP module.
8. The DCM Boost PFC converter with high efficiency and high PF value and according to claim 3, wherein the controlled current source circuit comprises a first operational amplifier IC1, a first resistor R1, a second resistor R2, a first capacitor C1 and a MOS transistor; the positive input end G of the first operational amplifier IC1 is connected with the DACA0 port of the DSP module and one end of the first capacitor, the negative input end of the first operational amplifier IC1 is connected with the s end of the first MOS tube, and the positive input end of the first operational amplifier IC1 is connected with the S end of the first MOS tubeOutput terminal and first capacitor C1And the other end of the first resistor R1Is connected with one end of the connecting rod; a first resistor R1The other end of the MOS tube is connected with the g end of the MOS tube; the d end of the MOS tube is the output end of the controlled current source, the s end of the MOS tube and the second resistor R2Is connected with one end of the connecting rod; a second resistor R2The other end of the reference voltage is connected with a reference digital potential zero point; controlled current source output end d end and boost switching tube Q of main power circuitbAre connected.
9. The DCM Boost PFC converter with high efficiency and high PF value and the variable inductor according to claim 3, wherein the isolation driving circuit can be a TLP250 type driving chip, and the DSP module can be a DSP28335 or DSP28377 type MCU chip; the isolation driving circuit is connected with an EPWM1A port of the DSP module.
10. The DCM Boost PFC converter with high efficiency and PF value and variable inductance as claimed in claim 3, wherein the amplifiers used in the first operational amplifier IC1, the second operational amplifier IC2, the third operational amplifier IC3, the fourth operational amplifier IC4 and the fifth operational amplifier IC5 are TL074, TL072, LM358 or LM324 operational amplifiers.
CN202010869908.1A 2020-08-26 2020-08-26 High Efficiency and High PF Value DCM Boost PFC Converter with Variable Inductance Pending CN112217387A (en)

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Publication number Priority date Publication date Assignee Title
CN112886812A (en) * 2021-02-05 2021-06-01 广东工业大学 Dynamic adjusting method and device of DC-DC converter
CN114362564A (en) * 2021-08-23 2022-04-15 南京理工大学 DCM boost converter with high efficiency of unit power factor and adopting segmented variable inductance
CN114362564B (en) * 2021-08-23 2024-04-02 南京理工大学 Unit power factor high efficiency DCM boost converter employing segmented varistors
CN114096042A (en) * 2021-10-26 2022-02-25 武汉理工大学 A multi-channel constant current output LED driving power supply based on variable boost inductance
CN114583791A (en) * 2022-03-17 2022-06-03 威睿电动汽车技术(宁波)有限公司 Charging control method, device and system and storage medium
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