CN101615899B - Nonlinear pulse width modulation control device of single-phase current source grid-connected inverter - Google Patents

Abstract

The invention relates to a nonlinear pulse width modulation control device of a single-phase current source grid-connected inverter. The device can be used for adjusting duty ratio in time and outputting high quality power grid current by feedback of modulation current, so as to effectively overcome the native defect of serious aberration of power grid current wave form when the traditional linear PWM control strategy is adopted; a control circuit of the device comprises an integrating circuit having high frequency resetting function, an absolute-value circuit I, a comparison circuit, a RS trigger, a combinational logic circuit as well as a reference sinusoidal current circuit, an absolute-value circuit II, a zero-crossing comparison circuit and a constant frequency clock circuit that have fixed phase relationship with the power grid voltage. The nonlinear pulse width modulation control device can lead unstable DC voltage to be converted into stable grid-connected current with the needed magnitude and high quality, and has the advantages of single stage power conversion, high conversion efficiency, small harmonic wave of the grid-connected current, rapid dynamic response, high reliability when in overloading, low cost and the like, so as to establish key technology for a renewable energy source grid-connected power generation system.

Description

The non-linear impulse-width modulation control device of monophase current source grid-connected inverter

Technical field

The non-linear impulse-width modulation control device of a kind of monophase current source grid-connected inverter involved in the present invention belongs to power electronic technology.

Background technology

Because fossil energy (non-renewable energy resources) growing tensions such as oil, coal and natural gas, environmental pollution are serious, global warming, nuclear energy production can produce reasons such as nuke rubbish and contaminated environment, the energy and environment have become the significant problem that the 21 century mankind are faced.Regenerative resources (green energy resource) such as solar energy, wind energy, tidal energy and geothermal energy, have cleanliness without any pollution, cheapness, advantage such as reliable, abundant, the development and utilization regenerative resource more and more is subject to people's attention, and this has considerable meaning to the countries in the world sustainable development of economy.

The direct current energy of renewable energy conversion such as solar energy, wind energy, Hydrogen Energy, tidal energy, geothermal energy is normally unsettled, it need be reverse into AC energy and electrical network generates electricity by way of merging two or more grid systems.Therefore, the parallel network reverse technology has vital status in the development and utilization field of new forms of energy.

At present, combining inverter mainly adopts voltage-type (Buck type) combining inverter.Must satisfy the peak value of dc voltage during the circuit structure operate as normal of this class inverter greater than AC side voltage, so have an obvious defects: when dc voltage (as the photovoltaic cell fan-out capability) reduces, as overcast and rainy or night, the whole generating system is with out of service, and the utilance of system descends.To this, the method that often adopts prime to add the Boost converter solves this problem, from and increased complexity, loss and the cost of circuit.Therefore, Buck type combining inverter has defectives such as circuit structure complexity, multistage Power Conversion, conversion efficiency are low, cost height.

Current mode (Boost type) combining inverter belongs to single-stage booster type grid-connected inverting system, thereby becomes a research focus in generation of electricity by new energy field.Compare with voltage-type (Buck type) grid-connected inverting system, current mode (Boost type) grid-connected inverting system has following characteristics: dc voltage must be higher than the line voltage peak value and keep constant during the work of (1) voltage source inverter, the inadequate work of system will cause the power network current harmonic content big when direct voltage is low, prime is added the Boost converter scheme of boosting, will increase system cost and reduce conversion efficiency, and current source inverter can be controlled input DC side electric current by the overlapping conducting time of two power switchs on the same brachium pontis of control inverter, and it is succinct to have a circuit structure, single-stage power conversion, the conversion efficiency height, cost is low, can realize during the photovoltaic inversion can be to advantages such as high light energy overall process utilizations from the low light level; (2) current source inverter is the direct control to output current, realize that the control of energy MPPT maximum power point tracking is more convenient reliable, and voltage source inverter realizes that MPPT maximum power point tracking causes the collapse of dc bus easily and reduces reliability when controlling; (3) energy-storage travelling wave tube of current source inverter is an inductance, and lifetime of system will be that the voltage source inverter of electrochemical capacitor is long than energy-storage travelling wave tube; (4) protected the reliability height of system easily timely when current mode grid-connected inverting system generation overcurrent and short circuit.

In recent years, along with the appearance of new devices such as two-way IGBT capable of blocking, the no longer essential series diode of current source inverter has solved the loss problem of series diode.By the inductance of appropriate design current source inverter DC side, also can effectively solve the efficiency of this class inverter energy storage inductor.Therefore, the current mode combining inverter has important theory and engineering using value.

Single-phase electricity flow pattern combining inverter circuit topology and input thereof and output voltage principle waveform are as shown in Figure 1, 2.Single-phase electricity flow pattern combining inverter is at HF switch on off state equivalent electric circuit during DTs and (1-D) Ts in the cycle, shown in Fig. 3,4.Heavy line shown in Fig. 3,4 in the equivalent electric circuit is illustrated in the path of current flowing during this period.From Fig. 2,3,4 as can be known, in a power frequency output cycle, t ₁-t ₂, t ₃-t ₄During this time (| u _N|＞U _i) any one HF switch all exist inductance L to magnetize the stage (during the DTs) in the cycle and dispel the magnetic stage (during (1-D) Ts), satisfy the basic principle of Boost code converter, be transported to the current waveform i of electrical network _LfThe quality height; At t ₀-t ₁, t ₂-t ₃, t ₄-t ₅During this time (| u _N|＜U _i) any one HF switch be magnetize the stage (during the Ts) of inductance L in the cycle, do not have and dispel the magnetic stage, do not satisfy the basic principle of Boost code converter, be transported to the current waveform i of electrical network _LfDistortion is serious.

Control block diagram and principle waveform when the single phase boost type combining inverter adopts conventional linear PWM control strategy are shown in Fig. 5,6.Among Fig. 6, θ is benchmark sinusoidal current i _rBe ahead of line voltage u _nPhase place.With power network current feedback signal i _LfWith benchmark sinusoidal current signal i _rRelatively, behind proportional integral amplifying circuit and absolute value circuit again with sawtooth carrier wave i _cHand over to cut and generate high-frequency PWM signal i _Hf, the benchmark sinusoidal current signal i of fixed phase relationship is arranged with line voltage _rBehind zero-crossing comparator, obtain gating signal i _Sy, gating signal i _SyAnd inversion signal Behind drive circuit, be used for the power controlling switch S ₁, S ₂, i _HfWith

Behind XOR gate, drive circuit, be used for the power controlling switch S ₃, i _HfWith Behind XOR gate, not gate, drive circuit, be used for the power controlling switch S ₄Because the duty ratio D and the error current signal (i of inverter _r-i _Lf) be directly proportional, so this control strategy is called the Linear Control strategy.Can find out the power network current i of this class inverter significantly from Fig. 6 _LfThere is the severe distortion phenomenon, at the error current i of an output cycle memory in a plurality of cycles _e, i _HfWith power switch S ₃, S ₄Control signal be irregular high-frequency PWM signal (non-SPWM signal).Therefore, there is obvious defects in the single phase boost type combining inverter when adopting conventional linear PWM control strategy, is difficult to apply in engineering.

Therefore, seek that a kind of effectively to solve the serious Distortion Control strategy of output power network current waveform that exists when the single phase boost type combining inverter adopts conventional P WM control strategy extremely urgent, for effective improvement output power network current waveform quality, improve utilization rate of electrical, reduce electromagnetic interference, bring into play this topological potential, widen power electronics parallel network reverse technology and renewable energy power generation technology, promote that development, the development of renewable energy power generation industry is energy-saving all to have great importance with conservation-minded society.

Summary of the invention

The present invention seeks to provide a kind of non-linear impulse-width modulation control device by the monophase current source grid-connected inverter of reliability advantages of higher when having power density height, single-stage power conversion, conversion efficiency height, load overload and short circuit.

Technical program of the present invention lies in: a kind of non-linear impulse-width modulation control device of monophase current source grid-connected inverter, be by the integrating circuit that contains the high frequency reset function, the absolute value circuit I, comparison circuit, rest-set flip-flop, combinational logic circuit, with line voltage the benchmark sinusoidal current ' s circuit of fixed phase relationship is arranged, the absolute value circuit II, the zero passage comparison circuit, the constant frequency clock circuit constitutes, the described integrating circuit input that contains the high frequency reset function is connected with the modulated current feedback end, the integrating circuit output that contains the high frequency reset function is connected with the input of absolute value circuit I, the output of absolute value circuit I is connected with an input of comparison circuit, the output of comparison circuit is connected with the reset terminal of rest-set flip-flop, the output Q of rest-set flip-flop is connected the output of rest-set flip-flop with an input of combinational logic circuit

With resetting in the integrating circuit that contains the high frequency reset function

The control end of switch is connected, another input of described comparison circuit is connected with the output of absolute value circuit II, the input of absolute value circuit II with have the output of the benchmark sinusoidal current ' s circuit of fixed phase relationship to be connected with line voltage, described have the output of the benchmark sinusoidal current ' s circuit of fixed phase relationship also to be connected with the input of zero passage comparison circuit with line voltage, the output of zero passage comparison circuit is connected with another input of combinational logic circuit, the set end of described rest-set flip-flop is connected with the output of constant frequency clock circuit, four outputs of described combinational logic circuit and the input of four drive circuits connect one to one, the significant level state of the reset terminal of rest-set flip-flop and set end, the input phase state of comparison circuit and zero passage comparison circuit, the concrete form of combinational logic circuit should be able to satisfy the needed logic level relation of monophase current source grid-connected inverter operate as normal.

The present invention will " the monophase current source grid-connected inverter be by feedback power network current i _LfWith benchmark sinusoidal current i _rCompare, hand over carrier wave again through the proportional integral amplifying circuit and cut a conventional linear control device that generates pwm signal ", be configured to " by feedback and real-time quadrature modulates current i _m, with benchmark sinusoidal current i _rRelatively, generate the nonlinear Control device of pwm signal again by rest-set flip-flop "; proposed non-linear pulse width modulation controlled new ideas of monophase current source grid-connected inverter and control device; promptly in time adjust the duty ratio and the outputting high quality power network current of inverter, overcome the serious distortion phenomenon that the power network current waveform existed when the monophase current source grid-connected inverter adopted conventional linear PWM control strategy effectively by the modulated current of detection and feedback phase current source grid-connected inverter.

The invention has the advantages that: the present invention can become unsettled dc voltage conversion required size, stable, high-quality grid-connected current, have that circuit topology is succinct, single-stage power conversion, power density height, conversion efficiency height, the grid-connected current harmonic wave is little, dynamic response fast, reliability height when load overload and short circuit, lifetime of system is longer than voltage source inverter, cost is low, be specially adapted to advantages such as the omnidistance light-use of photovoltaic parallel in system and MPPT maximum power point tracking control, for the regenerative resource grid-connected system has been established key technology.

Description of drawings

Fig. 1. single-phase electricity flow pattern combining inverter circuit topology.

Fig. 2. input of single-phase electricity flow pattern combining inverter and output voltage principle waveform.

Fig. 3. the on off state equivalent electric circuit during the single-phase electricity flow pattern combining inverter DTs.

Fig. 4. the on off state equivalent electric circuit during single-phase electricity flow pattern combining inverter (1-D) Ts.

Fig. 5. the conventional linear PWM control device theory diagram of single-phase electricity flow pattern combining inverter.

Fig. 6. the conventional linear PWM control principle waveform of single-phase electricity flow pattern combining inverter.

Fig. 7. the nonlinear PWM control device theory diagram of single-phase electricity flow pattern combining inverter.

Fig. 8. the nonlinear PWM control principle waveform when the upper and lower brachium pontis of single-phase electricity flow pattern combining inverter is respectively low frequency, HF switch.

Fig. 9. the nonlinear PWM control principle waveform when the left and right brachium pontis of single-phase electricity flow pattern combining inverter is half cycle low frequency, half cycle HF switch.

Figure 10. set end and reset terminal that the nonlinear PWM control device circuit block diagram example one of single-phase electricity flow pattern combining inverter---upper and lower brachium pontis is respectively low frequency, HF switch and rest-set flip-flop are that high level is effective.

Figure 11. set end and reset terminal that the nonlinear PWM control device example circuit diagram one of single-phase electricity flow pattern combining inverter---upper and lower brachium pontis is respectively low frequency, HF switch and rest-set flip-flop are that high level is effective.

Figure 12. set end and reset terminal that the nonlinear PWM control device circuit block diagram example two of single-phase electricity flow pattern combining inverter---upper and lower brachium pontis is respectively low frequency, HF switch and rest-set flip-flop are that low level is effective.

Figure 13. set end and reset terminal that the nonlinear PWM control device example circuit diagram two of single-phase electricity flow pattern combining inverter---upper and lower brachium pontis is respectively low frequency, HF switch and rest-set flip-flop are that low level is effective.

Figure 14. set end and reset terminal that the nonlinear PWM control device circuit block diagram example three of single-phase electricity flow pattern combining inverter---left and right brachium pontis is half cycle low frequency, half cycle HF switch and rest-set flip-flop are that high level is effective.

Figure 15. set end and reset terminal that the nonlinear PWM control device example circuit diagram three of single-phase electricity flow pattern combining inverter---left and right brachium pontis is half cycle low frequency, half cycle HF switch and rest-set flip-flop are that high level is effective.

Embodiment

Below in conjunction with drawings and Examples the present invention is described further.

The non-linear pulse width modulation controlled of monophase current source grid-connected inverter is by detecting the also modulated current i of feedback phase current source grid-connected inverter _mIn time adjust the duty ratio of inverter and the power network current of outputting high quality, power network current i when overcoming this inverter effectively and adopting conventional linear PWM control strategy _LfThe inherent shortcoming that has serious distortion.Control principle waveform when control principle waveform and left and right brachium pontis were half cycle low frequency, half cycle HF switch when the nonlinear PWM control principle block diagram of single-phase electricity flow pattern combining inverter and upper and lower brachium pontis thereof were respectively low frequency, HF switch is respectively shown in Fig. 7,8,9.The modulated current feedback signal i of single-phase electricity flow pattern combining inverter _MfObtain current average signal i behind the integrating circuit through containing the high frequency reset function _Avg, i _AvgAfter the absolute value circuit I, obtain | i _Avg|, | i _Avg| the benchmark sinusoidal current signal i of fixed phase relationship is arranged with line voltage together _rThe reference current absolute value signal that after the absolute value circuit II, obtains | i _r| comparing has obtained high-frequency PWM signal i _Hf, i _HfWith constant frequency clock signal i _cRespectively as the reset terminal and the set end of rest-set flip-flop, the output of rest-set flip-flop

As the high frequency integration reset signal (being the control signal of reset switch) of integrating circuit, i _rThrough the polarity gating signal i that obtains behind the zero balancing circuit _SyBehind suitable combinational logic circuit, drive circuit, be used for the power controlling switch S respectively with the output Q of rest-set flip-flop ₁, S ₂, S ₃, S ₄

The character of monophase current source grid-connected inverter circuit topology will cause modulated current i _mAt t shown in Figure 2 ₀-t ₁, t ₂-t ₃, t ₄-t ₅Value during this time (| u _N|＜U _i) greater than desired value, modulated current i _mThe time that reaches fiducial value through the integrator integration will shorten, thereby just can effectively reduce the duty ratio of inverter in a high frequency period, thereby effectively improve output power network current waveform quality.Therefore, the non-linear impulse-width modulation control device of monophase current source grid-connected inverter is by detecting the also modulated current i of feedback phase current source grid-connected inverter _mIn time adjust the duty ratio of inverter and the power network current of outputting high quality, power network current i when having overcome this inverter effectively and adopting conventional linear PWM control device _LfThe inherent shortcoming that has serious distortion.Obviously, each HF switch cycle reset of integrating circuit once, the frequency of high frequency integration reset signal equals the HF switch frequency of inverter.

The duty ratio of supposing inverter is D, HF switch period T _s, then the inverter inductive energy storage, release can during be respectively DT _s, (1-D) T _s, combining inverter modulated current feedback signal i _MfThe signal i that behind integrating circuit, obtains _AvgAnd absolute value signal | i _Avg| be respectively

$i_{\mathrm{avg}}=-\frac{1}{T_s}{\∫}_0^{(1-D)T_s}{i}_{\mathrm{mf}}\mathrm{dt}---\left(1\right)$

$\left|i_{\mathrm{avg}}\right|=\left|\frac{1}{T_s}{\∫}_0^{(1-D)T_s}{i}_{\mathrm{mf}}\mathrm{dt}\right|---\left(2\right)$

Formula (1), (2) show i _Avg, | i _Avg| be respectively modulated current feedback signal i _MfAnd absolute value signal | i _Avg| mean value.Because HF switch period T _sMuch smaller than the line voltage cycle, output filter capacitor C _fTerminal voltage and power network current i _LfAt a T _sIn can regard approximately constant as, thereby at a T _sInterior output filter capacitor C _fIn average value current be approximately zero, can be according to Kirchhoff's current law (KCL) at a T _sInterior power network current i _LfWith combining inverter modulated current signal i _mMean value equate, promptly

$i_{\mathrm{Lf}}=\frac{1}{T_S}{\∫}_0^{(1-D)T_S}{i}_m\mathrm{dt}---\left(3\right)$

Formula (1), (2) (3) show, if combining inverter modulated current feedback factor is 1, and modulated current signal i then _mWith its feedback signal i _MfEquate, at a T _sInterior power network current i _LfEqual i _AvgThe benchmark sinusoidal current signal i that therefore, fixed phase relationship is arranged by control and line voltage _rJust can effectively control power network current i _LfWhen input voltage or load variations, by regulating reference voltage i _rChange duty ratio D, just can realize the stable and adjusting of the output current (power output) of combining inverter, this is a basic demand of combining inverter just.Because modulated current feedback signal i _MfAt a T _sIn can regard approximately constant as, then

$\left|i_{\mathrm{avg}}\right|=\left|\frac{1}{T_s}{\∫}_0^{(1-D)T_s}{i}_{\mathrm{mf}}\mathrm{dt}\right|$

$=\left|\frac{1}{T_S}{i}_{\mathrm{mf}}{\∫}_0^{(1-D)T_S}\mathrm{dt}\right|$

$=\left|i_{\mathrm{mf}}(1-D)\right|$

$={\left|i_r\right|}_{t=(1-D)T_s}---\left(4\right)$

Can get by (4),

$1-D=\left|\frac{i_r}{i_{\mathrm{mf}}}\right|---\left(5\right)$

Formula (5) shows, 1-D only with

Be directly proportional, not with error current | i _r-i _Mf| be directly proportional, so this control strategy is called non-linear pulse width modulation controlled strategy.The output voltage U of monophase current source grid-connected inverter _nWith input direct voltage U _i, the pass between the duty ratio D is U _n=U _i/ (1-D).Because so 0＜D＜1 is U _nU _o＞U _i, i.e. output dc voltage U _nAlways be higher than input direct voltage U _iSo, this converter is called the booster type combining inverter.

In this nonlinear PWM control device theory diagram, the reset terminal of rest-set flip-flop and set end both can be that high level can be that low level is effective effectively, also, comparison circuit and zero passage comparison circuit both can be homophase inputs, also can be anti-phase input that the form of combinational logic circuit was varied especially.The input phase state of the significant level state of the reset terminal of rest-set flip-flop and set end, comparison circuit and zero passage comparison circuit, the concrete form of combinational logic circuit should be able to satisfy the needed logic level relation of monophase current source grid-connected inverter operate as normal, promptly will satisfy the upper and lower brachium pontis of inverter shown in Figure 8 and be operated in two kinds of typical nonlinear PWM control device principle waveforms that low frequency, HF switch and the left and right brachium pontis of inverter shown in Figure 9 all are operated in half cycle low frequency, half cycle HF switch respectively.

High-frequency inverter is with the dither half-sinusoid direct current i among the energy storage inductor L _LBe reverse into the modulated current i of unipolarity binary states _m, through output filter capacitor C _f, output inductor L _fAfter obtain high-quality power network current waveform i _LfThis current mode combining inverter can only be from the input power supply to the load transfer energy, and load can not occur to input power supply feedback energy.

The non-linear impulse-width modulation control device of monophase current source grid-connected inverter of the present invention is by feedback and real-time quadrature modulates current i _m, with benchmark sinusoidal current i _rRelatively, generate pwm signal by rest-set flip-flop again, with by feedback power network current i _LfWith benchmark sinusoidal current i _rRelatively, hand over the conventional linear impulse-width modulation control device that cuts the generation pwm signal to have important difference with carrier wave again through the proportional integral amplifying circuit.Therefore, control device of the present invention is creative, have that the power network current harmonic wave is little, control circuit is succinct, dynamic corresponding speed is fast and reliability height when system changeover efficient height (meaning that energy loss is little), power density height (mean volume, weight little), load overload and short circuit, advantage such as cost is low, application prospect is extensive, has more important value the today of building energy-saving, economizing type and environment-friendly type society vigorously advocating.

Non-linear impulse-width modulation control device circuit block diagram of monophase current source grid-connected inverter and circuit embodiments are shown in Figure 10,11,12,13,14,15.It is effective control device circuit block diagram of high level and control device circuit that Figure 10,11 is respectively set end and the reset terminal that upper and lower brachium pontis is respectively low frequency, HF switch and rest-set flip-flop.In the control device circuit block diagram shown in Figure 10, modulated current mean value absolute value signal | i _Avg| and the absolute value signal of the benchmark sinusoidal current of fixed phase relationship is arranged with line voltage | i _r|, difference is homophase, the rp input signal of device as a comparison; With line voltage the benchmark sinusoidal current signal i of fixed phase relationship is arranged _rWith the zero level signal, respectively as homophase, the rp input signal of zero-crossing comparator; High-frequency PWM signal i _HfWith constant frequency clock signal i _c, respectively as the reset terminal R and the set end S of rest-set flip-flop; Combinational logic circuit is made of two not gates and a NOR gate circuit, the output Q of rest-set flip-flop and polarity gating signal i _SyTwo input signals as combinational logic circuit.In the control device circuit diagram shown in Figure 11, integrating circuit is by resistance R ₁, R ₂, capacitor C ₁, high frequency reset switch S and amplifier IC1 constitute, absolute value circuit I is by resistance R ₃, R ₄, R ₅, R ₉, R ₁₀, diode D ₁, D ₂, D ₃, D ₄With amplifier IC ₂, IC ₃Constitute, absolute value circuit II is by resistance R ₆, R ₇, R ₈, R ₁₁, R ₁₂, diode D ₅, D ₆, D ₇, D ₈With amplifier IC ₄, IC ₅Constitute IC ₆Be comparator circuit, IC ₇Be the effective rest-set flip-flop of input high level, IC ₈Be the zero-crossing comparator circuit, combinational logic circuit is by not gate IC ₉, IC ₁₁With XOR gate IC ₁₀Constitute.

It is effective control device circuit block diagram of low level and control circuit that Figure 12,13 is respectively set end and the reset terminal that upper and lower brachium pontis is respectively low frequency, HF switch and rest-set flip-flop.In the control device circuit block diagram shown in Figure 12, modulated current mean value absolute value signal | i _Avg| and the absolute value signal of the benchmark sinusoidal current of fixed phase relationship is arranged with line voltage | i _r|, difference is anti-phase, the in-phase input signals for 1 of device as a comparison; With line voltage the benchmark sinusoidal current signal i of fixed phase relationship is arranged _rWith the zero level signal, respectively as homophase, the rp input signal of zero-crossing comparator; High-frequency PWM signal i _HfWith constant frequency clock signal i _c, respectively as the reset terminal of rest-set flip-flop

With the set end

Combinational logic circuit is by two not gates and an XOR

Gate circuit constitutes, the output Q of rest-set flip-flop and polarity gating signal i _SyTwo input signals as combinational logic circuit.

In the control device circuit diagram shown in Figure 13, integrating circuit is by resistance R ₁, R ₂, capacitor C ₁, high frequency reset switch S and amplifier IC1 constitute, absolute value circuit I is by resistance R ₃, R ₄, R ₅, R ₉, R ₁₀, diode D ₁, D ₂, D ₃, D ₄With amplifier IC ₂, IC ₃Constitute, absolute value circuit II is by resistance R ₆, R ₇, R ₈, R ₁₁, R ₁₂, diode D ₅, D ₆, D ₇, D ₈With amplifier IC ₄, IC ₅Constitute IC ₆Be comparator circuit, IC ₇Be the effective rest-set flip-flop of input low level, IC ₈Be the zero-crossing comparator circuit, combinational logic circuit is by not gate IC ₉, IC ₁₁With XOR gate IC ₁₀Constitute.

It is effective control device circuit block diagram of high level and control circuit that Figure 14,15 is respectively set end and the reset terminal that left and right brachium pontis is half cycle low frequency, half cycle HF switch and rest-set flip-flop.In the control device circuit block diagram shown in Figure 14, modulated current mean value absolute value signal | i _Avg| and the absolute value signal of the benchmark sinusoidal current of fixed phase relationship is arranged with line voltage | i _r|, difference is homophase, the rp input signal of device as a comparison; With line voltage the benchmark sinusoidal current signal i of fixed phase relationship is arranged _rWith the zero level signal, respectively as homophase, the rp input signal of zero-crossing comparator; High-frequency PWM signal i _HfWith constant frequency clock signal i _c, respectively as the reset terminal R and the set end S of rest-set flip-flop; Combinational logic circuit is made of four not gates and two OR circuit, the output Q of rest-set flip-flop,

With polarity gating signal i _SyThree input signals as combinational logic circuit.In the control device circuit diagram shown in Figure 15, integrating circuit is by resistance R ₁, R ₂, capacitor C ₁, high frequency reset switch S and amplifier IC1 constitute, absolute value circuit I is by resistance R ₃, R ₄, R ₅, R ₉, R ₁₀, diode D ₁, D ₂, D ₃, D ₄With amplifier IC ₂, IC ₃Constitute, absolute value circuit II is by resistance R ₆, R ₇, R ₈, R ₁₁, R ₁₂, diode D ₅, D ₆, D ₇, D ₈With amplifier IC ₄, IC ₅Constitute IC ₆Be comparator circuit, IC ₇Be the effective rest-set flip-flop of input high level, IC ₈Be the zero-crossing comparator circuit, combinational logic circuit is by not gate IC ₉, IC ₁₀, IC ₁₂, IC ₁₄With or the door IC ₁₁, IC ₁₃Constitute.

Non-linear pulse width modulation controlled single-phase electricity flow pattern combining inverter, be applicable to unsettled dc voltage conversion is become required size, stable, high-quality grid-connected current, has single-stage power conversion, the conversion efficiency height, the grid-connected current harmonic wave is little, dynamic response is fast, reliability height during the load overload, low cost and other advantages, can be used to realize to have the combining inverter in the regenerative resource power supply system of premium properties and wide application prospect, as photovoltaic cell 40-60VDC/220V50HzAC, 10kw Proton Exchange Membrane Fuel Cells 85-120V/220V50HzAC, middle-size and small-size family wind power generation 24-36-48VDC/220V50HzAC etc.

Claims (1)

1. the non-linear impulse-width modulation control device of a monophase current source grid-connected inverter, it is characterized in that: this control device is by the integrating circuit that contains the high frequency reset function, the absolute value circuit I, comparison circuit, rest-set flip-flop, combinational logic circuit, with line voltage the benchmark sinusoidal current ' s circuit of fixed phase relationship is arranged, the absolute value circuit II, the zero passage comparison circuit, the constant frequency clock circuit constitutes, the described integrating circuit input that contains the high frequency reset function is connected with the modulated current feedback end, the integrating circuit output that contains the high frequency reset function is connected with the input of absolute value circuit I, the output of absolute value circuit I is connected with an input of comparison circuit, the output of comparison circuit is connected with the reset terminal of rest-set flip-flop, the output Q of rest-set flip-flop is connected the output of rest-set flip-flop with an input of combinational logic circuit

Be connected with the control end of reset switch in the integrating circuit that contains the high frequency reset function, another input of described comparison circuit is connected with the output of absolute value circuit II, the input of absolute value circuit II with have the output of the benchmark sinusoidal current ' s circuit of fixed phase relationship to be connected with line voltage, described have the output of the benchmark sinusoidal current ' s circuit of fixed phase relationship also to be connected with the input of zero passage comparison circuit with line voltage, the output of zero passage comparison circuit is connected with another input of combinational logic circuit, the set end of described rest-set flip-flop is connected with the output of constant frequency clock circuit, four outputs of described combinational logic circuit and the input of four drive circuits connect one to one, the significant level state of the reset terminal of rest-set flip-flop and set end, the input phase state of comparison circuit and zero passage comparison circuit, the concrete form of combinational logic circuit should be able to satisfy the needed logic level relation of monophase current source grid-connected inverter operate as normal.

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