CN203827207U - Three-phase PWM rectifier system with improved space vector control - Google Patents

Abstract

The utility model discloses a three-phase PWM rectifier system with improved space vector control, belonging to the field of power electronic converter technology and intelligent control. The rectifier system of the utility model comprises a three-phase PWM rectifier power main circuit, a voltage detection circuit, a current detection circuit, a synchronous voltage circuit, a buffer circuit and a DSP processor. The three-phase PWM rectifier system has the advantages of simple circuit structure, the realization of fixed frequency control of a switch tube, input power factor as 1, low net side current harmonic distortion rate, fast dynamic response, strong anti-interference ability, simple circuit design, stable DC output, simple control algorithm and easy realization of digitization.

Description

The three-phase PWM commutation system of modified model space vector control

Technical field

The utility model relates to three phase rectifier technology, especially relates to the three-phase PWM commutation system of modified model space vector control.

Background technology

Along with the development of power electronic technology, countries in the world generally start to pay close attention to efficient, the free of contamination electric energy problem of utilizing.And current domestic heavy-duty rectifier generally adopts not controlling and controlled rectifier of diode and thyristor realization, its current waveform distorts and injects a large amount of harmonic waves and reactive power to electrical network, causes serious electric network pollution.

Three-phase PWM Voltage Rectifier has the plurality of advantages such as ac-side current harmonic wave is low, power factor is high, direct voltage output is stable, becomes one of hot subject of current power electronic applications research.Now widely used control strategy is as follows: stagnant chain rate, triangle SPWM control, vector control and Feedforward Decoupling.But these control methods have shortcoming separately: stagnant ring control cannot realize fixed-frequency control, brings difficulty to circuit design; Triangle SPWM controls needs higher switching frequency just can reach low harmonic requirement; Although but the harmonic wave of the lower generation of vector control switching frequency is larger; And for Feedforward Decoupling, when model is inaccurate or when system parameters and model parameter Incomplete matching, the vector control based on rotating coordinate transformation still exist decoupling zero control failure may, affect the control performance of system.

Utility model content

For the shortcoming of existing control strategy, the utility model object is to provide the three-phase PWM commutation system of modified model space vector control.Adopt various control strategy in conjunction with control, realize the fixed-frequency control of switching tube, simplify circuit design, when improving circuit reliability, improve input power factor and reduce ac-side current harmonic wave.

The purpose of this utility model can be achieved through the following technical solutions:

The three-phase PWM commutation system of modified model space vector control, comprise: three-phase PWM rectified power main circuit, voltage detecting circuit, current detection circuit, synchronizing voltage circuit and for Three-Phase PWM Rectifier being carried out to the dsp processor of modified model space vector control, three-phase PWM rectified power main circuit respectively with voltage detecting circuit, current detection circuit, the input of synchronizing voltage circuit connects, voltage detecting circuit, current detection circuit, the output of synchronizing voltage circuit is connected with dsp processor, the output of dsp processor connects the driving input of six switching tubes of three-phase PWM rectified power main circuit.

Described three-phase PWM rectified power main circuit comprises: three-phase alternating-current supply, three-phase reactor, three-phase commutation bridge, buffer circuit, electric capacity and load, and three phase rectifier module has adopted six Switch Three-Phase half bridge circuit topologys, realizes AC and converts to DC; Described voltage detecting circuit adopts Hall voltage transducer to detect the three-phase commutation bridge output voltage of AC three-phase alternating voltage (three phase network voltage) and three-phase PWM rectified power main circuit; Described current detection circuit sampling Hall current sensor detects AC three-phase alternating current, i.e. three phase network input current; Described synchronizing voltage circuit adopts phase lock circuitry to calculate the locking phase of three phase network voltage.

Described buffer circuit is composed in parallel by current-limiting resistance and relay, reduces ac-side current amplitude in conducting moment.

Described dsp processor adopts Texas Instruments's 2000 series DSP controllers.

Compared with prior art, the beneficial effects of the utility model are:

This practical information adopts three-phase PWM rectified power main circuit, voltage detecting circuit, current detection circuit, synchronizing voltage circuit, buffer circuit and dsp processor, simplify circuit design, under identical switching frequency, circuit harmonizing wave is less, realize unity power factor operation, little to electric network pollution, control simply, be easy to Digital Realization.

Brief description of the drawings

Fig. 1 is the Three-Phase PWM Rectifier system configuration schematic diagram of a kind of modified model space vector of the present utility model control;

Fig. 2 is the Three-Phase PWM Rectifier control method schematic diagram of a kind of modified model space vector of the present utility model control;

Fig. 3 is application matlab simulated effect figure of the present utility model.

Embodiment

As shown in Figure 1, the Three-Phase PWM Rectifier system of a kind of modified model space vector of the present utility model control, comprise: three-phase PWM rectified power main circuit 1, voltage detecting circuit, current detection circuit, synchronizing voltage circuit and for Three-Phase PWM Rectifier being carried out to the dsp processor of modified model space vector control, three-phase PWM rectified power main circuit 1 respectively with voltage detecting circuit, current detection circuit, the input of synchronizing voltage circuit connects, voltage detecting circuit, current detection circuit, the output of synchronizing voltage circuit is connected with dsp processor, the output of dsp processor connects the driving input of six switching tubes of three-phase PWM rectified power main circuit 1.Three-phase PWM rectified power main circuit 1 comprises: three-phase alternating-current supply E, three-phase reactor L, three-phase commutation bridge K, buffer circuit 2, capacitor C and load RL, and three phase rectifier module has adopted six Switch Three-Phase half bridge circuit topologys, realizes AC and converts to DC; ; It is the voltage at load two ends that outer voltage PI controls Vdc in 3, and Vdc* is the reference voltage of three-phase commutation bridge output; It is three-phase alternating current instruction current that trigonometric ratio is controlled is* in 4, and is is three-phase alternating current actual current;

As shown in Figure 2, Three-Phase PWM Rectifier control method of the present utility model, key step comprises: (S1) current detection circuit sampling ac-side current, voltage detecting circuit sampling AC voltage and three-phase commutation bridge output voltage signal, the phase place of synchronizing voltage circuit synchronous AC side three-phase alternating voltage simultaneously, dsp processor calculates according to the output of phase lock circuitry the ac voltage signal that three amplitudes are 1, and respectively with the three-phase alternating voltage same-phase of AC; Dsp processor utilizes the three-phase commutation bridge output voltage that obtains of step (S1) sampling to carry out outer voltage PI adjusting 3; (S3) dsp processor utilizes the outer voltage PI of ac voltage signal that three amplitudes that step (S1) obtains are 1 and step (S2) to regulate result to carry out triangle wave Current Control 4; (S4) dsp processor carries out stagnant ring control 5 according to the result of triangle wave Current Control; (S5) dsp processor carries out space vector control (6) according to the result of stagnant ring control 5.

In step (S1), to obtain three-phase commutation bridge output voltage signal, three-phase alternating current signal and electric network voltage phase signal by Hall voltage transducer, Hall current sensor and phase lock circuitry, three-phase commutation bridge output voltage signal, three-phase alternating current signal that dsp processor obtains sampling are converted to digital signal, simultaneously obtain according to the electric network voltage phase calculated signals of the output of phase lock circuitry the ac voltage signal that three amplitudes are 1, and these three amplitudes ac voltage signal that is 1 respectively with the three-phase alternating voltage same-phase of AC.

In step (S2), the three-phase commutation bridge output voltage that dsp processor will be realized three-phase PWM commutation system is as with reference to voltage, deduct with reference to voltage the three-phase commutation bridge output voltage that sampling obtains, and using the poor input regulating as PI, realize outer voltage PI and regulate 3.

In step (S3), to regulate the result of (3) as the amplitude of instruction current signal outer voltage PI, the amplitude of instruction current signal is multiplied each other and obtains three instruction current signals with above-mentioned three amplitudes that calculate ac voltage signal that is 1 respectively, again that three instruction current signals are poor with current on line side signal respectively, and using the poor input as triangle comparison controller, after regulating, frequently determines with fixing again PI, the triangular wave of fixed amplitude is made comparisons, completing trigonometric ratio controls, this control can realize switching frequency and fix, control simple, fast response time.

In step (S4), be that the result of triangle wave Current Control (4) is input to the comparator with hysteresis characteristic.In the time that the absolute value of input value is greater than given ring width H, the output switching activity of hysteresis comparator; In the time that the absolute value of input value is less than ring width H, the output of hysteresis comparator is constant, and this control response is fast, and harmonic wave is little, switching loss is low.

In step (S5), be by 6 road signals of stagnant ring control (5) output by space vector control (6), implementation space vector control, refers to Fig. 1, ignores rectifier AC resistance, obtains according to Kirchhoff's second law:

$L\frac{\mathrm{dI}}{\mathrm{dt}}=E-V---\left(1\right)$

Wherein: E is three phase network electromotive force vector, V is AC three-phase alternating voltage vector, and I is AC three-phase alternating current flow vector, and t is the time.

I* is AC three-phase alternating current instruction current vector, and error current vector is

ΔI＝I*-I （2）

By formula (2) substitution formula (1),

$L\frac{\mathrm{d\ΔI}}{\mathrm{dt}}=V-E+L\frac{\mathrm{dI}*}{\mathrm{dt}}---\left(3\right)$

From formula (3), be 0 if will make error current vector, i.e. zero error current response, the reference voltage vector V* of three-phase commutation bridge output should meet

$V*=E-L\frac{\mathrm{dI}*}{\mathrm{dt}}---\left(4\right)$

For Three-phase PWM Voltage Rectifier, the limited combination of 6 switching tubes can produce 8 space voltage vector V _k(k=0 ..., 7), substitution formula (3)

$L\frac{\mathrm{d\ΔI}}{\mathrm{dt}}=V_k-E+L\frac{\mathrm{dI}*}{\mathrm{dt}},(k=0,...,7)---\left(5\right)$

By formula (4) substitution formula (5),

$L\frac{\mathrm{d\ΔI}}{\mathrm{dt}}=V_k-V*,(k=0,...,7)---\left(6\right)$

From formula (6), can select suitable space voltage vector V _k(k=0 ..., 7) departure current phasor interconversion rate, make error current vector Δ I as far as possible little, according to space voltage vector V _krequirement adjust 6 road PWM output waveforms, thereby realize High Power Factor, low harmonic wave, low-loss three-phase PWM rectification, this control has the average frequency of switching that precision is high, response is fast, reduce largely device simultaneously, reduces switching loss.

If Fig. 3 is for application matlab simulated effect figure of the present utility model, in figure, can find out that current on line side followed the tracks of voltage on line side well, both phase places are identical, and are all sinusoidal wave.In addition, in the time that load increases suddenly, current on line side still can be followed the tracks of voltage on line side well.

Those skilled in the art can make various amendments to this specific embodiment or supplement or adopt similar mode to substitute under the prerequisite without prejudice to principle of the present utility model and essence, but these changes all fall into protection range of the present utility model.Therefore the utility model technical scope is not limited to above-described embodiment.

Claims (4)

1. the three-phase PWM commutation system of modified model space vector control, comprise: three-phase PWM rectified power main circuit (1), voltage detecting circuit, current detection circuit, synchronizing voltage circuit and for Three-Phase PWM Rectifier being carried out to the dsp processor of modified model space vector control, three-phase PWM rectified power main circuit (1) respectively with voltage detecting circuit, current detection circuit, the input of synchronizing voltage circuit connects, voltage detecting circuit, current detection circuit, the output of synchronizing voltage circuit is connected with dsp processor, the output of dsp processor connects the driving input of six switching tubes of three-phase PWM rectified power main circuit (1).

2. the three-phase PWM commutation system of modified model space vector according to claim 1 control, is characterized in that described three-phase PWM rectified power main circuit (1) comprising: three-phase alternating-current supply (E), three-phase reactor (L), three-phase commutation bridge (K), buffer circuit (2), electric capacity (C) and load (R _l), three phase rectifier module has adopted six Switch Three-Phase half bridge circuit topologys, realizes AC and converts to DC; Described voltage detecting circuit sampling Hall voltage sensor senses AC three-phase alternating voltage and the three-phase commutation bridge output voltage of three-phase PWM rectified power main circuit (1); Described current detection circuit sampling Hall current sensor detects AC three-phase alternating current, i.e. three phase network input current; Described synchronizing voltage circuit adopts phase lock circuitry to calculate the locking phase of three phase network voltage.

3. the three-phase PWM commutation system of modified model space vector according to claim 2 control, is characterized in that: described buffer circuit (2) is composed in parallel by current-limiting resistance and relay, reduces ac-side current amplitude in conducting moment.

4. the three-phase PWM commutation system of modified model space vector according to claim 1 control, is characterized in that: described dsp processor adopts Texas Instruments's 2000 series DSP controllers.