CN104167941B - Three-phase PWM rectifier control method - Google Patents

Abstract

The invention provides a three-phase PWM rectifier control method which includes a direct current capacitor energy storage outer loop control method and a grid-side current inner loop control method. The method includes the steps that direct current capacitor stored energy of a rectifier is fed back as a whole, given capacitor charging power is output after calculation is finished through an energy PI adjuster, grid-side input power is obtained by adding load power to the given capacitor charging power, a given grid-side d-axis current value i*d is obtained by dividing grid-side input power by the grid-side d-axis voltage component, a given q-axis current value i*q is obtained according to the relation between given d-axis current and given q-axis current, a grid-side voltage control value ud and a grid-side voltage control value uq are obtained in sequence according to the grid-side current inner loop control method, given voltage values are obtained through feedforward and decoupling of the ud, uq and the network voltage, given phase voltage output values are obtained through Park inverse transformation and Clark inverse transformation, and switch control signals Sa, Sb and Sc used for driving a PWM rectifier bridge arm electronic switch are obtained finally through space vector pulse width modulation. By means of the method, the dynamic response performance of a three-phase PWM rectifier can be improved greatly, and the method is particularly suitable for fast charging of electric cars and other occasions having high requirements for the response performance of the three-phase PWM rectifier.

Description

A kind of control method of Three-Phase PWM Rectifier

Technical field

The present invention relates to electric and electronic technical field, more particularly to a kind of controlling party of three-phase power electronics converting means Method.

Background technology

Traditional commutator is made up of diode or IGCT, and this kind of commutator has Harmonics of Input content height, defeated Enter power factor low, energy unidirectional delivery, the shortcomings of DC voltage is uncontrollable.Since the later stage eighties 20th century start by PWM (Pulse Width Modulation, pulse width modulation) technology is introduced in commutator control, this High Power Factor PWM rectifier technology has become the focus of domestic and international research.Voltage-source type PWM commutation technique compared with traditional commutation technique, PWM rectifier has the advantages that to realize that energy in bidirectional flow, DC voltage be controlled, low Harmonics of Input, power factor are high, It is truly realized " green energy conversion ", be widely used in Active Power Filter-APF, static reacance generator, high-voltage dc transmission Electricity, the field such as Electrified Transmission.

With the variation of application scenario, to quiet, dynamic property the requirement of voltage-source type PWM commutation technique also increasingly Many.At present, the main control strategy of PWM rectifier has：Vector controlled based on grid voltage orientation, based on Virtual shipyard orientation Vector controlled, the direct Power Control based on grid voltage orientation and based on Virtual shipyard orientation direct Power Control.Base Vector controlled in grid voltage orientation is capable of the conversion of power four-quadrant, and has dynamic response is fast, steady-state behaviour is good etc. Advantage, is easy to the realization of DSP.Quiet, the dynamic property of the vector control method based on Virtual shipyard orientation compare voltage oriented control Superior, its output DC voltage dynamic response contrast is fast, and input current waveform aberration rate is smaller, but algorithm is complicated.It is based on The direct Power Control of grid voltage orientation adopts instantaneous power control, has High Power Factor, low THD, algorithm and system knot The simple feature of structure, causes the concern of a lot of research worker.Based on the feature of direct Power Control of Virtual shipyard orientation it is System structure is simple, can effectively reduce number of sensors, strong antijamming capability, electrical network input current abnormality is little, have excellent Instantaneous power static and dynamic performance.

With the increase of voltage type PWM rectifier range of application, in the case of ensureing stability, PWM rectifier is moved State property requires more and more higher.In above control method, direct Power Control has good rapidity.Due to direct Poewr control method designs frequently with the two close cycles of Voltage Feedback outer shroud, current feedback internal ring, and is selected using the stagnant ring of power Switch list, thus leading to switching frequency not fixed, the switching frequency of change is unfavorable for that AC reactance wave filter designs.Simultaneously by Carry out data acquisition and algorithm process in the sampling period higher A/D converter needing high speed and processor, be not easy to system real Existing.

Content of the invention

In view of the deficiency of prior art, a kind of present invention control method of Three-Phase PWM Rectifier of offer, the method can be big The big dynamic response performance improving Three-Phase PWM Rectifier.

The scheme that this method solves above-mentioned technical problem is as follows：

A kind of control method of Three-Phase PWM Rectifier, including in DC capacitor energy storage outer loop control method and current on line side Ring control method, specifically includes following steps：

1) DC capacitor energy storage outer loop control method：

A) it is utilized respectively the voltage sensor of alternating current net side and current sensor gathers the ac phase voltage e of alternating current net side_a、 e_b、e_cWith AC phase currents i_a、i_b、i_c, and by CLARK conversion and PARK conversion, press Formulas I) with II) will exchange respectively mutually electric Pressure e_a、e_b、e_cWith AC phase currents i_a、i_b、i_cFrom three-phase static coordinate system is changed to two-phase rotating coordinate system：

Formulas I) and II) in, θ be current voltage phase angle, meet Formula Il I)：

B) DC voltage sensor sample is utilized to obtain DC voltage u_dc, and calculate acquisition DC bus capacitor energy storage

C) by DC bus capacitor energy storage E_CAs feedback, with given DC energy storage E^* _CAfter subtracting each other, through energy pi regulator fortune Calculate the given electric capacity charge power p of output, more given electric capacity charge power p is added bearing power p_L, obtain net side input power p_grid=p+p_L；

2) current on line side internal ring control method：

D) by step C) net side input power p that obtains_gridDivided by the d shaft voltage component e under two-phase rotating coordinate system_d? D axle current on line side set-point under two-phase rotating coordinate systemBy the d axle current on line side set-point under two-phase rotating coordinate systemWith the d shaft current component i under two-phase rotating coordinate system_dSubtract each other, through d shaft current pi regulator computing, obtain biphase rotation and sit D axle net side output voltage u under mark system_d, due to d axle current on line side set-pointWith q axle current on line side set-pointMeet and close System：Therefore, similarly by the q axle current on line side set-point under two-phase rotating coordinate systemSit with biphase rotation Q shaft current component i under mark system_qSubtract each other, through q shaft current pi regulator computing, obtain the q axle net side under two-phase rotating coordinate system Output voltage u_q；

E) ignore switching loss, by d axle net side output voltage u_dWith q axle net side output voltage u_qPress formula IV) feedovered Decoupling, the d axle net side respectively obtaining control system output gives voltage u^* _dGive voltage u with q axle net side^* _q：

Formula IV) in, ω is line voltage angular frequency, and L is the inductance value of reactor；

F) d axle net side is given voltage u^* _dGive voltage u with q axle net side^* _qCarry out PARK inverse transformation and CLARK inverse transformation, The PWM rectifier obtaining under three-phase static coordinate system gives phase voltage output valveAdjusted by space vector pulse width System finally gives the switch controlling signal S for driving PWM rectifier brachium pontis electrical switch_a、S_b、S_c.

The present invention provide a kind of advantage of the control method of Three-Phase PWM Rectifier and have the beneficial effects that：By direct current The energy of lateral capacitance storage, as outer loop feedback controling parameter, substantially improves the dynamic response performance of Three-Phase PWM Rectifier, makes Obtain the regulating time of step response of commutator and overshoot greatly reduces, be highly suitable for such as electric vehicle rapid charging etc. Higher occasion is required to Three-Phase PWM Rectifier response performance.The concrete analysis of its principle is as follows：

Due to being Three-Phase PWM Rectifier for control object, and input voltage adopts three-phase no center line connected mode, ignores 0 Axle component, by being down-converted to two-phase rotating coordinate system three-phase phase voltage and phase current from three phase coordinate systems, obtains voltage Shown in equilibrium relation such as following formula (1)：

In formula (1), L and R is respectively input inductance value and the parasitic resistance values of three-phase alternating current net side, e_d、e_qRespectively biphase The d shaft voltage component of voltage on line side and q shaft voltage, u under rotating coordinate system_d、u_qIt is respectively commutator side under two-phase rotating coordinate system The d shaft voltage component of voltage and q shaft voltage；

Due to being down-converted to two-phase rotating coordinate system three-phase phase voltage and phase current from three phase coordinate systems, using electrical network Voltage oriented, and during d overlapping of axles under line voltage vector and two-phase rotating coordinate system, three-phase phase voltage is in two cordic phase rotators The component e under q axle under system_q=0, shown in the current relationship such as following formula (2) of DC side and AC：

In formula (2), i_C、i_dc、i_L、u_dcBe respectively DC bus capacitor electric current, DC side total current, DC side load current and DC voltage；

The Section 1 of formula (1) is multiplied by the alternating current net side current component i under two-phase rotating coordinate system_d, add that Section 2 is taken advantage of With alternating current net side current component i_q, then the Section 2 of formula (1) is multiplied by the alternating current net side current component under two-phase rotating coordinate system i_d, deduct Section 1 and be multiplied by alternating current net side current component i_q, active power and the reactive power of Three-Phase PWM Rectifier can be obtained respectively Commutative relation, such as shown in following formula (3)：

In formula (3), the active power that the above formula left side inputs for electrical network, the right Section 1 absorbs for Three-Phase PWM Rectifier Active power, Section 2 is the active power that on inductance, dead resistance consumes, and Section 3 is when in inductance, magnetic field energy increases The active power consuming, during stable state, Section 3 value is zero；The reactive power that the following formula left side inputs for electrical network, the right Section 1 is The reactive power that Three-Phase PWM Rectifier absorbs, Section 2 is the reactive power consuming on inductance, and Section 3 is magnetic field storage in inductance The reactive power being consumed during energy sum variation, during stable state, Section 3 value is zero.Therefore, required reactive power on inductance is whole There is provided by Three-Phase PWM Rectifier.

Ignore the switching loss of Three-Phase PWM Rectifier, simultaneous formula (2) and formula (3) understand, DC side power P meets following formula (4)：

In formula (4), p_LFor bearing power；

From in formula (4), a DC side power part makes capacitance energy storage increase, and a part provides load consuming power, The d axle component of the electric current due to absorbing from electrical network will all provide commutator internal consumption and DC side power, the q axle of electric current again Component is idle component.Due to the dead resistance R very little of inductance, it is negligible, simultaneous formula (3) and formula (4) can obtain electrical network The d axle component of the electric current absorbing meets following formula (5)：

Therefore, using Three-Phase PWM Rectifier DC bus capacitor energy storage as outer loop feedback controling parameter, and obtain three-phase The electrical network of PWM rectifier absorbs the d axle component of electric current, you can complete the output control to commutator, and meeting makes it be rapidly achieved Rated output.

Brief description

Fig. 1 is the main circuit topological structure schematic diagram of three-phase two level PWM rectifier.

Fig. 2 is the flow chart of Three-Phase PWM Rectifier control method of the present invention.

Fig. 3 is the Control system architecture block diagram of the Three-Phase PWM Rectifier of the structure using control method of the present invention.

The Three-Phase PWM Rectifier that Fig. 4 (a)～Fig. 4 (c) controls for the control method that prior art provides opens in zero load respectively Dynamic, shock load and band carry DC voltage waveform during startup, AC a phase voltage and current waveform, two cordic phase rotators D axle current on line side component i under system_dOscillogram.

The Three-Phase PWM Rectifier that Fig. 5 (a)～Fig. 5 (c) controls for the control method that the present invention provides opens in zero load respectively Dynamic, shock load and band carry DC voltage waveform during startup, AC a phase voltage and current waveform, two cordic phase rotators D axle current on line side component i under system_dOscillogram.

Specific embodiment

Example 1

This example is one and adopts control method control technology parameter of the present invention three-phase two level PWM rectification as shown in table 1 The control process of device, describes the present invention below in conjunction with the accompanying drawings.

Parameter name	Numerical value
		DC bus capacitor	2010uF
Net side inductance	3mH
		Load resistance	100 Ω (power 2kW)
Switching frequency	6KHz
		DC bus-bar voltage	450V
Net side line voltage	240V

Table 1

The main circuit structure of three-phase two level PWM rectifier that control method of the present invention controls is as shown in figure 1, wherein Three phase network electromotive force is e_a、e_b、e_c, connect through the upper underarm that three-phase linear inductance L is respectively connected to each phase PWM rectifier brachium pontis Place, three-phase net side phase current is respectively i_a、i_b、i_c.DC side outfan is parallel with filter capacitor C DC load resistance R_L.It is based on This circuit topology, sets up control system as shown in Figure 3, and its control method flow process is as shown in Fig. 2 comprise the following steps that：

1) DC capacitor energy storage outer loop control method：

A) it is utilized respectively the voltage sensor of alternating current net side and current sensor gathers the ac phase voltage e of alternating current net side_a、 e_b、e_cWith AC phase currents i_a、i_b、i_c, and by CLARK conversion and PARK conversion, press Formulas I) with II) will exchange respectively mutually electric Pressure e_a、e_b、e_cWith AC phase currents i_a、i_b、i_cFrom three-phase static coordinate system is changed to two-phase rotating coordinate system：

Formulas I) and II) in, θ be current voltage phase angle, meet Formula Il I)：

B) DC voltage sensor sample is utilized to obtain DC voltage u_dc, and calculate acquisition DC bus capacitor energy storage

C) by DC bus capacitor energy storage E_CAs feedback, with given DC energy storage E^* _CAfter addition, through energy pi regulator fortune Calculate the given electric capacity charge power p of output, more given electric capacity charge power p is added bearing power p_L, obtain net side input power p_grid=p+p_L；

2) current on line side internal ring control method：

D) by step C) net side input power p that obtains_gridDivided by the d shaft voltage component e under two-phase rotating coordinate system_d? D axle current on line side set-point under two-phase rotating coordinate systemBy the d axle current on line side set-point under two-phase rotating coordinate systemWith the d shaft current component i under two-phase rotating coordinate system_dSubtract each other, through d shaft current pi regulator computing, obtain two cordic phase rotators D axle output voltage u under system_d, due to d axle current on line side set-pointWith q axle current on line side set-pointMeet relation：Therefore, similarly by the q axle current on line side set-point under two-phase rotating coordinate systemWith two-phase rotating coordinate system Under q shaft current component i_qSubtract each other, through q shaft current pi regulator computing, obtain the q axle output voltage under two-phase rotating coordinate system u_q；

E) ignore switching loss, by d axle output voltage u_dWith q axle output voltage u_qPress formula IV) carry out Feedforward Decoupling, point The d axle net side not obtaining control system output gives voltage u^* _dGive voltage u with q axle net side^* _q：

Formula IV) in, ω is line voltage angular frequency, and L is the inductance value of reactor；

F) d axle net side is given voltage u^* _dGive voltage u with q axle net side^* _qCarry out PARK inverse transformation and CLARK inverse transformation, Three-phase two level PWM rectifier obtaining under three-phase static coordinate system gives phase voltage output valveBy space Vector Pulse Width Modulation finally gives the switch controlling signal for driving three-phase two level PWM rectifier each phase brachium pontis electrical switch S_a、S_b、S_c.

Example 2

For verifying the control performance of control method provided by the present invention, this example will be anti-for the employing voltage described in prior art Control method employed in feedback outer shroud, the direct Power Control method of two close cycles design of current feedback internal ring and example 1 is to skill Art parameter three-phase as shown in table 1 two level PWM rectifier is respectively controlled, and produced using Aglient company of the U.S. Model MSO-X3014A oscillograph gather respectively No Load Start, shock load and with carry start when DC voltage waveform, D axle current on line side component i under AC a phase voltage and current waveform, two-phase rotating coordinate system_dWaveform, collection result such as Fig. 4 With shown in Fig. 5.Comparison Fig. 4 and Fig. 5 it is apparent that

Under the conditions of No Load Start, with reference to Fig. 4 (a) and Fig. 5 (a), in No Load Start, overshoot exceedes prior art 40V, the rise time reaching given voltage is about 75ms, and regulating time is about 150ms；And control method provided by the present invention In No Load Start, overshoot is only 30V, and the rise time reaching given voltage is about 60ms, and regulating time is about 75ms.

Under the conditions of shock load, with reference to Fig. 4 (b) and Fig. 5 (b), prior art in shock load, Voltage Drop ratio More than 35V, the adjustment and recovery time is about 150ms；And control method provided by the present invention is in shock load, Voltage Drop ratio Example is about 25V, and the adjustment and recovery time is about 50ms.

Carry under entry condition in band, with reference to Fig. 4 (c) and Fig. 5 (c), when band carries and starts, voltage overshoot surpasses prior art Cross 15V, the rise time reaching given voltage is about 120ms, and regulating time is about 170ms；And control provided by the present invention When band carries and starts, voltage overshoot is about 120ms less than 10V, the rise time reaching given voltage to method, and regulating time is about For 130ms.

It will be apparent that under the same conditions, the dynamic response performance of the control method that the present invention provides is apparently higher than existing skill Art.It is highly suitable for the field higher to three-phase two level PWM rectifier response performance requirement such as such as electric vehicle rapid charging Close.

Claims (1)

1. a kind of control method of Three-Phase PWM Rectifier, including DC capacitor energy storage outer loop control method and current on line side internal ring Control method, specifically includes following steps：

1) DC capacitor energy storage outer loop control method：

A) it is utilized respectively the voltage sensor of alternating current net side and current sensor gathers the ac phase voltage e of alternating current net side_a、e_b、e_c With AC phase currents i_a、i_b、i_c, and by CLARK conversion and PARK conversion, press Formulas I) and II) respectively by ac phase voltage e_a、e_b、e_cWith AC phase currents i_a、i_b、i_cFrom three-phase static coordinate system is changed to two-phase rotating coordinate system：

$\left\{\begin{array}{c}{e}_{\mathrm{\α}}=\sqrt{\frac{2}{3}}{e}_a-\sqrt{\frac{1}{6}}(e_b+e_c)\\ e_{\mathrm{\β}}=\frac{1}{\sqrt{2}}(e_b-e_c)\end{array}\right.---I)$

$\left\{\begin{array}{c}{e}_d=e_{\mathrm{\α}}*\cos \left(\mathrm{\θ}\right)+e_{\mathrm{\β}}*\sin \left(\mathrm{\θ}\right)\\ e_q={-e}_{\mathrm{\α}}*\sin +e_{\mathrm{\β}}*\cos \left(\mathrm{\θ}\right)\end{array}\right.$

$\left\{\begin{array}{c}{i}_{\text{\α}}=\sqrt{\frac{2}{3}}{i}_a-\sqrt{\frac{1}{6}}(i_b+i_c)\\ i_{\mathrm{\β}}=\frac{1}{\sqrt{2}}(i_b-i_c)\end{array}\right.---\mathrm{II})$

$\left\{\begin{array}{c}{i}_d=i_{\mathrm{\α}}*\cos \left(\mathrm{\θ}\right)+i_{\mathrm{\β}}*\sin \left(\mathrm{\θ}\right)\\ i_q={-i}_{\mathrm{\α}}*\sin \left(\mathrm{\θ}\right)+i_{\mathrm{\β}}*\cos \left(\mathrm{\θ}\right)\end{array}\right.$

Formulas I) and II) in, θ be current voltage phase angle, meet Formula Il I)：

$\left\{\begin{array}{c}\cos \mathrm{\θ}=\frac{e_{\mathrm{\α}}}{\sqrt{e{\mathrm{\α}}^2+e{\mathrm{\β}}^2}}\\ \sin \mathrm{\θ}=\frac{e_{\mathrm{\β}}}{\sqrt{e{\mathrm{\α}}^2+e{\mathrm{\β}}^2}}\end{array}\right.---\mathrm{III});$

B) DC voltage sensor sample is utilized to obtain DC voltage u_dc, and calculate acquisition DC bus capacitor energy storage $E_C=\frac{1}{2}C{\left(u_{\mathrm{dc}}\right)}^2;$

C) by DC bus capacitor energy storage E_CAs feedback, with given DC energy storage E^* _CAfter subtracting each other, defeated through energy pi regulator computing Go out given electric capacity charge power p, more given electric capacity charge power p is added bearing power p_L, obtain net side input power p_grid= p+p_L；

2) current on line side internal ring control method：

D) by step C) net side input power p that obtains_gridDivided by the d shaft voltage component e under two-phase rotating coordinate system_dObtain two D axle current on line side set-point under cordic phase rotator systemBy the d axle current on line side set-point under two-phase rotating coordinate systemWith D shaft current component i under two-phase rotating coordinate system_dSubtract each other, through d shaft current pi regulator computing, obtain two-phase rotating coordinate system Under d axle output voltage u_d, due to d axle current on line side set-pointWith q axle current on line side set-pointMeet relation：Therefore, similarly by the q axle current on line side set-point under two-phase rotating coordinate systemWith two-phase rotating coordinate system Under q shaft current component i_qSubtract each other, through q shaft current pi regulator computing, obtain the q axle output voltage under two-phase rotating coordinate system u_q；

E) ignore switching loss, by d axle output voltage u_dWith q axle output voltage u_qPress formula IV) carry out Feedforward Decoupling, respectively D axle net side to control system output gives voltage u^* _dGive voltage u with q axle net side^* _q：

$\left\{\begin{array}{c}{u}_d^{*}=e_d+{\mathrm{\ωLi}}_q-u_d\\ u_q^{*}=u_q-{\mathrm{\ωLi}}_d-e_q\end{array}\right.---\mathrm{IV})$

Formula IV) in, ω is line voltage angular frequency, and L is the inductance value of reactor；

F) d axle net side is given voltage u^* _dGive voltage u with q axle net side^* _qCarry out PARK inverse transformation and CLARK inverse transformation, obtain PWM rectifier under three-phase static coordinate system gives phase voltage output valveBy space vector pulse width modulation Obtain the switch controlling signal S for driving PWM rectifier brachium pontis electrical switch eventually_a、S_b、S_c.