CN102185505A - Method and system for controlling three-phase high-power-factor PWM (Pulse-Width Modulation) rectifier - Google Patents

Abstract

The invention discloses a method for controlling a three-phase high-power-factor PWM (Pulse-Width Modulation) rectifier. The method comprises the following steps of: (11) decoupling input current signals of two phases of three-phase alternating current into a network side watt component and a network side wattless component; (12) calculating a direct current output voltage value and a direct current output current value through a voltage outer ring sliding moding structural control algorithm to obtain a target watt component and a target wattless component; (13) performing current inner-ring control on the network side watt component, the network side wattless component, the target watt component and the target wattless component to obtain a variable under an alpha-beta coordinate; and (14) calculating the variable under the alpha-beta coordinate through a space vector algorithm to obtain a pulse width modulated wave for controlling a power switch tube in the rectifier. The invention further discloses a system for controlling the three-phase high-power-factor PWM rectifier. By adopting the method and the system, tracking of a current waveform along with a voltage waveform on a three-phase input side is realized, the current and voltage waveforms are ensured to be sine waves, the power factor of the rectifier is further realized to be 1, and the harmonic component content is very small.

Description

High Power Factor Three-Phase PWM Rectifier control method and system

Technical field

The present invention relates to the three phase rectifier technology, relate in particular to a kind of High Power Factor Three-Phase PWM Rectifier control method and system.

Background technology

Three-phase rectifier is to be used for three-phase alternating current is converted to a galvanic device.Three-phase rectifier generally is installed in the front end of power supply as the prime equipment of electric energy conversion.The rectifier system of domestic common employing is not at present controlled rectification, three-phase semiwave controlled rectification and three-phase bridge fully controlled rectifier, and wherein, the current waveform of not controlling rectification distorts obviously, harmonic content is very big and power factor is low, seriously disturbs power utilization network.

In addition, the control circuit of existing three-phase rectifier realizes that by analog circuit for example input, Voltage loop control and current loop control all are to make up control circuit with analog circuit.But external environments such as service time, temperature, humidity, vibration are bigger to the analog circuit influence, and simultaneously, this type of circuit is complicated, and most circuit use the discrete component assembling, cause the control circuit reliability low.

Summary of the invention

At the shortcoming of prior art, the purpose of this invention is to provide a kind of High Power Factor Three-Phase PWM Rectifier control method and system, the wave distortion of interchange input side is serious, harmonic content is big, power factor is low, the problem of control circuit poor reliability to solve.

To achieve these goals, technical scheme of the present invention is: a kind of High Power Factor Three-Phase PWM Rectifier control method comprises the steps that (11) are net side real component and net side idle component with three-phase alternating current two-phase input current signal decoupling zero wherein; (12) magnitude of voltage and the current value with direct current output draws target real component and target idle component by outer voltage Sliding mode variable structure control algorithm computation; (13) again net side real component, net side idle component, target real component and target idle component are controlled the variable that draws under the α β coordinate by current inner loop; (14) thus the variable under the aforementioned α β coordinate is obtained being used to control the pulse width modulated wave of rectifier internal power switching tube with the space vector algorithm computation.

In step (11), be that ac signal is done the conversion of abc coordinate to the dq coordinate, obtain net side real component and net side idle component under the dq coordinate.

In the preceding step (10) that also comprises of step (11), wherein the direct voltage after biphase current and the rectification and electric current after testing, convert digital signal to after the adjustment, filtering and are adjusted into zero cross signal as the phase angle reference point with the AC phase voltage with three-phase alternating current.

In step (10), further described four kinds of digital signals are reduced to actual value by calculating.

$\mathrm{Id}=\sqrt{\frac{2}{3}}*(\mathrm{Ia}*\mathrm{SINTABLE}[\mathrm{ACount}]+\mathrm{Ib}*\mathrm{SINTABLE}[\mathrm{BCount}]+\mathrm{Ic}*\mathrm{SINTABLE}[\mathrm{CCount}\left]\right)$

$\mathrm{Iq}=(\sqrt{\frac{2}{3}}*(\mathrm{Ia}*\mathrm{COSTABLE}[\mathrm{ACount}]+\mathrm{IbCOSTABLE}[\mathrm{ACount}]+\mathrm{Ic}*\mathrm{COSTABLE}[\mathrm{CCount}\left]\right)$

Wherein, Id, Iq is the current component under the dq coordinate, Ia, Ib, Ic is the current value under the abc coordinate, i.e. the value that obtains of actual samples, SINTABLE[ACount], SINTABLE[BCount], SINTABLE[BCount] be respectively the sine value at A, B, C three-phase phase angle, COSTABLE[ACount], COSTABLE[ACount], COSTABLE[CCount] be respectively A, B, C three-phase phase cosine of an angle value.

$\mathrm{Idref}=(((\mathrm{Udcref}-\mathrm{Udc}+(\mathrm{\β}/C*\mathrm{Idc}))*C)*\mathrm{Udc})/(\mathrm{\β}*(\sqrt{3}*\mathrm{Vrms}-*R*\mathrm{Idref}))$

Wherein, Idref is the reference value of Id, and Udcref is the reference value of step voltage after the rectification, and Udc is the actual value of step voltage after the rectification, and C is a level capacitance after the rectification, and Idc is a level current value after the rectification, β=0.03, and Vrms is an ac line voltage.

The present invention also provides a kind of High Power Factor Three-Phase PWM Rectifier control system, comprising:

The BOOST circuit is main circuit and electric energy main channel, is used to carry out three phase rectifier; Testing circuit is used to detect five kinds of signals, comprises three current signals, a voltage signal and an AC phase voltage signal; Signal adjustment circuit is used to adjust the five kinds of signal amplitudes and the Filtering Processing that detect; Control circuit, being used for adjusted analog signal conversion is digital signal, and calculates the generation pulse-width modulation control signal with outer voltage Sliding mode variable structure control algorithm, current inner loop control and space vector control algolithm; Drive circuit, the pulse-width modulation control signal that described control circuit is exported is converted to the control signal that drives the main circuit power switch pipe, realizes the control to power switch pipe; The protective circuit plate is used for the overvoltage/undervoltage protection of input; Power supply circuit board is to each circuit supply of High Power Factor Three-Phase PWM Rectifier system.

With respect to prior art, the present invention with alternating current and dc signal by the controlled drive signal of computing, the through and off of power switch pipe on the drive signal control main circuit of these controls, thereby realize the current waveform floating voltage waveform of three-phase input side, guarantee that current-voltage waveform is sine wave, so the power factor that realizes rectifier reach 1 and harmonic components content very little.

Description of drawings

The present invention is described in further detail below in conjunction with accompanying drawing.

Fig. 1 is a High Power Factor Three-Phase PWM Rectifier control method schematic diagram of the present invention.

Fig. 2 is a High Power Factor Three-Phase PWM Rectifier of the present invention system main circuit topological structure schematic diagram.

Fig. 3 is a High Power Factor Three-Phase PWM Rectifier system module structural representation of the present invention.

Fig. 4 is a High Power Factor Three-Phase PWM Rectifier system hardware structure schematic diagram of the present invention.

Fig. 5 uses Computer Simulation design sketch of the present invention.

Fig. 6 A is that High Power Factor Three-Phase PWM Rectifier is used control algolithm of the present invention front and back net side waveform comparison diagram.

When Fig. 6 B is High Power Factor Three-Phase PWM Rectifier system No Load Start after the rectification level direct voltage and current on line side oscillogram.

The direct voltage and the current on line side oscillogram of level after Fig. 6 C to be the High Power Factor Three-Phase PWM Rectifier system from zero load to band carry rectification.

Embodiment

See also Fig. 1, control method of the present invention mainly comprises the steps: to be converted to digital signal after signal that (S11) obtains sampling is adjusted amplitude; (S12) to the ac-side current part dq decoupling zero conversion in the described digital signal, wherein the phase angle is provided by the adjusted zero cross signal of AC phase voltage; (S13) direct voltage in the described digital signal and electric current are done the outer voltage Sliding mode variable structure control; (S14) current inner loop is controlled, and coordinate is transformed to α β coordinate by dq; (S15) space vector algorithm is calculated the drive waveforms of 6 brachium pontis.

In step (S11), specifically can pass through voltage transformer summation current transformer sampled voltage and current signal, and adjust signal amplitude by a series of circuit such as amplifiers, the scope that the ADC port that makes the signal amplitude size satisfy DSP requires, and in the ADC of DSP, finish analog-to-digital conversion.

In step (S12), concrete work is that the current signal of three-phase alternating current side that sampling is obtained is done the conversion of abc coordinate to the dq coordinate, feasible the electrical signal conversion of three-phase is become real component and idle component, uses following formula in computing:

$\mathrm{Id}=\sqrt{\frac{2}{3}}*(\mathrm{Ia}*\mathrm{SINTABLE}[\mathrm{ACount}]+\mathrm{Ib}*\mathrm{SINTABLE}[\mathrm{BCount}]+\mathrm{Ic}*\mathrm{SINTABLE}[\mathrm{CCount}\left]\right)$

$\mathrm{Iq}=(\sqrt{\frac{2}{3}}*(\mathrm{Ia}*\mathrm{COSTABLE}[\mathrm{ACount}]+\mathrm{IbCOSTABLE}[\mathrm{ACount}]+\mathrm{Ic}*\mathrm{COSTABLE}[\mathrm{CCount}\left]\right)$

Wherein: Id, Iq is the current component under the dq coordinate, Ia, Ib, Ic is the current value under the abc coordinate, i.e. the value that obtains of actual samples.SINTABLE[ACount], SINTABLE[BCount], SINTABLE[BCount] be respectively the sine value at A, B, C three-phase phase angle, COSTABLE[ACount], COSTABLE[ACount], COSTABLE[CCount] be respectively A, B, C three-phase phase cosine of an angle value.Thereby the zero crossing that AC is caught by the seizure pin of DSP in A, B, C three-phase phase angle calculates.

In step (S13), concrete work is the outer voltage Sliding mode variable structure control, and Sliding mode variable structure control has very strong robustness and dynamic response.This algorithm is the algorithm that has novelty in the industrial control field.Variable structure control method is a kind of nonlinear Control in essence, its nonlinear characteristic shows as the discontinuity of control, characteristics are that the structure of system is unfixing, but can constantly change according to system's current state in dynamic process, force the sliding mode motion of system according to appointment.In computing, use following formula:

$\mathrm{Idref}=(((\mathrm{Udcref}-\mathrm{Udc}+(\mathrm{\β}/C*\mathrm{Idc}))*C)*\mathrm{Udc})/(\mathrm{\β}*(\sqrt{3}*\mathrm{Vrms}-*R*\mathrm{Idref}))$

Wherein: Idref is the reference value of Id, and Udcref is the reference value of step voltage after the rectification, and Udc is the actual value of step voltage after the rectification, and C is a level capacitance after the rectification, and Idc is a level current value after the rectification, β=0.03, and Vrms is an ac line voltage.

In step (S14), concrete work is to carry out the current inner loop computing, and control variables is transformed to α β coordinate from coordinate dq.In step (S15), concrete work is that the value of utilizing step (S14) computing to obtain is carried out space vector calculating, and the drive waveforms of controlled usefulness.Control method of the present invention is simple, and the current waveform distortion is little, and Digital Realization is convenient, can obviously reduce the harmonic components of ac-side current, improves voltage utilization (higher by 15% than SPWM).

See also Fig. 2, what the main circuit of High Power Factor Three-Phase PWM Rectifier system adopted is the Three-phase PWM Voltage Rectifier circuit, also can be described as three-phase BOOST circuit.Three inlet wire inductance in the circuit adopt the 4mH inductance, and power switch pipe adopts the CM150DY-24H of Mitsubishi.

See also Fig. 3, Fig. 4, whole system comprises BOOST circuit, testing circuit, signal adjustment circuit, DSP control circuit, drive circuit, protective circuit and power circuit.Wherein, the DSP control circuit can select for use the TMS320F2812 of TI company as core processor, and all control algolithms all realize in DSP.DSP does not have external EEPROM or SRAM etc., so this control system is the control system of a minimum.Enter in the DSP after the ADC employing of outside analog signal through 15KHz, AC phase voltage zero crossing is the computing starting point of DSP, according to the frequency calculation of 15Kz.The electrical network cycle is realized with the software phase-lock mode by DSP.In addition,,,, finish the various control algorithm, adopt the method for tabling look-up to ask for the sine and cosine value in the present embodiment for improving the DSP performance if adopt real-time Calculation Method then can consume a large amount of operation time of DSP because the TMS320F2812 that adopts is a fixed DSP.

See also Fig. 5, current on line side has been followed the tracks of voltage on line side well, and not only phase place is identical for both, and all is sinusoidal wave.In addition, under the situation of load increase and load minimizing, current on line side also can be followed the tracks of voltage on line side well.

See also Fig. 6 A, after using the present invention, the current on line side waveform is transformed into sine wave by the very serious waveform of original distortion; See also Fig. 6 B, the present invention can start under zero load, and the level direct voltage is very steady after the rectification; See also Fig. 6 C, to band idling when changing, a level direct voltage does not have overshoot after the rectification in zero load in the present invention, and current on line side converts sine wave at once.Therefore can find out effect and system's operation stability of High Power Factor Three-Phase PWM Rectifier control method of the present invention from above-mentioned each figure.

Use rectifier power factor height of the present invention, harmonic content is little, particularly in the high-power electric and electronic field, has solved that power electronic equipment input current waveform seriously distorts, the low problem of power factor; Suppressed the harmonic wave that power electronic equipment produces simultaneously, made to guarantee the electric current and the voltage same-phase of input that substantially power consumption equipment is pollution-free to electrical network, and have energy-conserving action.In addition, use rectifier of the present invention can not only be fine control exchange the power factor of input side, and direct voltage also is controlled.

Using rectifier input of the present invention does not need center line, and this can't realize in other is formed the power factor calibration system of three-phase by three single-phase merging.

By rectifier control signal digitized processing mode, efficiently the rectifier control signal is sampled and handle with high speed digital signal processor and specific software algorithm, significantly improve the reliability of control circuit, reduce service time, external environments such as temperature, humidity, vibration influence control circuit.In the time will changing components of system as directed function and performance, only need can achieve the goal with adjusting the software control circuit parameter, reduce system cost.

Claims (7)

1. a High Power Factor Three-Phase PWM Rectifier control method comprises the steps,

(11) be net side real component and net side idle component with three-phase alternating current two-phase input current signal decoupling zero wherein;

(12) magnitude of voltage and the current value with direct current output draws target real component and target idle component by outer voltage Sliding mode variable structure control algorithm computation;

(13) again net side real component, net side idle component, target real component and target idle component are controlled the variable that draws under the α β coordinate by current inner loop;

(14) thus the variable under the aforementioned α β coordinate is obtained being used to control the pulse width modulated wave of rectifier internal power switching tube with the space vector algorithm computation.

2. High Power Factor Three-Phase PWM Rectifier control method according to claim 1 is characterized in that, in step (11), is that ac signal is done the conversion of abc coordinate to the dq coordinate, obtains net side real component and net side idle component under the dq coordinate.

3. High Power Factor Three-Phase PWM Rectifier control method according to claim 1, it is characterized in that, in the preceding step (10) that also comprises of step (11), wherein the direct voltage after biphase current and the rectification and electric current after testing, convert digital signal to after the adjustment, filtering and are adjusted into zero cross signal as the phase angle reference point with the AC phase voltage with three-phase alternating current.

4. High Power Factor Three-Phase PWM Rectifier control method according to claim 3 is characterized in that, further described four kinds of digital signals is reduced to actual value by calculating in step (10).

5. High Power Factor Three-Phase PWM Rectifier control method according to claim 2 is characterized in that,

$\mathrm{Iq}=(\sqrt{\frac{2}{3}}*(\mathrm{Ia}*\mathrm{COSTABLE}[\mathrm{ACount}]+\mathrm{IbCOSTABLE}[\mathrm{ACount}]+\mathrm{Ic}*\mathrm{COSTABLE}[\mathrm{CCount}\left]\right)$

Wherein, Id, Iq is the current component under the dq coordinate, Ia, Ib, Ic is the current value under the abc coordinate, i.e. the value that obtains of actual samples, SINTABLE[ACount], SINTABLE[BCount], SINTABLE[BCount] be respectively the sine value at A, B, C three-phase phase angle, COSTABLE[ACount], COSTABLE[ACount], COSTABLE[CCount] be respectively A, B, C three-phase phase cosine of an angle value.

6. High Power Factor Three-Phase PWM Rectifier control method according to claim 5 is characterized in that,

Wherein, Idref is the reference value of Id, and Udcref is the reference value of step voltage after the rectification, and Udc is the actual value of step voltage after the rectification, and C is a level capacitance after the rectification, and Idc is a level current value after the rectification, β=0.03, and Vrms is an ac line voltage.

7. High Power Factor Three-Phase PWM Rectifier control system comprises:

The BOOST circuit is main circuit and electric energy main channel, is used to carry out three phase rectifier;

Testing circuit is used to detect five kinds of signals, comprises three current signals, a voltage signal and an AC phase voltage signal;

Signal adjustment circuit is used to adjust the five kinds of signal amplitudes and the Filtering Processing that detect;

Control circuit, being used for adjusted analog signal conversion is digital signal, and calculates the generation pulse-width modulation control signal with outer voltage Sliding mode variable structure control algorithm, current inner loop control and space vector control algolithm;

Drive circuit, the pulse-width modulation control signal that described control circuit is exported is converted to the control signal that drives the main circuit power switch pipe, realizes the control to power switch pipe;

Protective circuit is used for the overvoltage/undervoltage protection of input;

Power circuit is to each circuit supply of High Power Factor Three-Phase PWM Rectifier system.

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