CN101917158A - Dead-zone compensation method for voltage source inverter - Google Patents

Abstract

The invention relates to a dead-zone compensation method for a voltage source inverter. The method comprises the following steps of: performing dead-time compensation according to the acting time t1 and t2 of two non-zero base voltage vectors in a pulse-width modulation (PWM) period Ts and the practical dead time Td of the voltage source inverter based on the conventional space vector pulse width modulation (SVPWM) modulation strategy; adding two dead-time compensation time tcom1 and tcom2 and the acting time t1 and t2 of the two non-zero base voltage vectors to obtain new acting time t11 and t22 of the two non-zero base voltage vectors in the PWM period; and operating the new acting time t11 and t22 of the two non-zero base voltage vectors by using the SVPWM modulation strategy to generate a needed PWM pulse and finally realize deal-time compensation and zero-current clamping effect inhibition.

Description

A kind of dead-zone compensation method that is used for voltage source inverter

Technical field

The present invention relates to a kind of dead-zone compensation method of voltage source inverter.

Background technology

The same brachium pontis of three-phase voltage source inverter (VSI) up and down pipe to open signal be complementary, in order to prevent to lead directly to, must artificially during the power tube switch motion, insert one section Dead Time.Its cumulative effect causes motor phase voltage and phase current distortion, zero current clamp effect and torque and speed ripple, and systematic function reduces mistake | do not find Reference source.。Therefore for improving systematic function, voltage source inverter (VSI) dead band research is very important.The dead band fine compensation generally needs two conditions: the error voltage Δ V and the sense of current are correctly estimated.Error voltage is asked for and is based on the mean error theory, obtains desirable output voltage of voltage source inverter (VSI) and actual output voltage mean difference in one-period, according to each phase current polarity it is added in the command voltage then to compensate.It is subject matter that current polarity detects, and will definitely not make bucking voltage become disturbance voltage because current polarity detects.During low frequency,, accurately detect electric current and pass through unusual difficulty at zero point because PWM noise, zero current clamp phenomenon, electric current pass through the speed at zero point and pacing up and down when passing through etc.

Application number is 00122378 patent " dead-zone compensation method of frequency converter ", in the rotating coordinate system of space voltage vector orientation, obtain two shaft currents, obtain the azimuth of resultant current vector after the low-pass filtering, determine three-phase phase current polarity with this then, but because the problem of using this method of low pass filter can bring the current vector angle estimation to lag behind, when low frequency, be difficult to simultaneously guarantee the current vector angle estimation precision, and this method more complicated has taken a large amount of cpu resources.Application number is that 200610144322 patent " a kind of dead-zone compensation method of space vector pulse width modulation output " is according to phase current polarity each sector compensation PWM pulsewidth at the SVPWM modulation strategy, the problem that this method exists current polarity to detect, simultaneously owing to be to compensate according to the PWM pulsewidth of phase current polarity to each sector, have 36 kinds of compensation situations, so more complicated, and taken a large amount of cpu resources.Application number is that 01144167 patent " a kind of method that is used for the PWM-type frequency-conversion power supply dead area compensation " relies on hardware circuit and detects phase voltage positive and negative in Dead Time, obtain dead area compensation direction accurately, but this method is to the insulation request height of voltage sampling circuit, and anti-interference, strong and weak electricity insulation request to system during design are very high.These method implementation procedures are all complicated, perhaps take the more resource of CPU, perhaps rely on the hardware circuit of more complicated.

Summary of the invention

The objective of the invention is to overcome and rely on the current polarity detection in the existing dead-time Compensation Technology or consume the drawback that a large amount of cpu resources bring, a kind of dead-zone compensation method that is used for voltage source inverter (VSI) is proposed, the present invention can be on traditional SVPWM modulation strategy basis, hardware detecting circuit that need not be extra, also need not complicated algorithm, more need not waste limited cpu resource, only need to use simple formula, just can obtain dead area compensation effect preferably by several instructions, and can effectively suppress zero current clamp effect.

The dead-zone compensation method that the present invention is used for voltage source inverter is by the following technical solutions:

The actual Dead Time of voltage source inverter is a Dead Time sum of artificially setting Dead Time and the equivalence of voltage source inverter nonlinear characteristic, uses T _dExpression.The actual Dead Time of voltage source inverter can obtain by off-line measurement, also can obtain by online estimation.

The present invention on the basis of traditional SVPWM modulation strategy, according to two non-zero base voltage vectors a PWM period T _sInterior action time t ₁, t ₂With the actual Dead Time T of voltage source inverter _dCarry out the time bias in dead band.This dead band make-up time t _Com1, t _Com2Simultaneously to two non-zero base voltage vector t action time ₁, t ₂Compensate.

Described two dead area compensation time t _Com1, t _Com2For

Described two dead area compensation time t _Com1, t _Com2Be added to two non-zero base voltage vector t action time respectively ₁, t ₂On, obtain two t action time that non-zero base voltage vector is new ₁₁, t ₂₂

By described two t action time that non-zero base voltage vector is new ₁₁, t ₂₂Proceed the computing of SVPWM modulation strategy, generate needed pwm pulse, realize that finally dead area compensation and zero current clamp effect suppress.

The operating procedure of dead-zone compensation method that the present invention is used for voltage source inverter is as follows:

(1) obtains the Dead Time T of voltage source inverter by the method for off-line test or online observation _d

(2) according to the operation method of traditional SVPWM modulation strategy, by two shaft voltage u under the two-phase static coordinate _α, u _β, try to achieve its synthesized voltage vector V _RefThe sector at place, and calculate and this voltage vector V _RefA PWM period T _sT action time of two non-zero base voltage vectors of this sector of interior action effect equivalence ₁, t ₂

(3) according to two non-zero base voltage vector t action time that tried to achieve ₁, t ₂, and the actual Dead Time T of voltage source inverter _d, try to achieve dead area compensation time t according to formula (1) _Com1, t _Com2:

$\left\{\begin{array}{c}{t}_{\mathrm{<figure-callout\; id="1"\; label="com"\; filenames="HSA00000160733600021.png,HSA00000160733600022.png"\; state="\{\{state\}\}">com</figure-callout>}1}=\frac{2t_1{\mathrm{<figure-callout\; id="1"\; label="T\; d\; t"\; filenames="HSA00000160733600021.png,HSA00000160733600022.png"\; state="\{\{state\}\}">T</figure-callout>}}_d}{t_{}}\\ {\mathrm{<figure-callout\; id="2"\; label="t\; com"\; filenames="HSA00000160733600011.png,HSA00000160733600022.png"\; state="\{\{state\}\}">t</figure-callout>}}_{\mathrm{com}}=\frac{2t_2{\mathrm{<figure-callout\; id="1"\; label="T\; d\; t"\; filenames="HSA00000160733600021.png,HSA00000160733600022.png"\; state="\{\{state\}\}">T</figure-callout>}}_d}{t_{}}\end{array}\right.---\left(1\right)$

(4) by formula (2) with the dead area compensation time t that tries to achieve _Com1, t _Com2Respectively with two non-zero base voltage vector t action time ₁, t ₂New t action time of two non-zero base voltage vectors in this sector is tried to achieve in addition ₁₁, t ₂₂

$\left\{\begin{array}{c}{\mathrm{<figure-callout\; id="11"\; label="t"\; filenames="HSA00000160733600023.png"\; state="\{\{state\}\}">t</figure-callout>}}_{11}={\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HSA00000160733600021.png,HSA00000160733600022.png"\; state="\{\{state\}\}">t</figure-callout>}}_1+t_{\mathrm{com}1}\\ t_{22}={\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HSA00000160733600011.png,HSA00000160733600022.png"\; state="\{\{state\}\}">t</figure-callout>}}_2+t_{\mathrm{com}2}\end{array}\right.---\left(2\right)$

(5) with new t action time of two non-zero base voltage vectors ₁₁, t ₂₂Proceed the computing of SVPWM modulation strategy, finally obtain pwm pulse.

Cardinal principle of the present invention is as follows:

The main cause that zero current clamp effect produces is: voltage source inverter is under the situation with low electric frequency operation, at certain phase current near zero the time, owing to the dead band reason of voltage source inverter cause two the non-zero base voltage vector action times of a PWM in the cycle all less than 2 times of Dead Times, thereby make that these two non-zero base voltage vectors practical function effect in this cycle is zero, also just cause actual this phase voltage that goes up mutually that is added in to equal this phase back electromotive force, make that finally this phase current is zero always.Have only in these two non-zero base voltage vectors one a PWM in the cycle action time could be again greater than the Dead Time of twice set up effective phase voltage on mutually at this, just can make this phase current withdraw from zero clamp district.Therefore for reducing the number of times of two base voltage vector whiles action time less than 2 times of Dead Times to greatest extent, the present invention compensated the time in the dead band of voltage source inverter, had also realized suppressing the purpose of zero current clamp effect simultaneously.

Description of drawings

The system configuration schematic diagram of Fig. 1 voltage source inverter band permagnetic synchronous motor during as load;

Fig. 2 dead-zone compensation method schematic diagram of the present invention;

Fig. 3 SVPWM modulation strategy schematic diagram;

Fig. 4 a does not carry out the phase current waveform of dead area compensation; Fig. 4 b current spectrum;

Fig. 5 a uses the phase current waveform of the inventive method; Fig. 5 b current spectrum.

Embodiment

Further specify the present invention below in conjunction with the drawings and specific embodiments.

Permanent magnet synchronous motor vector control system with the voltage source inverter power supply is an example, and dead-zone compensation method of the present invention is described, Fig. 1 is this system configuration schematic diagram.As shown in Figure 1, this voltage source inverter is made up of parts such as power model, current sensor and dsp controllers.The power model of voltage source inverter is the FF600R06ME3 of Infineon among Fig. 1; The permagnetic synchronous motor parameter: rated power is 20kW, and rated speed is 2500rpm, and number of pole-pairs is 3, and the stator phase resistance is 26m Ω, and d axle inductance is 0.52mH, and q axle inductance is 1.02mH, and the permanent magnetism magnetic linkage is 0.129Wb.The detecting apparatus for rotor position that is installed on the motor detects motor rotor position.Set busbar voltage 330V in the experiment, motor speed 300rpm, load is 10Nm, artificially sets Dead Time 3.2 μ s, the actual Dead Time that records is 3.84 μ s.

(1) first step as shown in Figure 1, is given dsp controller with the current signal of current sensor collection and the rotor-position signal of detecting apparatus for rotor position acquisition, and dsp controller calculates d-q axle command voltage u according to current signal under synchronous rotating frame _d, u _q, then the anti-PARK conversion of this command voltage is obtained alpha-beta shaft voltage u under the two-phase rest frame _α, u _β, as shown in Figure 2.

(2) second steps are with alpha-beta shaft voltage u _α, u _βSend into and carry out computing, at first synthesized voltage vector V in the SVPWM modulation strategy _RefSuppose this voltage vector V _RefBe positioned at the 3rd sector, as shown in Figure 3.According to formula (1), in the 3rd sector with two non-zero base voltage vector V _{4 (100)}, V _{6 (110)}A PWM period T _sInterior action time t ₁, t ₂Come equivalent V _RefAct on a PWM period T _sObtain V according to formula (2) _{4 (100)}, V _{6 (110)}In this PWM period T _sInterior action time t ₁, t ₂

$\left\{\begin{array}{c}{V}_{\mathrm{ref}}{T}_s=V_{4\left(100\right)}{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HSA00000160733600021.png,HSA00000160733600022.png"\; state="\{\{state\}\}">t</figure-callout>}}_1+V_{6\left(110\right)}{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HSA00000160733600011.png,HSA00000160733600022.png"\; state="\{\{state\}\}">t</figure-callout>}}_2\\ \left|V_{4\left(100\right)}\right|=\left|V_{6\left(110\right)}\right|=\frac{2}{3}{V}_{\mathrm{dc}}\end{array}\right.---\left(1\right)$

$\left\{\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HSA00000160733600021.png,HSA00000160733600022.png"\; state="\{\{state\}\}">t</figure-callout>}}_1=\frac{T_s}{2V_{\mathrm{dc}}}(3V_{\mathrm{\&alpha;}}-\sqrt{3}{V}_{\mathrm{\&beta;}})\\ {\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HSA00000160733600011.png,HSA00000160733600022.png"\; state="\{\{state\}\}">t</figure-callout>}}_2=\frac{\sqrt{3}{T}_s}{V_{\mathrm{dc}}}{V}_{\mathrm{\&beta;}}\end{array}\right.---\left(2\right)$

(3) the 3rd steps are according to algorithm principle shown in Figure 2, according to the base voltage vector V of trying to achieve _{4 (100)}, V _{6 (110)}A PWM period T _sInterior action time t ₁, t ₂, try to achieve dead area compensation time t by formula (3) _Com1, t _Com2

$\left\{\begin{array}{c}{t}_{\mathrm{<figure-callout\; id="1"\; label="com"\; filenames="HSA00000160733600021.png,HSA00000160733600022.png"\; state="\{\{state\}\}">com</figure-callout>}1}=\frac{2t_1{\mathrm{<figure-callout\; id="1"\; label="T\; d\; t"\; filenames="HSA00000160733600021.png,HSA00000160733600022.png"\; state="\{\{state\}\}">T</figure-callout>}}_d}{t_{}}\\ {\mathrm{<figure-callout\; id="2"\; label="t\; com"\; filenames="HSA00000160733600011.png,HSA00000160733600022.png"\; state="\{\{state\}\}">t</figure-callout>}}_{\mathrm{com}}=\frac{2t_2{\mathrm{<figure-callout\; id="1"\; label="T\; d\; t"\; filenames="HSA00000160733600021.png,HSA00000160733600022.png"\; state="\{\{state\}\}">T</figure-callout>}}_d}{t_{}}\end{array}\right.---\left(3\right)$

In the formula: T _dDead Time for voltage source inverter.

In (4) the 4th steps, try to achieve the base voltage vector V by formula (4) _{4 (100)}, V _{6 (110)}In this PWM period T _sInterior new t action time ₁₁, t ₂₂

$\left\{\begin{array}{c}{\mathrm{<figure-callout\; id="11"\; label="t"\; filenames="HSA00000160733600023.png"\; state="\{\{state\}\}">t</figure-callout>}}_{11}={\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HSA00000160733600021.png,HSA00000160733600022.png"\; state="\{\{state\}\}">t</figure-callout>}}_1+t_{\mathrm{com}1}\\ t_{22}={\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HSA00000160733600011.png,HSA00000160733600022.png"\; state="\{\{state\}\}">t</figure-callout>}}_2+t_{\mathrm{com}2}\end{array}\right.---\left(4\right)$

(5) the 5th steps are by the new time t that tries to achieve ₁₁, t ₂₂Continue to participate in the computing of SVPWM modulation strategy, calculate the zero-time that each power device of the last brachium pontis of voltage source inverter is opened, assign it to the COMPARE comparator in the dsp controller, generate 6 road pwm pulses according to formula (5).

$\left\{\begin{array}{c}{t}_{\mathrm{aon}}=\frac{T_s-t_1-{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HSA00000160733600011.png,HSA00000160733600022.png"\; state="\{\{state\}\}">t</figure-callout>}}_2}{4}\\ t_{\mathrm{bon}}=t_{\mathrm{aon}}+\frac{{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HSA00000160733600021.png,HSA00000160733600022.png"\; state="\{\{state\}\}">t</figure-callout>}}_1}{2}\\ t_{\mathrm{con}}=t_{\mathrm{bon}}+\frac{{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HSA00000160733600011.png,HSA00000160733600022.png"\; state="\{\{state\}\}">t</figure-callout>}}_2}{2}\end{array}\right.---\left(5\right)$

In the formula: t _Aon, t _Bon, t _ConThree of the last brachium pontis of corresponding voltage source inventer zero-times that power device is successively opened respectively.Synthetic voltage vector is still adopted the realization dead-time compensation that uses the same method in other sector, as shown in Figure 2.

Figure 5 shows that the experimental result that draws according to above-mentioned steps.Fig. 4 a is that the phase current waveform, Fig. 4 b that do not carry out dead area compensation are its current spectrums, Fig. 5 a is that phase current waveform, Fig. 5 b behind employing the present invention is current spectrum, comparison diagram 4 and Fig. 5, find that current waveform sine degree obviously improves, total percent harmonic distortion drops to 3.2921% from 8.2541%, and zero current clamp effect has obtained inhibition.

Thus, the present invention has suppressed zero current clamp effect effectively, has improved the sinusoidal degree of phase current waveform significantly, has greatly weakened the low-frequency current harmonic wave, has improved system's low cruise performance significantly.

Claims (2)

1. a dead-zone compensation method that is used for voltage source inverter is characterized in that, described compensatory approach is on the basis of traditional SVPWM modulation strategy, according to two non-zero base voltage vectors a PWM period T _sInterior action time t ₁, t ₂With the actual Dead Time T of voltage source inverter _dCarry out the time bias in dead band; This dead band make-up time t _Com1, t _Com2Simultaneously to two non-zero base voltage vector t action time ₁, t ₂Compensate.

2. the dead-zone compensation method of voltage source inverter according to claim 1 is characterized in that,

Described two dead area compensation times

With described two dead area compensation time t _Com1, t _Com2Respectively with two non-zero base voltage vector t action time ₁, t ₂Addition is tried to achieve two non-zero base voltage vectors at this PWM new t action time in the cycle ₁₁, t ₂₂:

With described two t action time that non-zero base voltage vector is new ₁₁, t ₂₂Proceed the computing of SVPWM modulation strategy, generate needed pwm pulse, realize that finally dead area compensation and zero current clamp effect suppress.

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