CN104852657A - Control method for suppressing current zero-crossing fluctuation of bus-shared single-side controllable open-winding permanent-magnet motor system - Google Patents

Abstract

The invention discloses a control method for suppressing current zero-crossing fluctuation of a bus-shared single-side controllable open-winding permanent-magnet motor system. The motor system employs a common-direct-current power supply structure. A proper zero-sequence current reference value is designed and a proportional resonance controller is used to achieve an objective rapid zero crossing of the current. The system employs a full-control converter and an uncontrolled converter, so that the cost is reduced and the system capacity is increased; only one direct-current power supply is involved in the system and no isolation is needed, thereby realizing rapid zero crossing of the current. Only the control algorithm us changed and no system hardware cost needs to be increased. Compared with the traditional control method, the current zero-crossing fluctuation is reduced; the number of times of switching of the power diode is reduced; and the system EMI is also reduced. The control method is simple; and the anti-interference capability is high.

Description

A kind of suppress common bus monolateral controlled open winding permanent magnet motor system power zero crossing fluctuation control method

Technical field

The invention belongs to motor control technology field, be specifically related to a kind of suppress common bus monolateral controlled open winding permanent magnet motor system power zero crossing fluctuation control method.

Background technology

Wind energy, as a kind of clean regenerative resource, is subject to the great attention of countries in the world in recent years.Wind energy reserves are huge, and the wind power generation in the whole world keeps fast for years, lasting growth.Due to the appearance of the permanent magnetic material of aluminium nickel cobalt, ferrite and the contour magnetic energy density of neodymium iron boron, magneto is made to obtain unprecedented development and growth.The advantages such as permanent magnet direct-driven Wind turbines is high with its reliability, structure is simple, maintenance cost is low, grid-connected strong adaptability, progressively develop into the mainstream model in each large wind energy turbine set.

For traditional permanent-magnet synchronous wind power system structure, need the normal operation of flat-out current transformer guarantee system.In recent years, open winding electric machine structure to be suggested to reduce switching tube stress (as shown in Figure 1).Connect winding neutral point by traditional Y to untie, winding two ends respectively connect a current transformer, by the control of two current transformers to realize the conversion of energy.Meanwhile, open winding construction system and can realize three-level control principle, be of value to the electric pressure that improve motor, and reduce the harmonic content of voltage modulated.

But opening in the middle of the electric machine control system of winding construction, controller needs to carry out switch control rule to more switching device, increases the complexity of control system on the one hand, has had higher requirement on the other hand to control signal real-time.For reducing the complexity opening winding electric machine system, a kind of monolateral controlled winding electric machine system of opening is suggested (as shown in Figure 2), namely adopts one group of diode rectifier bridge and one group of voltage converter to be connected to out winding electric machine two ends.Because this topological gate-controlled switch number of devices is the half that tradition opens winding PMSG system, thus decrease the complexity of Systematical control.

But monolaterally controlledly open for winding electric machine system for this, when common DC bus, current harmonics can increase along with the increase of power-factor angle.When there is certain power-factor angle, every phase current can fluctuate a period of time to keep the identical polar with voltage at zero crossing.This zero crossing wave phenomenon, that can cause diode constantly opens shutoff, and this can increase the switching loss of diode to a certain extent, also can bring very large electromagnetic interference (EMI) to whole system.

Summary of the invention

For the above-mentioned technical problem existing for prior art, the invention provides a kind of suppress common bus monolateral controlled open winding permanent magnet motor system power zero crossing fluctuation control method, the zero crossing of electric current can be effectively suppressed to fluctuate, reduce switching loss and system EMI, structure is simple, cost is low, and antijamming capability is strong.

Suppress the monolateral controlled control method opening the fluctuation of winding permanent magnet motor system power zero crossing of common bus, comprise the steps:

(1) terminal voltage of described permanent magnet motor system, phase current, public DC bus-bar voltage U is gathered _dc, motor speed ω and rotor position angle θ;

(2) the rotor position angle θ described in utilization carries out dq0 Rotating Transition of Coordinate to phase current, obtains the d axle component i of phase current _d, q axle component i _qwith 0 axle component i _z;

(3) according to the d axle component i of described motor speed ω and phase current _d, q axle component i _qwith 0 axle component i _z, calculate the real output P of permanent magnet motor system, meritorious shaft voltage compensation rate Δ u _q, idle shaft voltage compensation rate Δ u _dwith residual voltage compensation rate Δ u _z;

(4) according to described real output P, meritorious shaft voltage compensation rate Δ u _qwith idle shaft voltage compensation rate Δ u _d, by being that the vector control algorithm of zero calculates meritorious shaft voltage instruction u based on idle shaft current _qwith idle shaft voltage instruction u _d;

(5) according to described meritorious shaft voltage instruction u _qwith idle shaft voltage instruction u _dcalculate zero-sequence current reference value I _z; And then according to described zero-sequence current reference value I _zwith 0 axle component i _zpassing ratio resonance controls, and calculates residual voltage instruction u _z;

(6) according to the phase voltage not controlling type AC side of converter in described phase current determination permanent magnet motor system, and dq0 Rotating Transition of Coordinate is carried out to described phase voltage, obtain the d axle component u of phase voltage _d2, q axle component u _q2with 0 axle component u _z2; And then make described d axle component u _d2, q axle component u _q2with 0 axle component u _z2corresponding and idle shaft voltage instruction u _d, meritorious shaft voltage instruction u _qwith residual voltage instruction u _zbe added, obtain the idle shaft voltage instruction u of controllable type current transformer in permanent magnet motor system _d1, meritorious shaft voltage instruction u _q1with residual voltage instruction u _z1;

(7) according to described idle shaft voltage instruction u _d1with meritorious shaft voltage instruction u _q1, utilize SVPWM (space voltage vector modulation) algorithm to determine the effect duration of corresponding two the effective vectors in sector and this sector at the modulation voltage vector place of described controllable type current transformer; And then according to described residual voltage instruction u _z1with DC bus-bar voltage U _dc, calculate the effect duration of controllable type current transformer two zero vectors;

According to described two effective vectors and the effect duration of correspondence thereof and the effect duration of two zero vectors and correspondence thereof, structure obtains one group of pwm signal to control controllable type current transformer.

The real output P of permanent magnet motor system, meritorious shaft voltage compensation rate Δ u is calculated according to following formula in described step (3) _q, idle shaft voltage compensation rate Δ u _dΔ u is compensated with residual voltage _z;

$P=\frac{3}{2}\mathrm{\ω}[L_q{i}_q{i}_d+({\mathrm{\ψ}}_r-L_d{i}_d)i_q-6{\mathrm{\ψ}}_{3r}\sin \left(3\mathrm{\θ}\right)i_0]$

$\left\{\begin{array}{c}\mathrm{\Δ}{u}_d=\mathrm{\ω}{L}_q{i}_q\\ \mathrm{\Δ}{u}_q=\mathrm{\ω}{\mathrm{\Ψ}}_r-\mathrm{\ω}{L}_d{i}_d\\ \mathrm{\Δ}{u}_z=-3\mathrm{\ω}{\mathrm{\ψ}}_{3r}\sin 3\mathrm{\θ}\end{array}\right.$

Wherein: L _dand L _qbe respectively d-axis inductance and the quadrature axis inductance of magneto, Ψ _rand Ψ _3rbe respectively fundametal compoment and the third-harmonic component of permanent magnet machine rotor magnetic linkage.

Be the vector control algorithm of zero based on idle shaft current in described step (4), detailed process is as follows:

4.1 make the target output P preset _refdeduct described real output P, obtain power error P _err;

Power error P described in 4.2 couples _errcarry out PI (proportional integral) adjustment and obtain meritorious shaft current instruction I _q, with seasonal idle shaft current instruction I _dbe zero;

4.3 make idle shaft current instruction I _dwith meritorious shaft current instruction I _qdeduct the d axle component i of phase current respectively _dwith q axle component i _q, obtain idle shaft current error i _derrwith meritorious shaft current error i _qerr;

4.4 respectively to described meritorious shaft current error i _qerrwith idle shaft current error i _derrcarry out PI adjustment and obtain meritorious shaft voltage error u _qerrwith idle shaft voltage error u _derr; Make described meritorious shaft voltage compensation rate Δ u _qwith idle shaft voltage compensation rate Δ u _ddeduct meritorious shaft voltage error u respectively _qerrwith idle shaft voltage error u _derr, namely obtain meritorious shaft voltage instruction u _qwith idle shaft voltage instruction u _d.

Zero-sequence current reference value I is calculated by following formula in described step (5) _z:

The concrete computational process that in described step (5), ratio resonance controls is as follows:

First, described zero-sequence current instruction I is made _zdeduct 0 axle component i of phase current _z, obtain zero-sequence current error i _zerr;

Then, to described zero-sequence current error i _zerrcarry out PR (ratio resonance) adjustment and obtain residual voltage error u _zerr;

Finally, described residual voltage compensation rate Δ u is made _zdeduct residual voltage error u _zerr, namely obtain residual voltage instruction u _z.

By not controlling the phase voltage of type AC side of converter in following relational expression determination permanent magnet motor system in described step (6):

$\left\{\begin{array}{c}{u}_{a2}=\left\{\begin{array}{cc}{U}_{\mathrm{dc}},& \mathrm{if}(i_a<0)\\ 0,& \mathrm{if}(i_a\&GreaterEqual;0)\end{array}\right.\\ u_{b2}=\begin{array}{}\end{array}\begin{array}{}\end{array}\left\{\begin{array}{cc}{U}_{\mathrm{dc}},& \mathrm{if}(i_b<0)\\ 0,& \mathrm{if}(i_b\&GreaterEqual;0)\end{array}\right.\\ u_{c2}=\left\{\begin{array}{cc}{U}_{\mathrm{dc}},& \mathrm{if}(i_c<0)\\ 0,& \mathrm{if}(i_c\&GreaterEqual;0)\end{array}\right.\end{array}\right.$

Wherein: u _a2~ u _c2be respectively A phase voltage, B phase voltage and the C phase voltage of not controlling type AC side of converter, i _a~ i _cbe respectively the A phase current of permanent magnet motor system, B phase current and C phase current.

According to described residual voltage instruction u in described step (7) _z1with DC bus-bar voltage U _dc, the effect duration of controllable type current transformer two zero vectors is calculated by following rule;

When the modulation voltage vector of controllable type current transformer is positioned at the first sector, two effective vectors corresponding to this sector are respectively 100 and 110; Now, the effect duration of controllable type current transformer two zero vectors is calculated by following formula:

$T_{111}=\frac{u_{z1}}{U_{\mathrm{dc}}}{T}_s-\frac{1}{3}{T}_{100}-\frac{2}{3}{T}_{110}$

T ₀₀₀＝T _s-T ₁₀₀-T ₁₁₀-T ₁₁₁

When the modulation voltage vector of controllable type current transformer is positioned at the second sector, two effective vectors corresponding to this sector are respectively 010 and 110; Now, the effect duration of controllable type current transformer two zero vectors is calculated by following formula:

$T_{111}=\frac{u_{z1}}{U_{\mathrm{dc}}}{T}_s-\frac{1}{3}{T}_{010}-\frac{2}{3}{T}_{110}$

T ₀₀₀＝T _s-T ₀₁₀-T ₁₁₀-T ₁₁₁

When the modulation voltage vector of controllable type current transformer is positioned at the 3rd sector, two effective vectors corresponding to this sector are respectively 010 and 011; Now, the effect duration of controllable type current transformer two zero vectors is calculated by following formula:

$T_{111}=\frac{u_{z1}}{U_{\mathrm{dc}}}{T}_s-\frac{1}{3}{T}_{010}-\frac{2}{3}{T}_{011}$

T ₀₀₀＝T _s-T ₀₁₀-T ₀₁₁-T ₁₁₁

When the modulation voltage vector of controllable type current transformer is positioned at the 4th sector, two effective vectors corresponding to this sector are respectively 001 and 011; Now, the effect duration of controllable type current transformer two zero vectors is calculated by following formula:

$T_{111}=\frac{u_{z1}}{U_{\mathrm{dc}}}{T}_s-\frac{1}{3}{T}_{001}-\frac{2}{3}{T}_{011}$

T ₀₀₀＝T _s-T ₀₀₁-T ₀₁₁-T ₁₁₁

When the modulation voltage vector of controllable type current transformer is positioned at the 5th sector, two effective vectors corresponding to this sector are respectively 001 and 101; Now, the effect duration of controllable type current transformer two zero vectors is calculated by following formula:

$T_{111}=\frac{u_{z1}}{U_{\mathrm{dc}}}{T}_s-\frac{1}{3}{T}_{001}-\frac{2}{3}{T}_{101}$

T ₀₀₀＝T _s-T ₀₀₁-T ₁₀₁-T ₁₁₁

When the modulation voltage vector of controllable type current transformer is positioned at the 6th sector, two effective vectors corresponding to this sector are respectively 100 and 101; Now, the effect duration of controllable type current transformer two zero vectors is calculated by following formula:

$T_{111}=\frac{u_{z1}}{U_{\mathrm{dc}}}{T}_s-\frac{1}{3}{T}_{100}-\frac{2}{3}{T}_{101}$

T ₀₀₀＝T _s-T ₁₀₀-T ₁₀₁-T ₁₁₁

Wherein: T _sfor the switch periods of device for power switching in current transformer, T ₁₁₁and T ₀₀₀be respectively the effect duration of controllable type current transformer two zero vectors 111 and 000 correspondence, T ₁₀₀, T ₀₁₁, T ₁₁₀, T ₀₀₁, T ₁₀₁and T ₀₁₀be respectively the effect duration of six, controllable type current transformer effective vector 100,011,110,001,101 and 010 correspondence.

The present invention is based on the monolateral controlled magneto opening winding construction, adopt DC power supply structure altogether, by designing suitable zero-sequence current reference value, and adoption rate resonant controller reaches the object of the quick zero passage of electric current; Present system adopt one full control current transformer and one do not control current transformer, add the capacity of system while reducing cost, and only relate to a DC power supply and do not need isolation, realize the quick zero passage of electric current.Just change in control algolithm, do not need to increase system hardware cost.Compared to traditional control method, present invention decreases current zero-crossing point fluctuation, reduce the on-off times of power diode, reduce the EMI of system, control method is simple, and antijamming capability is strong.

Accompanying drawing explanation

Fig. 1 is the structural representation that tradition opens winding permanent magnet motor system.

Fig. 2 the present invention is based on the structural representation that monolateral controlled common DC bus opens winding permanent magnet motor system.

Fig. 3 is the control flow chart that the present invention realizes the quick zero passage of electric current.

Fig. 4 is the control block diagram of zero-sequence current component passing ratio resonant controller.

Fig. 5 (a) opens the oscillogram of winding electric machine a phase current under the quick Super-zero control method of no current for the monolateral controlled common DC bus of the present invention.

Fig. 5 (b) for the monolateral controlled common DC bus of the present invention open winding electric machine under the quick Super-zero control method of no current diode rectifier bridge at the copped wave output waveform figure of current zero-crossing point.

Fig. 6 (a) opens winding electric machine in the oscillogram adopting a phase current under electric current quick Super-zero control method for the monolateral controlled common DC bus of the present invention.

Fig. 6 (b) opens winding electric machine for the monolateral controlled common DC bus of the present invention and to adopt under electric current quick Super-zero control method diode rectifier bridge at the copped wave output waveform figure of current zero-crossing point.

Embodiment

In order to more specifically describe the present invention, below in conjunction with the drawings and the specific embodiments, technical scheme of the present invention is described in detail.

As shown in Figure 2, the present invention is based on monolateral controlled common DC bus and open winding permanent magnet motor system, comprising: magneto, full-control type current transformer J1, one do not control type current transformer J2, an a DC power supply S and controller; Wherein, magneto has three-phase windings, and for opening winding construction; Current transformer J1 adopts the controlled full-bridge rectifier of three-phase, current transformer J2 adopts three-phase not control full-bridge rectifier, current transformer J1 and J2 DC side share same DC power supply, and DC power supply there is a bus capacitor C, each brachium pontis is at least made up of an electronic power switch devices in series, in present embodiment, full control switching device adopts IGBT, does not control switching device and adopts diode; One end of the arbitrary phase winding of magneto is connected with the central contact of corresponding phase upper and lower bridge arm in full-control type current transformer J1, and the other end is connected with the central contact not controlling corresponding phase upper and lower bridge arm in type current transformer J2.

Controller is for gathering the terminal voltage u of permagnetic synchronous motor _a~ u _c, phase current i _a~ i _c, two DC bus-bar voltage U that current transformer is public _dcand the rotating speed that exports of coding disk and position signalling, and then construct pwm signal to control current transformer J1 by control strategy.In present embodiment, controller adopts DSP.

As shown in Figure 3, the suppressing method of above-mentioned electric system zero-sequence current, comprises the steps:

(1) the terminal voltage u of magneto is gathered _a~ u _c, phase current i _a~ i _c, the VD U that two current transformers are public _dcand coding disk export rotational speed omega and position signalling θ.

(2) utilize rotor position angle θ to carry out dq0 conversion to phase current, obtain the d axle component i of phase current _d, q axle component i _qand zero-sequence component i _z:

$\left[\begin{array}{c}{i}_d\\ i_q\\ i_z\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}\cos \mathrm{\&theta;}& \cos (\mathrm{\&theta;}-\frac{2}{3}\mathrm{\&pi;})& \cos (\mathrm{\&theta;}+\frac{2}{3}\mathrm{\&pi;})\\ -\sin \mathrm{\&theta;}& -\sin (\mathrm{\&theta;}-\frac{2}{3}\mathrm{\&pi;})& -\sin (\mathrm{\&theta;}+\frac{2}{3}\mathrm{\&pi;})\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]\left[\begin{array}{c}{i}_a\\ i_b\\ i_c\end{array}\right]$

(3) according to the d axle component i of rotational speed omega and phase current _d, q axle component i _qwith zero-sequence component i _z, calculate the real output P of magneto, meritorious shaft voltage compensation rate Δ u according to following formula _q, idle shaft voltage compensation rate Δ u _dwith residual voltage compensation rate Δ u _z;

$P=\frac{3}{2}\mathrm{\&omega;}[L_q{i}_q{i}_d+({\mathrm{\&psi;}}_r-L_d{i}_d)i_q-6{\mathrm{\&psi;}}_{3r}\sin \left(3\mathrm{\&theta;}\right)i_z]$

$\left\{\begin{array}{c}\mathrm{\&Delta;}{u}_d=\mathrm{\&omega;}{L}_q{i}_q\\ \mathrm{\&Delta;}{u}_q=\mathrm{\&omega;}{\mathrm{\&Psi;}}_r-\mathrm{\&omega;}{L}_d{i}_d\\ \mathrm{\&Delta;}{u}_z=-3\mathrm{\&omega;}{\mathrm{\&psi;}}_{3r}\sin 3\mathrm{\&theta;}\end{array}\right.$

Wherein: ω is the electromagnetism rotating speed of magneto, and θ is the rotor position angle of magneto, L _dand L _qbe respectively d-axis inductance and the quadrature axis inductance of magneto, Ψ _rfor the rotor flux fundametal compoment of magneto, Ψ _3rfor the rotor flux third-harmonic component of magneto; In present embodiment, Ψ _r=2.802V.s, Ψ _3r=0.064V.s, L _d=77.56mH, L _q=107.4mH.

And then the meritorious shaft voltage instruction u of motor is calculated according to the vector control algorithm based on idle shaft current being zero _qwith idle shaft voltage instruction u _d;

3.1 make goal-selling power output P _refdeduct real output P, obtain power error P _err; P in present embodiment _ref=1000W;

3.2 carry out PI adjustment according to following formula to power error Δ P obtains meritorious shaft current instruction I _q, and make idle shaft current instruction I _dbe 0;

$I_q=(K_{p1}+\frac{K_{i1}}{s})P_{\mathrm{err}}$

Wherein, K _p1and K _i1be respectively proportionality coefficient and integral coefficient, s is Laplacian; In present embodiment, K _p1=0.5, K _i1=0.005.

3.3 make idle shaft current instruction I _dwith meritorious shaft current instruction I _qdeduct the d axle component i of phase current respectively _dwith q axle component i _q, obtain idle shaft current error i _derrwith meritorious shaft current error i _qerr;

3.4 according to following formula respectively to meritorious shaft current error i _qerrwith idle shaft current error i _derrcarry out PI adjustment and obtain meritorious shaft voltage error and idle shaft voltage error, make meritorious shaft voltage compensation rate Δ u _qwith idle shaft voltage compensation rate Δ u _ddeduct meritorious shaft voltage error and idle shaft voltage error respectively, namely obtain the meritorious shaft voltage instruction u of motor _qwith idle shaft voltage instruction u _d;

$u_q=\mathrm{\&Delta;}{u}_q-(K_{p2}+\frac{K_{i2}}{s})i_{\mathrm{qerr}}$

$u_d=\mathrm{\&Delta;}{u}_b-(K_{p2}+\frac{K_{i2}}{s})i_{\mathrm{derr}}$

Wherein, K _p2and K _i2be respectively proportionality coefficient and integral coefficient, in present embodiment, K _p2=5, K _i2=0.08.

3.5 according to the idle shaft current instruction I tried to achieve _d, meritorious shaft current instruction I _q, idle shaft voltage instruction u _d, meritorious shaft voltage instruction u _q, obtain residual voltage reference instruction I _z;

Wherein: for the position angle of current phasor, for the position angle of voltage vector, for the phase angle difference of voltage vector and current phasor.

Make zero-sequence current instruction I _zdeduct the zero-sequence component i of phase current _z, obtain zero-sequence current error i _zerr;

3.6 as shown in Figure 4, according to following formula respectively to zero-sequence current error i _zerrcarry out PR adjustment and obtain residual voltage error u _zerr, make residual voltage compensation rate Δ u _zdeduct residual voltage error u _zerr, namely obtain the residual voltage instruction u of motor _z;

Wherein, K _p3and K _rbe respectively proportionality coefficient and resonance coefficient, ω _cfor cut-off frequency, in present embodiment, K _p3=5, K _r=0.1, ω _c=2rad/s, ω _c=3 ω.

(4) according to the phase current i of motor _a~ i _c, determine the size u not controlling type current transformer J2 AC three-phase voltage _a2, u _b2, u _c2:

$\left\{\begin{array}{c}{u}_{a2}=\left\{\begin{array}{c}{U}_{\mathrm{dc}},\mathrm{if}(i_a<0)\\ 0,\mathrm{if}(i_a>0)\end{array}\right\}\\ u_{b2}=\left\{\begin{array}{c}{U}_{\mathrm{dc}},\mathrm{if}(i_b<0)\\ 0,\mathrm{if}(i_b>0)\end{array}\right\}\\ u_{c2}=\left\{\begin{array}{c}{U}_{\mathrm{dc}},\mathrm{if}(i_c<0)\\ 0,\mathrm{if}(i>0)\end{array}\right\}\end{array}\right.$

Wherein: the direction that stator current flows to current transformer J1 from current transformer J2 is just, otherwise is negative; U _dcit is the public DC bus-bar voltage of two current transformers;

And then utilize rotor position angle θ to the three-phase voltage u of current transformer J2 AC _a2, u _b2, u _c2carry out dq0 conversion, obtain the meritorious shaft voltage u of current transformer J2 _q2, idle shaft voltage u _d2with residual voltage u _z2;

$\left[\begin{array}{c}{u}_{d2}\\ u_{q2}\\ u_{z2}\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}\cos \mathrm{\&theta;}& \cos (\mathrm{\&theta;}-\frac{2}{3}\mathrm{\&pi;})& \cos (\mathrm{\&theta;}+\frac{2}{3}\mathrm{\&pi;})\\ -\sin \mathrm{\&theta;}& -\sin (\mathrm{\&theta;}-\frac{2}{3}\mathrm{\&pi;})& -\sin (\mathrm{\&theta;}+\frac{2}{3}\mathrm{\&pi;})\\ \frac{1}{2}& \frac{1}{2}& \frac{1}{2}\end{array}\right]\left[\begin{array}{c}{u}_{a2}\\ u_{b2}\\ u_{c2}\end{array}\right]$

The meritorious shaft voltage instruction u will obtained in step (3) again _q, idle shaft voltage instruction u _dwith residual voltage instruction u _zthe meritorious shaft voltage u of correspondence and current transformer J2 _q2, idle shaft voltage u _d2with residual voltage instruction u _z2be added the meritorious shaft voltage instruction u obtaining current transformer J1 _q1, idle shaft voltage instruction u _d1with residual voltage instruction u _z1.

$\left\{\begin{array}{c}{u}_{d1}=u_d+d_{d2}\\ u_{q1}=u_q+u_{q2}\\ u_{z1}=u_2+u_{z2}\end{array}\right.$

(5) SVPWM modulation system traditionally, according to rotor position angle θ, u _d1and u _q1judge the modulation voltage instruction u of current transformer J1 ₁=(u _d1+ u _q1j) sector, place, selects suitable effective vectorial combination, and calculates the effective vector action time of current transformer J1 in real time.For current transformer J1, as modulation voltage instruction u ₁when being positioned at different sector, effective vector 100,110,010,011, the action time of 001,101 is denoted as T respectively ₁₀₀, T ₁₁₀, T ₀₁₀, T ₀₁₁, T ₀₀₁, T ₁₀₁.

According to the effective vector action time of current transformer J1, residual voltage instruction u _z, DC bus-bar voltage U _dc, calculate a switch periods T _st action time of the Zero voltage vector 000 and 111 of interior current transformer 1 ₀₀₀, T ₁₁₁.Its specific implementation is as follows:

Work as u ₁when being positioned at sector 1, effective vector is 100 and 110; Now, be respectively the action time of Zero voltage vector 000 and 111:

$T_{111}=\frac{u_{z1}}{U_{\mathrm{dc}}}{T}_s-\frac{1}{3}{T}_{100}-\frac{2}{3}{T}_{110}$

T ₀₀₀＝T _s-T ₁₀₀-T ₁₁₀-T ₁₁₁

Work as u ₁when being positioned at sector 2, effective vector is 010 and 110; Now, be respectively the action time of Zero voltage vector 000 and 111:

$T_{111}=\frac{u_{z1}}{U_{\mathrm{dc}}}{T}_s-\frac{1}{3}{T}_{010}-\frac{2}{3}{T}_{110}$

T ₀₀₀＝T _s-T ₀₁₀-T ₁₁₀-T ₁₁₁

Work as u ₁when being positioned at sector 3, effective vector is 010 and 011; Now, be respectively the action time of Zero voltage vector 000 and 111:

$T_{111}=\frac{u_{z1}}{U_{\mathrm{dc}}}{T}_s-\frac{1}{3}{T}_{010}-\frac{2}{3}{T}_{011}$

T ₀₀₀＝T _s-T ₀₁₀-T ₀₁₁-T ₁₁₁

Work as u ₁when being positioned at sector 4, effective vector is 001 and 011; Now, be respectively the action time of Zero voltage vector 000 and 111:

$T_{111}=\frac{u_{z1}}{U_{\mathrm{dc}}}{T}_s-\frac{1}{3}{T}_{001}-\frac{2}{3}{T}_{011}$

T ₀₀₀＝T _s-T ₀₀₁-T ₀₁₁-T ₁₁₁

Work as u ₁when being positioned at sector 5, effective vector is 001 and 101; Now, be respectively the action time of Zero voltage vector 000 and 111:

$T_{111}=\frac{u_{z1}}{U_{\mathrm{dc}}}{T}_s-\frac{1}{3}{T}_{001}-\frac{2}{3}{T}_{101}$

T ₀₀₀＝T _s-T ₀₀₁-T ₁₀₁-T ₁₁₁

Work as u ₁when being positioned at sector 6, effective vector is 100 and 101; Now, be respectively the action time of Zero voltage vector 000 and 111:

$T_{111}=\frac{u_{z1}}{U_{\mathrm{dc}}}{T}_s-\frac{1}{3}{T}_{100}-\frac{2}{3}{T}_{101}$

T ₀₀₀＝T _s-T ₁₀₀-T ₁₀₁-T ₁₁₁

We carry out emulation testing to present embodiment electric system below, and the parameter of motor is as shown in table 1:

Table 1

The parameter of electric machine	Parameter value
		Rated power	5500W
Rated voltage	230V
		Rated current	13.8A
Rated frequency	10.67Hz
		Rated speed	80r/min
Stator phase resistance	1.1Ω
		Stator d axle inductance	77.56mH
Stator q axle inductance	107.4mH
		Zero sequence axle inductance	17.3mH
Number of pole-pairs	8
		VD	200V

Fig. 5 and Fig. 6 is the experimental waveform figure adopting present embodiment common DC bus to be opened to winding permanent magnet motor Systematical control, and system is in steady operational status.Now, aims of systems power is 1000W, and rotating speed is 40 revs/min.Can draw from experimental result, monolateral controlled common DC bus permanent magnet motor system, when not adopting the quick zero passage of electric current, the current zero-crossing point time is long, what now can produce diode rectifier bridge constantly opens shutoff, the spike (see Fig. 5 (b)) causing quantity larger, increases switching loss, strengthens EMI; After adding the quick zero passage method of electric current designed by the present invention, electric current can zero passage rapidly, and reduce the on-off times of diode rectifier bridge, spike quantity significantly reduces (see Fig. 6 (b)), and switching loss reduces, and EMI can be inhibited.Experimental result shows, system proposed by the invention and control method can be good at controlling zero-sequence current, make system high efficiency and stable operation.

Claims (7)

1. suppress the monolateral controlled control method opening the fluctuation of winding permanent magnet motor system power zero crossing of common bus, comprise the steps:

(1) terminal voltage of described permanent magnet motor system, phase current, public DC bus-bar voltage U is gathered _dc, motor speed ω and rotor position angle θ;

(2) the rotor position angle θ described in utilization carries out dq0 Rotating Transition of Coordinate to phase current, obtains the d axle component i of phase current _d, q axle component i _qwith 0 axle component i _z;

(3) according to the d axle component i of described motor speed ω and phase current _d, q axle component i _qwith 0 axle component i _z, calculate the real output P of permanent magnet motor system, meritorious shaft voltage compensation rate Δ u _q, idle shaft voltage compensation rate Δ u _dwith residual voltage compensation rate Δ u _z;

(4) according to described real output P, meritorious shaft voltage compensation rate Δ u _qwith idle shaft voltage compensation rate Δ u _d, by being that the vector control algorithm of zero calculates meritorious shaft voltage instruction u based on idle shaft current _qwith idle shaft voltage instruction u _d;

(5) according to described meritorious shaft voltage instruction u _qwith idle shaft voltage instruction u _dcalculate zero-sequence current reference value I _z; And then according to described zero-sequence current reference value I _zwith 0 axle component i _zpassing ratio resonance controls, and calculates residual voltage instruction u _z;

(6) according to the phase voltage not controlling type AC side of converter in described phase current determination permanent magnet motor system, and dq0 Rotating Transition of Coordinate is carried out to described phase voltage, obtain the d axle component u of phase voltage _d2, q axle component u _q2with 0 axle component u _z2; And then make described d axle component u _d2, q axle component u _q2with 0 axle component u _z2corresponding and idle shaft voltage instruction u _d, meritorious shaft voltage instruction u _qwith residual voltage instruction u _zbe added, obtain the idle shaft voltage instruction u of controllable type current transformer in permanent magnet motor system _d1, meritorious shaft voltage instruction u _q1with residual voltage instruction u _z1;

(7) according to described idle shaft voltage instruction u _d1with meritorious shaft voltage instruction u _q1, utilize SVPWM algorithm to determine the effect duration of corresponding two the effective vectors in sector and this sector at the modulation voltage vector place of described controllable type current transformer; And then according to described residual voltage instruction u _z1with DC bus-bar voltage U _dc, calculate the effect duration of controllable type current transformer two zero vectors;

According to described two effective vectors and the effect duration of correspondence thereof and the effect duration of two zero vectors and correspondence thereof, structure obtains one group of pwm signal to control controllable type current transformer.

2. control method according to claim 1, is characterized in that: calculate the real output P of permanent magnet motor system, meritorious shaft voltage compensation rate Δ u according to following formula in described step (3) _q, idle shaft voltage compensation rate Δ u _dΔ u is compensated with residual voltage _z;

$P=\frac{3}{2}\mathrm{\&omega;}[L_q{i}_q{i}_d+({\mathrm{\&psi;}}_r-L_d{i}_d)i_q-6{\mathrm{\&psi;}}_{3r}\sin \left(3\mathrm{\&theta;}\right)i_0]$

$\left\{\begin{array}{c}\mathrm{\&Delta;}{u}_d=\mathrm{\&omega;}{L}_q{i}_q\\ \mathrm{\&Delta;}{u}_q=\mathrm{\&omega;}{\mathrm{\&Psi;}}_r-\mathrm{\&omega;}{L}_d{i}_d\\ \mathrm{\&Delta;}{u}_z=-3\mathrm{\&omega;}{\mathrm{\&psi;}}_{3r}\sin 3\mathrm{\&theta;}\end{array}\right.$

Wherein: L _dand L _qbe respectively d-axis inductance and the quadrature axis inductance of magneto, Ψ _rand Ψ _3rbe respectively fundametal compoment and the third-harmonic component of permanent magnet machine rotor magnetic linkage.

3. control method according to claim 1, is characterized in that: be the vector control algorithm of zero based on idle shaft current in described step (4), detailed process is as follows:

4.1 make the target output P preset _refdeduct described real output P, obtain power error P _err;

Power error P described in 4.2 couples _errcarry out PI adjustment and obtain meritorious shaft current instruction I _q, with seasonal idle shaft current instruction I _dbe zero;

4.3 make idle shaft current instruction I _dwith meritorious shaft current instruction I _qdeduct the d axle component i of phase current respectively _dwith q axle component i _q, obtain idle shaft current error i _derrwith meritorious shaft current error i _qerr;

4.4 respectively to described meritorious shaft current error i _qerrwith idle shaft current error i _derrcarry out PI adjustment and obtain meritorious shaft voltage error u _qerrwith idle shaft voltage error u _derr; Make described meritorious shaft voltage compensation rate Δ u _qwith idle shaft voltage compensation rate Δ u _ddeduct meritorious shaft voltage error u respectively _qerrwith idle shaft voltage error u _derr, namely obtain meritorious shaft voltage instruction u _qwith idle shaft voltage instruction u _d.

4. control method according to claim 3, is characterized in that: calculate zero-sequence current reference value I by following formula in described step (5) _z:

5. control method according to claim 1, is characterized in that: the concrete computational process that in described step (5), ratio resonance controls is as follows:

First, described zero-sequence current instruction I is made _zdeduct 0 axle component i of phase current _z, obtain zero-sequence current error i _zerr;

Then, to described zero-sequence current error i _zerrcarry out PR adjustment and obtain residual voltage error u _zerr;

Finally, described residual voltage compensation rate Δ u is made _zdeduct residual voltage error u _zerr, namely obtain residual voltage instruction u _z.

6. control method according to claim 1, is characterized in that: by not controlling the phase voltage of type AC side of converter in following relational expression determination permanent magnet motor system in described step (6):

$\left\{\begin{array}{c}{u}_{a2}=\left\{\begin{array}{cc}{U}_{\mathrm{dc}},& \mathrm{if}(i_a<0)\\ 0,& \mathrm{if}(i_a\&GreaterEqual;0)\end{array}\right.\\ u_{b2}=\left\{\begin{array}{cc}{U}_{\mathrm{dc}},& \mathrm{if}(i_b<0)\\ 0,& \mathrm{if}(i_b\&GreaterEqual;0)\end{array}\right.\\ u_{c2}=\left\{\begin{array}{cc}{U}_{\mathrm{dc}},& \mathrm{if}(i_c<0)\\ 0,& \mathrm{if}(i_c\&GreaterEqual;0)\end{array}\right.\end{array}\right.$

Wherein: u _a2~ u _c2be respectively A phase voltage, B phase voltage and the C phase voltage of not controlling type AC side of converter, i _a~ i _cbe respectively the A phase current of permanent magnet motor system, B phase current and C phase current.

7. control method according to claim 1, is characterized in that: according to described residual voltage instruction u in described step (7) _z1with DC bus-bar voltage U _dc, the effect duration of controllable type current transformer two zero vectors is calculated by following rule;

When the modulation voltage vector of controllable type current transformer is positioned at the first sector, two effective vectors corresponding to this sector are respectively 100 and 110; Now, the effect duration of controllable type current transformer two zero vectors is calculated by following formula:

$T_{111}=\frac{u_{z1}}{U_{\mathrm{dc}}}{T}_s-\frac{1}{3}{T}_{100}-\frac{2}{3}{T}_{110}$

T ₀₀₀＝T _s-T ₁₀₀-T ₁₁₀-T ₁₁₁

When the modulation voltage vector of controllable type current transformer is positioned at the second sector, two effective vectors corresponding to this sector are respectively 010 and 110; Now, the effect duration of controllable type current transformer two zero vectors is calculated by following formula:

$T_{111}=\frac{u_{z1}}{U_{\mathrm{dc}}}{T}_s-\frac{1}{3}{T}_{010}-\frac{2}{3}{T}_{110}$

T ₀₀₀＝T _s-T ₀₁₀-T ₁₁₀-T ₁₁₁

When the modulation voltage vector of controllable type current transformer is positioned at the 3rd sector, two effective vectors corresponding to this sector are respectively 010 and 011; Now, the effect duration of controllable type current transformer two zero vectors is calculated by following formula:

$T_{111}=\frac{u_{z1}}{U_{\mathrm{dc}}}{T}_s-\frac{1}{3}{T}_{010}-\frac{2}{3}{T}_{011}$

T ₀₀₀＝T _s-T ₀₁₀-T ₀₁₁-T ₁₁₁

When the modulation voltage vector of controllable type current transformer is positioned at the 4th sector, two effective vectors corresponding to this sector are respectively 001 and 011; Now, the effect duration of controllable type current transformer two zero vectors is calculated by following formula:

$T_{111}=\frac{u_{z1}}{U_{\mathrm{dc}}}{T}_s-\frac{1}{3}{T}_{001}-\frac{2}{3}{T}_{011}$

T ₀₀₀＝T _s-T ₀₀₁-T ₀₁₁-T ₁₁₁

When the modulation voltage vector of controllable type current transformer is positioned at the 5th sector, two effective vectors corresponding to this sector are respectively 001 and 101; Now, the effect duration of controllable type current transformer two zero vectors is calculated by following formula:

$T_{111}=\frac{u_{z1}}{U_{\mathrm{dc}}}{T}_s-\frac{1}{3}{T}_{001}-\frac{2}{3}{T}_{101}$

T ₀₀₀＝T _s-T ₀₀₁-T ₁₀₁-T ₁₁₁

When the modulation voltage vector of controllable type current transformer is positioned at the 6th sector, two effective vectors corresponding to this sector are respectively 100 and 101; Now, the effect duration of controllable type current transformer two zero vectors is calculated by following formula:

$T_{111}=\frac{u_{z1}}{U_{\mathrm{dc}}}{T}_s-\frac{1}{3}{T}_{100}-\frac{2}{3}{T}_{101}$

T ₀₀₀＝T _s-T ₁₀₀-T ₁₀₁-T ₁₁₁

Wherein: T _sfor the switch periods of device for power switching in current transformer, T ₁₁₁and T ₀₀₀be respectively the effect duration of controllable type current transformer two zero vectors 111 and 000 correspondence, T ₁₀₀, T ₀₁₁, T ₁₁₀, T ₀₀₁, T ₁₀₁and T ₀₁₀be respectively the effect duration of six, controllable type current transformer effective vector 100,011,110,001,101 and 010 correspondence.