CN104917427A - Electric current optimization method for low-velocity zone of hybrid excitation synchronous machine - Google Patents

Abstract

The invention discloses an electric current optimization method for a low-velocity zone of a hybrid excitation synchronous machine. The electric current optimization method comprises steps of: controlling a given current to be a maximum value during starting and accelerating, controlling output torque to be maximum, and obtaining minimum copper loss current when gradually entering a stable state. According to the electric current optimization method for the low-velocity zone of the hybrid excitation synchronous machine, designed by the invention, the problem of numerous equation solving calculations existing in the traditional low-velocity zone control strategy when minimum copper loss of an electric motor is realized is substantially solved, the given electric current algorithm is optimized, and the electric current optimization method is simple and reliable.

Description

A kind of electric current optimization method for hybrid exciting synchronous motor low regime

Technical field:

The present invention relates to a kind of electric current optimal control method realizing copper loss-minimization while dynamic property promotes for hybrid exciting synchronous motor low regime, belong to hybrid exciting synchronous motor control technology.

Background technology:

Permagnetic synchronous motor (PMSM) adopts permanent magnet as single magnetic potential source, air-gap field in motor is caused to regulate difficulty, hybrid exciting synchronous motor (HESM) introduces set of excitation winding on PMSM basis, makes it have the high and electro-magnetic motor flux control of permagnetic synchronous motor power density and is easy to advantage.Coordinate the control of armature supply and exciting current, the target of low speed high torque output and high speed wide speed regulating range can be realized, have broad application prospects in electric automobile field.Therefore, HESM electric current coordination optimization is controlled to carry out research and can improve motor runnability.

In HESM control method, mostly adopt zone control tactics, low regime main flow control objectives reduces the efficiency that copper loss improves motor, and high velocity adopts field weakening control method, to improve rotating speed.At present, the optimization given value of current of low regime copper loss-minimization calculates mainly through solving an equation, and this method exists the large shortcoming of amount of calculation, and can not realize torque output maximization in the dynamic processes such as acceleration, braking; And i when obtaining copper loss-minimization by Lagrangian Arithmetic _qwith i _frelation, and use recursive algorithm to obtain final given value of current, eliminating solves an equation calculates but adds algorithm complexity.

Therefore, in existing control strategy, the research of low regime copper loss-minimization, ignores the optimization of algorithm, and in the transient process of motor, fail to consider the raising of motor dynamics performance, the maximizing performance of motor is not brought into play.

Summary of the invention

In order to simplify the given algorithm of HESM low regime optimal current, the invention provides a kind of low regime electric current optimization method based on HESM newly, motor is maximized at unstable state stage Driving Torque, promote dynamic property, when progressing into stable state, take new optimized algorithm, reduce copper wastage, improve operational efficiency.

For achieving the above object, the technical solution used in the present invention is

For a low regime electric current optimization method of HESM, the whole service interval of motor is divided into low regime and high speed weak magnetic area.Consider between low regime, in starting, acceleration, braking procedure, control maximum within the scope of given reference current, make Driving Torque maximum, improve dynamic property; After progressing into stable state, to raise the efficiency as target, by constantly comparing the change changing a certain given value of current rear motor copper loss, determine the size of the given value of current that actual needs changes and knots modification thereof, to realize the minimized target of copper wastage.

Beneficial effect: the low regime electric current optimization method for HESM that the present invention proposes, has following advantage relative to existing control method:

1, consider separately the non-steady states such as starting, acceleration and braking, export breakdown torque and improve dynamic property.

2, in stable operation stage, can realize copper wastage without the need to the complex calculations such as to solve an equation and minimize, algorithm is simple.

Accompanying drawing explanation

Fig. 1 is the low regime electric current Optimizing Flow figure for HESM.

Fig. 2 is mixed excitation electric machine control-driven system structure chart;

Embodiment:

Below in conjunction with accompanying drawing, the present invention is further illustrated.

For an electric current optimization method for HESM low regime, the whole service interval of motor is divided into low regime and high speed weak magnetic area.In the given controller of the reference current of Fig. 2, consider that low cruise is interval, in starting, acceleration, braking procedure, control maximum within the scope of given reference current, make Driving Torque maximum, improve dynamic property; After progressing into stable state, to raise the efficiency as target, take proposed copper loss-minimization electric current optimized algorithm, realize the target that copper loss is minimum, excavate out the performance of motor fully.Illustrated with regard to low regime electric current optimization method various piece below.

Low regime: as shown in Figure 1, detects PI speed regulator output signal in Fig. 2, judges that whether it is saturated.Before entering stable state, speed regulator is saturated, loses regulating action, now keeps i _q, i _ffor maximum, i.e. i _qmaxand i _fmax, i simultaneously _d=0, Driving Torque is maximum; After progressing into stable state, speed regulator exits saturated, i _qset-point reduces, thus in motor, electromagnetic torque reduces, until balance each other with load torque.From torque formula (1), same torque can by different i _q, i _fbe combined to form, then there is one group of electric current and make copper wastage minimum, given therefore at speed regulator in the process reduced, coordinate exciting current given, thus make the copper loss of motor minimum.

$T_e=\frac{3}{2}{\mathrm{pi}}_q({\mathrm{\Ψ}}_{pm}+M_{sf}{i}_f)---\left(1\right)$

When speed regulator starts to exit saturated, when there is Δ i _qduring the minimizing of (known), can obtain new torque given, now exciting current is given constant, copper wastage P now can be calculated by copper loss formula (2) _cu1; From analysis, new torque is given also can be given by reducing exciting current realize, its amount reduced is calculated by formula (3), thus can calculate copper wastage P now _cu2.As shown in Figure 1, two copper loss P are compared _cu1and P _cu2size, select copper loss little finally determine need regulate given value of current and need regulate size.

$P_{cu}=\frac{3}{2}{R}_s\·i_q^2+R_f\·i_f^2---\left(2\right)$

$\frac{3}{2}p(i_q^{*}-{\mathrm{\Δi}}_q)({\mathrm{\ψ}}_{PM}+M_{sf}{i}_f^{*})=\frac{3}{2}{\mathrm{pi}}_q^{*}({\mathrm{\ψ}}_{PM}+M_{sf}(i_f^{*}-{\mathrm{\Δi}}_f))---\left(3\right)$ 。

Claims (2)

1. for an electric current optimization method for hybrid exciting synchronous motor low regime, it is characterized in that, comprising: given electric current is maximum in starting, accelerator, controlling Driving Torque maximum, when progressing into stable state, obtaining copper loss-minimization electric current.

2. a kind of electric current optimization method for hybrid exciting synchronous motor low regime according to claim 1, is characterized in that: coordinate current i _q, i _fgiven, in control procedure, reduce i by constantly to compare _qor i _fthe change of rear motor copper loss, determines the given value of current that actual needs changes and knots modification size thereof.Namely when speed regulator exits saturated, according to knots modification Δ i _q, other given value of currents are constant, calculate now copper loss; Only reduced according to given electromagnetic torque principle of invariance again knots modification Δ i _f, other given value of currents are constant, calculate now copper loss, are condition with copper loss-minimization, determine the final current component and the knots modification size thereof that need reduction.