SU392327A1 - METHOD OF MEASURING ANGULAR POSITION OF A ROTOR OF A PROMOTIONAL ELECTRIC MACHINE - Google Patents

Description

one

The known methods for measuring the angular position of the rotor of an AFMIC electric machine by obtaining a signal proportional to the angle of rotation of the rotor are complex, since they require the installation of special sensors on the rotor.

To simplify these methods in the present invention, a high frequency voltage is applied to the stator windings of the machine and the high frequency current envelope of the stator winding is measured, which is used to judge the angular position of the rotor.

To obtain signals characterizing the moments of rotor passage through predetermined angular positions, the specified high frequency signal is alternately applied to each of the phases of the stator, and the envelope value of the received high frequency current is compared with the same current value. In order to make it possible to measure at a specified electric facility in the mode of a brushless DC motor with power commutation of the phases, the specified alternation of applying a high frequency voltage to the motor phases is carried out synchronously with power commutation.

FIG. 1 Nokasapy curves of changes in the envelope of the high-frequency current for different phases as a function of the angle of rotation of the rotor; on

FIG. 2 — Principle electrical circuit for supplying high-frequency voltage to the phases of an electric machine.

The proposed method for measuring the angular position of the rotor is based on a change in the inductive resistance (Xd, Xq) of the winding of the phase of the uni-polar electric machine.

for high frequency currents as a function of the angle of rotation of the rotor. When applied to the phase winding (I, II, III) are supplied from the source Gy through an opening LC filter. A high-frequency voltage, a high-frequency current (fi) at

changing the position of the rotor will change. The larger Xd and Xq maschiny, the greater the ratio of the maximum current to the minimum. A change in high frequency current can be used to measure

rotor position. Rotation of the rotor on the pole division corresponds to one period of change of the high-frequency current. To obtain a signal characterizing the moment of rotor passing through a given angular position, the high-frequency current is compared with the specified current value and the moments of equality are fixed using a zero-body (Fig. 2; in Fig. 1 the moments of equality of a given current / oi and high-frequency phase , for example, / j).

When high frequency voltage is applied to one phase of the engine, we can fix the passage of the rotor of only one point in the pole division of the machine.

When using this method of measuring the angular position of the rotor to control the power switch of a brushless motor, it is necessary to obtain intermediate points on the pole division, shifted by 60 °. For this purpose, you can use the windings of other phases of the machine. However, simultaneously applying voltage to all three phases of the machine, with the opposite direction of the magnetizing forces of the three phases, leads to the loss of modulation of the current of the phases in the angle of rotation.

If the direction of the magnetizing forces of the three phases is consistent, (keys Ki, JKz, Kz are simultaneously closed, Fig. 2). the high-frequency current envelope is shifted in two phases of the maschine by 60 ° (current curve / l and / u, Fig. 1). This is because the axis of the measured phases (II and / III), in the latter case, is located at an angle of 60 ° to the axis of the resulting magnetizing force of the machine.

To avoid this, it is proposed to apply high-frequency voltage alternately to the phases of the engine (keys Ki, Kz, Kz close alternately, Fig. 2). In this case, at a given current, the moments of equality of its high-frequency current of the three phases / b / p, / u (Fig. 1) will be distributed by the angle of rotation through 60 °.

When using this method of measuring the angular position of the rotor in a brushless DC motor, it is necessary to synchronize the switching of keys Ki, Kz, Kz (Fig. 2) with the switching of keys of the power switch of the engine, since in this case the condition for creating the maximum torque of the engine will be ensured. The movement of the rotor is accompanied in this case by moving the measuring high-frequency floor in the machine and

moving the power floor with a low frequency.

When using this method of measuring the angular position of the rotor to the mask

no additional wires are required, only three or four wires are suitable. The magnitude of the useful signal depends on the difference Xd and Xq of the machine. The biggest difference between Xd and Xq happens in synchronous machines.

with electromagnetic excitation without a damper cell, as well as in magnetoelectric machines with pole tips. These machines are widely distributed, so this method can be widely used.

Subject invention

Claims (3)

1. A method of measuring the rotor angular position of a pole-mounted electric machine by obtaining a signal proportional to the angle of rotation of the rotor, characterized in that, in order to simplify the measurement, a high-frequency voltage is applied to the stator windings of the machine and the high-frequency envelope current of the stator winding is measured, by which judge the angular position of the rotor. 2. The method according to claim 1, characterized in that, in order to obtain signals characterizing the moments of rotor passage through predetermined angular positions, high-frequency voltage is applied to each of the stator phases alternately, and the envelope value of the obtained high-frequency current is compared with the same set current value. 3. The method according to paragraphs. 1 and 2, characterized in that, in order to make it possible to measure at a specified electrical location in the mode of a brushless DC motor with power commutation of the phases, the alternation of applying a high frequency voltage to the motor phases is performed synchronously with the power commutation. J 01 t 02