CN104283469A - Rotor position detection method of synchronous motor speed control system using photoelectric pair tube - Google Patents

Abstract

The invention discloses a synchronous motor speed regulating system rotor position detection method with the adoption of photoelectric pair transistors, and relates to the technical field of rotor position detection on synchronous motor speed regulating systems driven by sine wave current. According to the rotor position detection method disclosed by the invention, at least two photoelectric pair transistors are sequentially arranged on the circumference, which is concentric with a rotor, at an equal interval, a speed measuring disc with tooth grooves having the same widths is fixed on a rotary shaft which is concentric with the rotor, and the tooth grooves of the speed measuring disc sequentially shelter the photoelectric pair transistors when the rotor rotates to enable the photoelectric pair transistors to output high electric level; with six positions in which an output signal of arbitrary one photoelectric pair transistor jumps in an electricity period as standard positions, the current position of the rotor theta is as follows: theta=theta<last>+omega t<step>+theta<cf>. Compared with a position detection method with the adoption of a photoelectric encoder or a rotary transformer, the rotor position detection method has the advantage of low cost. Compared with a hardware phase-locked loop (PLL) circuit-based rotor position detection method with the adoption of the photoelectric pair transistors, the rotor position detection method has the advantage of high interference resistance, high reliability, capability of accurately detecting a high-frequency input signal, high accuracy in rotor angular fine division and easiness in driving and controlling a circuit, and low cost.

Description

Rotor position detection method of synchronous motor speed control system using photoelectric pair tube

technical field

The invention relates to the technical field of detecting the rotor position of a synchronous motor speed regulating system driven by a sine wave current.

Background technique

Synchronous motors are divided into electric excitation synchronous motors, permanent magnet synchronous motors and hybrid excitation synchronous motors. In particular, rare earth permanent magnet synchronous motors have the advantages of less loss, high efficiency, and obvious power-saving effects, and are widely used. With the rapid development of electronic technology, control theory and rare earth permanent magnet materials, synchronous motors driven by sine wave currents have been widely used in servo, drive and other fields due to their unique precision drive characteristics. The cost of motor drive systems It has also attracted the attention of scholars in related fields, especially in industrial and civil applications, where low cost is particularly important.

In the existing sine wave synchronous motor drive system, the rotor position detection usually uses a photoelectric encoder or a resolver, which has a high cost, which limits the further popularization and application of this type of motor in some price-sensitive occasions.

Contents of the invention

In order to reduce the cost of the sine wave synchronous motor speed control system, the invention proposes a rotor position detection method of the synchronous motor speed control system using a photoelectric pair tube.

In the present invention, at least two photoelectric pair tubes are arranged at equal intervals in turn on the circumference concentric with the rotor, and a tachometer disk with the same width as the tooth groove is fixed on the rotating shaft concentric with the rotor. Make the photoelectric pair tube output high level; take the 6 positions where the output signal of any photoelectric pair tube jumps in one electrical cycle as the standard position;

Then the current position θ of the rotor is: θ=θ _last + ω t _step +θ _cf

Among them, θ _last is the rotor position at the last moment;

ω is the current rotor speed;

t _step is the time interval;

θ _cf is the correction angle.

Compared with the position detection method using photoelectric encoder or rotary transformer, the present invention has the advantage of low cost. Compared with the rotor position detection method based on the hardware phase-locked loop (PLL) circuit using photoelectric tubes, it has the following advantages: 1. Strong anti-interference ability, high reliability, and can accurately detect high-frequency input signals; 2. Rotor angle The subdivision precision is very high; 3. The driving control circuit is simple and the cost is low.

Description of drawings

Figure 1 is a flow chart of the rotor position detection subroutine.

Fig. 2 is a schematic structural diagram of a rotor position detection device.

Detailed ways

Take the rotor pole-to-pole sine wave synchronous motor speed control system using the current hysteresis control strategy as an example. The system uses TI's TMS320F2812 as the control chip. The general structure of its position detection part is:

As shown in Figure 2, three photoelectric pair tubes 1 are arranged at a distance of 15° from each other on the circumference concentric with the rotor 4, and a speed measuring disk 2 with the same width of the tooth slots and 8 teeth is fixed on the rotating shaft 3 concentric with the rotor 4 . When the rotor rotates, the tooth slots on the speed measuring disc 2 block the photoelectric pair tube 1 in sequence.

When the teeth of the tachometer disc 2 block the optical path of a certain photoelectric pair tube, the photoelectric pair tube outputs a high level, otherwise it outputs a low level. Because the rotor position is uniquely determined when the output signal of the photoelectric pair tube jumps, so define 6 positions where the output signal of any photoelectric pair tube jumps within one electrical cycle (360°/8=45°) for the standard position.

The controller first calculates the rotor position θ according to the position signal output by the radio and television tube at the standard position, so as to realize the precise positioning of the rotor position.

The current position θ of the rotor is: θ=θ _last + ω t _step + θ _cf

Among them, θ _last is the rotor position at the last moment;

ω is the current rotor speed;

t _step is the control time interval;

θ _cf is the correction angle.

During detection, first calculate the current rotor speed based on the position signal captured at the standard position, and assign it to the current rotor speed ω, then according to the rotor position θ _{last at the previous moment,} the current rotor speed ω, the control time interval t _step and The correction angle θ _cf is calculated for the current rotor position θ .

Its workflow is shown in Figure 1.

Claims (1)

1. The rotor position detection method of the synchronous motor speed control system using photoelectric pair tubes, arrange at least two photoelectric pair tubes at equal intervals on the circumference concentric with the rotor, and fix a speed measuring disc with the same width as the tooth groove on the rotating shaft concentric with the rotor , when the rotor rotates, the cogs of the tachometer disc cover the photoelectric pair tube in turn, so that the photoelectric pair tube outputs a high level; the 6 positions where the output signal of any photoelectric pair tube jumps in one electrical cycle are taken as the standard positions; Then the current position θ of the rotor is: θ=θ _last + ω t _step +θ _cf Among them, θ _last is the rotor position at the last moment; ω is the current rotor speed; t _step is the time interval; θ _cf is the correction angle.