JPH0311987A - Detection method of rotating position of motor - Google Patents

Abstract

PURPOSE:To share a system by detecting a mechanical angle rotating position of a motor from a secondary winding of a resolver. CONSTITUTION:A rotating position detection system of an AC motor 10 is constituted of a bipolar resolver 1 connected to the rotary shaft thereof and a function generator 101 consisting of memories of R/D converter 100, ROM, etc. An output-signal phim of the R/D converter 100 is a digital signal indicating a mechanical angle rotating position of the motor 10. The rotating position phim is induced by the function generator 101 to output a specific electrical angle phie corresponding to the number of poles of the motor 10.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a method for detecting the rotational position of an electric motor.
The present invention relates to a rotational position detection method for detecting the rotational position of a motor as an electrical angle using a resolver.

(Prior Art) Conventionally, resolvers have been used to detect the speed of an electric motor and the rotational position of a shaft. Figure 3 shows how this resolver is used to control the speed of an AC motor.

Here, the resolver is a type of rotating transformer with a structure similar to a wound induction machine. - The stator side of the resolver 1 with phase excitation/two-phase output - When the excitation signal (sinωt) is applied from the oscillator 2 to the next winding 1a, 1. Orthogonal winding 1
From b and lc, a sin and cos two-phase amplitude modulation signal (cos θ・si
nωt, 5inO·sinωt) is obtained.

These two-phase signals are sent to the converter 3, which compares the digital position signal φ, which is the output of the counter 8, with the rotational position 0 of the resolver 1, and calculates the difference between θ and φ by 5.
It is output as a signal in(O-φ)·sinωt. This output signal is synchronously rectified in the synchronous rectifier circuit 4 using the excitation signal sinωt from the oscillator 2. The output signal of the synchronous rectifier circuit 4 is then smoothed through a low-pass filter 5.

After being input to an integrator 6 and integrated, it is output as a speed signal N of the motor.

This speed signal N is also sent to a voltage controlled oscillator (VCO) 7, and the voltage controlled oscillator 7 outputs a pulse corresponding to the speed signal N. At the same time, this output pulse is sent to a counter 8, and the output position of the counter 8 is The signal φ is controlled.

Here, the integrator 6 operates so that its human input signal is zero, that is, the rotational position 0 of the resolver 1 and the output position (R number φ) of the counter 8 match, so the output position signal φ matches the rotational position θ. I will do it.

In addition, the part surrounded by the dashed line in Fig. 3 is.

This is commercially available as an R/D (resolver/digital) converter 100.

(Problems to be Solved by the Invention) As described above, the resolver and the R/D converter 100
In combination with this, the speed and rotational position of the motor can be determined. On the other hand, in recent years, advances in vector control technology have made it possible to perform high-performance control of AC motors, and such high-performance control requires information on the electrical angle position of the motor.

Here, in order to detect the electrical angle rotational position of the electric motor using the resolver 1 and the R/D converter 100, the number of poles Pm of the electric motor 10 and the number of poles Pr of the resolver 1 are determined as shown in FIG. It is necessary to make them match, and when Pm=Pr, the output position signal φ of the R/D converter 100 becomes the electrical angle rotational position of the electric motor 10.

Therefore, in order to control the speed of the electric motor with high performance, it is necessary to use a resolver whose number of poles is the same as that of the electric motor. For this reason, in the past, it was necessary to have resolvers with various types of pole numbers depending on the number of poles of the motor, but this meant that the cost of the system was low in view of the need to standardize the motor drive system. This was a major factor in increasing the

The present invention was proposed to solve the above-mentioned problems, and its purpose is *! A motor rotational position that makes it possible to detect the electrical angle rotational position and speed using a common circuit configuration, regardless of the number of poles of the PIJ machine and resolver, which makes it possible to reduce the cost of the motor drive system. The object of the present invention is to provide a detection method.

(Means for Solving the Problems) In order to achieve the above object, the present invention makes it possible to detect mechanical angle rotational positions by, for example, combining a two-pole resolver and an R/D converter, regardless of the number of poles of the electric motor. The mechanical angle position is detected and the digital signal output thereof is converted into an electrical angle rotational position by a function generator such as a ROM (read only memory).

That is, the present invention detects the mechanical angle rotational position of the electric motor from the output signal of the secondary winding of the resolver coupled to the rotating shaft of the electric motor, and calculates the mechanical angle rotational position according to the human output characteristics according to the number of poles of the electric motor. This is converted into the electrical angle rotational position of the motor using a variable function generator.

(Function) According to the present invention, a two-pole resolver can be used regardless of the number of poles of the motor, and when the number of poles of the motor changes, the corresponding electrical angle rotation can be achieved by changing the contents of the function generator. The location can be detected.

Therefore, in terms of hardware, it is possible to detect the rotational positions and speeds of a plurality of electric motors having different numbers of poles using a motor drive system having the same configuration.

(Example) An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 shows a schematic configuration of a rotational position detection system for an electric motor to which this embodiment is applied. A two-pole resolver, 100 is an R/D converter having the same configuration as in FIG. 3, and 101 is a function generator consisting of a memory such as a ROM.

Here, since the resolver 1 has two poles, the R/D converter 1
The output signal φm of 00 is a digital signal indicating the mechanical angle rotational position of the electric motor 10.

Next, Figure 2 (,) shows the rotational positions O and I/D of the motor shaft.
An example of the relationship with φm outputted from the converter 100 is shown, and in the range from OD to 360°, a mechanical angle rotational position φm matching the rotational position 1ξ0 is outputted from the R/D converter lOO. This mechanical angle rotational position φm is determined by the function generator 101
The function generator 101 outputs a predetermined electrical angle φe corresponding to the number of poles PII of the motor 10.

Note that FIG. 2(b) shows the function generator 10 when the number of poles of the motor 10 is Pm=4, and FIG. 2(c) shows the function generator 10 when the number of poles of the motor 10 is <Pm=6.
1, and the value of φe relative to φm can be easily changed by changing the contents of the ROM. Also, as can be seen from this example, the function generator 101
The function within may be configured such that its input/output relationship outputs data equivalent to (Pm/Pr) times the electrical angle rotational position for one rotation of the input rotational angle (360° in mechanical angle).

According to this embodiment, the electrical angle rotational position of the motor can be determined from the mechanical angle rotational position by simply changing the content representing the input/output relationship of the function generator 101 according to the number of poles of the motor. , J, % can be used to detect the speed of the motor and the position of the rotating shaft.

Note that the present invention can be applied to detecting the rotational position of not only AC motors but also DC motors.

(Effects of the Invention) As described above, according to the present invention, the electric current fljJ with any number of poles
The rotational position of the electric motor can be determined by combining a motor with, for example, a two-pole resolver, and converting the mechanical angle rotational position, which is the output of the resolver, into an electrical angle rotational position using a function generator that is much cheaper than a resolver. Therefore, by changing the input/output characteristics of the function generator according to the number of motor poles, the rotational position can be detected for motors with various numbers of poles.

Therefore, motors with various numbers of poles can be driven by a single drive system, and costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a motor rotational position detection system to which an embodiment of the present invention is applied, and FIG. 2(a) is a diagram showing the relationship between the motor shaft rotational position and the output of the R/D converter. , Figures (b) and (C) are input/output characteristic diagrams of the function generator, Figure 3 is a principle diagram of motor rotational position detection, and Figure 4 is a combination of the electric motor, resolver, and R/D converter. FIG. 1... Resolver 10... AC motor 100
...Resolver/digital converter (R/D converter) 1
01...Function generator patent applicant Fuji Electric Co., Ltd. \← G, ←

Claims (1)

[Claims] A mechanical angle rotational position of the motor is detected from an output signal of a secondary winding of a resolver coupled to a rotating shaft of the motor, and input/output characteristics of the mechanical angle rotational position are varied according to the number of poles of the motor. A method for detecting a rotational position of an electric motor, comprising converting the rotational position into an electrical angle rotational position of the electric motor using a function generator.