JPS63223525A - Circuit for digital detection of position and speed by using resolver - Google Patents

Abstract

PURPOSE:To obviate generation of a temp. drift and to obtain sufficient reliability as against a secular change by utilizing the output of a revolver to obtain the information and the position and speed of a rotor in terms of digital values. CONSTITUTION:The clock pulses for formation of a resolver excitation signal generated by a reference signal generating circuit 21 are inputted to a counter 22. The counter 22 outputs an excitation phase thetac of the resolver. A ROM 13, applied with this phase thetac outputs the excitation signal for the resolver 60. The excitation signal is converted 30, 31 to sine wave signals Valpha, Vbeta which excite the resolver 60. A sine wave signal e0 is thereby induced. A zero cross circuit 71, inputted with the signal e0, outputs a zero cross pulse signal. The signal thetac is latched by this signal in a latch 50 and the information on the position of the rotor is outputted at the present point of the time of the resolver 60. A timing circuit 72 outputs a latch pulse signal after the predetermined time. The information on the rotating position of the resolver 60 at the present moment of the time is outputted in a latch 51. The information on the speed of the rotor is obtd. from a ROM 80 via a substractor 40.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a resolver that can detect rotor position and speed information of a motor, etc. in an electric servo device as a digital value based on the output of a resolver. Related to Luper digital position/speed detection circuit.

[Conventional technology]

Generally, in order to control the position and speed of an electric motor, for example, it is necessary to detect the position and speed of the rotor of the electric motor. Conventionally, an optical encoder has been used to detect the position of an electric motor, and a tacho generator, etc. has been used to detect the speed. [Problems to be solved by the invention] However, (1) the above-mentioned optical Since the type encoder uses components that change over time, such as photodiodes, its reliability is not sufficient. Furthermore, since tachogenerators are a type of generator, they are constructed with worn parts such as brushes, and have the disadvantage that they deteriorate over time and generate noise due to sparks and the like. (2
) In terms of position and speed control technology, we have changed from analog control, which caused temperature drift and required offset adjustment.
This is changing to digital control, which does not exist.

For this reason, sufficient reliability is obtained even against changes over time.
A position and speed detection method that allows position and speed information to be obtained in digital values has been desired.

Therefore, the present invention has developed a resolver digital system that can provide sufficient reliability against aging without using conventional optical encoders, tacho generators, etc., does not cause temperature drift, and does not require offset adjustment. The purpose is to provide a position/velocity detection circuit.

[Means for solving problems]

In order to achieve the above object, the present invention is constructed as follows. That is, a reference signal generation circuit 21 that generates a lock pulse for generating a resolver excitation signal, a counter 22 that inputs the excitation signal generation gate and pulse and outputs the resolver excitation phase as a digital value, and a counter 22 that outputs the resolver excitation phase as a digital value. a first memory 23 that receives the excitation phase output as a value and generates a resolver excitation signal as a digital value;
A D-A converter 30.31 receives the resolver excitation signal outputted as a digital value and outputs a first sine wave signal for excitation of the resolver as an analog value, and two of the resolver 60.
A zero cross circuit 71 detects the zero cross point of the rising edge of the second sine wave signal induced on the next side and generates a rising nine zero cross pulse signal, and the digital A latch 50 that latches the excitation phase output as a value and outputs current rotor position information of the resolver 60 as a digital value, and a timing circuit 72 that inputs the rising zero cross pulse signal and outputs a latch pulse signal. and the latch 5 which inputs the pulse signal and outputs the rotor position information at the previous point in time as a digital value.
1, a subtractor 40 which inputs the rotor position information at the current point in time and the rotor position information at the previous point in time, and outputs position difference information; This is a resolper digital position/velocity detection circuit comprising a second memory that outputs velocity information.

[Effect]

As described above, according to the present invention, by using the output of the resolver, sufficient reliability against aging can be obtained without using the optical encoder or tachometer generator that was conventionally required. Furthermore, since position and speed information can be obtained as digital values, there is no temperature drift and no offset adjustment is required.

〔Example〕

The present invention will be described below with reference to embodiments shown in the drawings, but first the theory underlying the present invention will be explained.

The resolver used is one with two-phase excitation and one-phase output as shown in FIG. In FIG. 1, the excitation signal of the resolver is set to a fixed phase θ. = ωct, two-phase sine wave signal τα = Vcsin
ωct, vβ=VccosωCt, the output e6 of the resolver is: ・o=K(ω.-~) sin(ωct-θs, θ,=G
), t・−+11 (K: turns ratio). In formula +11, ωet1−θ. =2tπ (t: integer)...
(2) The fixed phase θ of the resorno 4 at the time tl.

,=ωct1 is determined. From equation (2), 21π0θm
...(3) tl-ω.

θc1-0t1 2tπ+θ□ F&C-ω.

=2tπ+θ.

=θ. ...(4)(
4) θc1 obtained from formula is the resolver rotor position information,
In other words, it is the position information of the electric motor. Next, sample point t
If the rotor position information at =nT is expressed as 0m (nT), the rotor angular velocity information near t=nT, that is, the motor speed information ωm(nT), is expressed as a digital value as (Δ
θtn(nT)=ΔθmcnT)-0m(n-1-T)
0m(n'r) is obtained from equation (5). If equation (6) is linearly approximated, ω. 40m(nT) %(nT angle-7-(1-Δ”m(nT)/2') +
++ (7). That is, the speed information of the electric motor can be obtained from equation (7).

Next, an embodiment of the present invention shown in the block diagram of FIG. 2 will be described. The reference signal generation circuit 21 generates a resolver excitation signal, lock, and pulse.

This resolver excitation signal generation pulse is input to a counter 22, and this counter 22 calculates the excitation phase θ of the resolver by counting the resolver excitation signal generation pulse i4. Outputs as a dizotal value.

This di? ) Resolver excitation phase θ output in total value
C is read-only memory (hereinafter referred to as ROM 23)
This ROM 2J outputs a resolver excitation signal stored in advance as a digital value. The resolver excitation signal output as this digital value is input to the D-A converter 30.31, and this D-A
The converter 30, 31' converts the excitation signal outputted as a digital value into an analog signal, and converts the excitation signal outputted with the digital value into an analog signal,
The two-phase sine wave signal yaα+vca t nωeLsτβ=
Vccooωct is generated and the resolver 60 is excited.

The rotor winding of the resolver 60 receives a second sine wave signal e6.
=K(ωe−咄)sin(ω.t−θ is induced.

The zero/loss circuit 71 receives the second sine wave signal and outputs a rising/zero cross pulse signal at the time t1. This rising 9 zero cross/gurus signal is latch 50
The latch 50 inputs the excitation phase θ of the resolver as a digital value. is latched by the rising/zero Ross Noculus signal, and the resolver rotor position information θ at the current time t=nT of the resolver is obtained.
Output m(nT) as a digital value. The timing circuit 72 inputs the rising zero cross pulse signal and outputs the third
As shown in the figure, after the specified time 1x, this signal is
A latch/4 pulse signal is generated at tx<'rs (for example, at the falling zero cross point of the second sine wave signal).

This latch signal is input as a latch signal to the latch 51, and the latch 5 inputs the signal at the previous time point t=n-1.
The rotor position information of each resolver (=T) is also output as a digital value. The subtracter 40 calculates the current time t==nT
Resol 2600 rotor position information θm(n'r) at
Inputting the resolver rotor position information θm (nt-'r) at the previous time point t=n-1·T and performing subtraction,
Therefore, the rotor position difference information Δθm(nT)=θm(n'
r)-0m (n'seal-・T) is output. The read-only memory (hereinafter referred to as ROM JO) stores in advance the calculation result of equation (7) for the rotor position difference information Δθm(n'r) as data,
The rotor position difference information Δθm(n'r) is input as an address. Then, by reading the data in the ROM 80 between the falling Rossnoculus signal of the second sine wave signal and the Chi-Grus signal, rotor speed information ~(nT) can be obtained. The state of each signal mentioned above is summarized in FIG.

According to the embodiment of the present invention described above, the rotor position and speed information of an electric motor etc. can be obtained in digital values using the resolver 60 and a simple circuit configuration. Therefore, no temperature drift occurs and no offset adjustment is required.

〔Effect of the invention〕

According to the present invention described above, the conventional optical encoder,
It is possible to provide a low-cost resolper di-notal position/speed detection circuit that has sufficient reliability against aging without using a tachometer generator, does not cause temperature drift, and does not require offset adjustment. .

[Brief explanation of the drawing]

Figure 1 is a principle diagram of the resolver used in the present invention, Figure 2
FIG. 3 is a diagram showing the configuration of an embodiment of the present invention, and FIG. 3 is a timing diagram showing signals of various parts in the embodiment of FIG. 21... Reference signal generation circuit, 22... Counter;
13.80...-ROM130.31...D-A converter, 60...Resolver, 71...Zero cross circuit, 7
2...Timing circuit, 50.51...U, C, 4
0...Subtractor.

Claims (1)

[Claims] a reference signal generation circuit (21) that generates a resolver excitation signal generation clock pulse; a counter (22) that receives the excitation signal generation clock pulse and outputs the resolver excitation phase as a digital value; a first memory (23) which inputs the excitation phase outputted from the digital value and generates a resolver excitation signal with a digital value; The D-A converters (30) and (31) that output wave signals and the zero cross point of the rising edge of the second sine wave signal induced on the secondary side of the resolver (60) are detected, and the zero crossing point of the rising edge is detected. a zero cross circuit (71) that generates a pulse signal, and latches the excitation phase output as the digital value by the rising zero cross pulse signal;
A latch (50) that outputs current rotor position information of the resolver (60) as a digital value, a timing circuit (72) that inputs the rising zero cross pulse signal and outputs a latch pulse signal, and the latch pulse A latch (51) inputs a signal and outputs the rotor position information at the previous point in time as a digital value, inputs the rotor position information at the current point in time, and the rotor position information at the previous point in time, and outputs the rotor position information at the previous point in time. A resolver digital position/speed detection circuit comprising a subtracter (40) that outputs difference information, and a second memory (80) that inputs the position difference information and outputs speed information as a digital value. .