JPS5917781B2 - Rotation speed detection method using multipolar resolver - Google Patents

Description

[Detailed description of the invention] The present invention relates to a novel means of rotational speed detection.

Generally, when configuring a position servo system, it is necessary to add a speed loop to stabilize the system and improve responsiveness, and in this case, a DC tachogenerator, etc. must be separately installed as a speed detector. .

In other words, position servo systems are used to control machine tool positioning, etc., but in the conventional technology, two systems are used for position and speed detection.
Two detectors were required.

Furthermore, there is another recent trend in servo systems.
There is an active movement toward C (interchange). As a position and velocity detector in this AC servo system, a frequency-voltage (f/V) converter is used to convert the generated signal from a pulse generator (PG) or an optical tachogenerator (off-tacho) into a brushless one. There is a method to use. However, in this case, there is a limit to the number of pulses of the generation signal, so there is a limit to control during low-speed operation.

On the other hand, resolvers are brushless electromagnetic detectors that match well with motors, but commonly used resolvers have a small number of poles (for example, 2 poles), so the problem is that the modulation frequency is small and difficult to detect. Ta.

Therefore, in the present invention, since the resolver output signal can be phase-modulated or frequency-modulated with respect to its excitation frequency, by extracting the frequency difference between the excitation frequency and the modulation wave, a signal proportional to the speed can be obtained. , and in this case, the purpose is to derive the principle that the detection sensitivity can be increased as the number of poles increases, and to provide a means for detecting rotational speed using a multi-pole resolver.

FIG. 1 is an electrical route diagram of the first embodiment (two-phase excitation) of the present invention.

1 is a resolver that has two-phase stator windings (excitation windings) Wα, Wβ and a winding WD that detects the rotor position; however, the rotor winding WD is placed on the stator side, and it is also possible to make it brushless. However, in principle, the same applies to the following embodiments, which are placed on the rotor side for ease of understanding.

Further, θe represents an electrical angle. 2 is the winding Wα
・Two-phase sine wave oscillator (excitation power supply) for flowing two-phase excitation current to Wβ; 3 and 4 are waveform shaping circuits for shaping the output signals of the excitation power supply 2 and resolver 1 into square waves; 5;
6 is a frequency-to-voltage (f/V) converter for converting the square wave pulse train into voltage, 7 is a differential amplifier for extracting the deviation voltage of the f/V converters 5 and 6, and 8 is a detection speed output terminal. It is.

FIG. 2 is an electrical block diagram of a second embodiment (three-phase excitation) of the present invention.

20 is a three-phase sine wave generator, 10 is 12 in electrical angle spatially
Three-phase excitation windings WR arranged at different positions of the zero phase,
This resolver has WS and WT stator windings and a WD rotor winding that detects the rotor position.

FIG. 3 is a block diagram of a third embodiment (multi-four-phase excitation) of the present invention.

200 is a multi-(j1) phase sine wave generator, 100 is an electrical angle, and n-phase excitation windings Wl, W2, W3 arranged at different positions with 2π/n phases, where n is a positive integer.・・・
It is a resolver that has a Wn stator winding and a WD rotor winding for detecting the rotational position of the rotor.

Therefore, even in three-phase and multi-phase excitation, the output stage from the waveform shaping circuits 3 and 4 to the f/V converters 5 and 6 to the differential amplifier remains the same in all embodiments.

Now, the detection winding WD of the resolver 1 generally has the following (
Voltage E shown by equation 1).

is induced. Here, E is the output voltage (constant amplitude) θe
is the electrical angle of the resolver rotor, and θe=f(N), that is, the function of the motor rotational speed N (formula l), obtains a phase-modulated or frequency-modulated signal depending on the rotational speed and direction of the resolver rotor. This indicates that the

That is, the output voltage frequency F of the detection winding.

However, when f=ω/2π, the excitation frequency ±Δf changes by the frequency change according to the rotation speed.

Therefore, by extracting the difference between the excitation frequency f of the excitation winding and the voltage obtained by f/V conversion of the output voltage frequency FO of the detection winding, a frequency change component Δf corresponding to the speed can be obtained.

In this case, the filter time constant of the f/V converter is equal to the output pulse of a conventional pulse generator (PG) or optaco.
・Compared to the system in which the speed signal is obtained by converting /V), it is possible to select a sufficiently small value, resulting in excellent responsiveness.

Further, there is no problem of pulsation occurring during low speed rotation.

Then, the resolvers 10, 10 during three-phase and multi-phase excitation
In the case of two-phase excitation, the induced voltage of 0 is Sin(ωt+θe
), in three-phase excitation, Ksin(ωt+θEX), and in n-phase excitation, Ksin(ωt+θe), and only the coefficient k or k′ is different.

In addition, a three-phase sine wave generator 20 and a polyphase sine wave generator 200
, the output of the 2-phase sine wave generator 2 changes from 2-phase to 3-phase or 2-phase
It can be easily constructed by using a phase->n-phase converter. Although an analog system is used in this embodiment, it is also possible to obtain the speed signal digitally.

However, since the digital system has an error of 1 digit, a pulse generator (PG) with a large number of pulses is appropriate.

Furthermore, the relationship between the excitation windings Wα, Wβ and the detection winding WD of the resolver 1 can be changed by changing the positions of the two and exciting the detection winding side. A two-phase signal is obtained.

(The carrier in this case is the excitation frequency). If a phase modulation signal is output from this two-phase signal, speed detection similar to this embodiment can be performed. Actual value in this example →
Let me introduce 1. Number of resolver poles: 100P (poles), rotation speed: 1800 rpm (rotations per minute), △f=1500H
2 (-. rutz), excitation frequency = 5 to 15 kHz, (kilo Hertz).

Thus, according to the present invention, when adding a velocity rube to a position servo system, it is possible to control both with a resolver.
The ripple effect is huge.

Moreover, if the number of poles and the number of phases of the resolver are the same as those of the controlled motor (synchronous machine), the current distribution signal of the motor can be directly used.

[Brief explanation of the drawing]

1 through 3 are process diagrams of an embodiment of the present invention. 1.10,100...Resolver, 2,20,2
00... 2-phase, 3-phase, n-phase sine wave generator (excitation power supply), 3.4... Waveform shaping circuit, 5, 6...
...Frequency-to-voltage (f/V) converter, 7...
・Differential amplifier, 8...Detection speed output terminal, Wα,
Wβ, WR, WS, WT, Wl~W ``...excitation winding, WD...detection winding its induced voltage EO its frequency FO. ．． E...Detection output voltage (constant amplitude)
f...Resolver excitation frequency (ω=2πf), △
f... Frequency change according to rotation speed, θe・
...Electrical angle of resolver rotor, K, lc'...
...Coefficient, t...Time.

Claims (1)

[Scope of Claims] 1. In a resolver having two-phase excitation windings spatially arranged at positions with a phase difference of 90 degrees in electrical angle and a detection winding for detecting the rotational position of the rotor, A rotational speed detection method characterized in that the frequency difference between the excitation signal applied to the excitation winding of the resolver and the phase modulation output signal of the detection winding obtained corresponding to the electrical angle rotor is extracted and used as a speed signal. . 2 When n is a positive integer in electrical angle spatially, 2π/n
In a resolver having n-phase excitation windings arranged at positions with different phases and a detection winding for detecting the rotational position of the rotor, the excitation signal applied to the excitation winding of the resolver and the electrical angle A rotational speed detection method characterized in that a frequency difference between phase modulated output signals of detection windings obtained corresponding to a rotor is extracted and used as a speed signal.