JPH0139527B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting position and velocity by time-division of detected signals from a detection winding of one resolver.

Conventionally, among brushless resolvers, there is a rotary transformer type resolver that is excited by alternating current, but since this is not excited by direct current, it is limited to detecting position only, and cannot detect speed at the same time.

Therefore, it was necessary to use a separate speed detection device in combination.

On the other hand, as a method for simultaneously detecting position and velocity from a brushless resolver, for example, the present inventor proposed a method previously proposed in Japanese Patent Application No. 52-139343
There is a precedent example of an inductor type resolver (71671), which uses DC and AC superimposed excitation.

Therefore, the present invention provides a time-division detection method for position and speed that can be excited using only alternating current and simultaneously detect position and speed, and that can be applied to either a rotating transformer type or an inductor type resolver. Its purpose is to

Usually, a resolver detects only the position, and the speed is detected by a DC tachogen. Recently, there has been a trend toward brushless servo motors, and DC tachometers are also becoming brushless.
It is troublesome to separately provide a brushless DC tachometer outside the resolver, and there is a desire to obtain speed signals only from the resolver if possible.

Therefore, in the previous example, a brushless inductor resolver was used to perform this excitation with a current that is a superimposition of direct current and high-frequency alternating current, detect the superimposed voltage of velocity em and position voltage from this detection winding, and separate this using a filter. The speed and position signals are obtained at the same time.

However, the most suitable detector for servo motors is
Ideally, it would be an electromagnetic machine with the same structure as a motor.
This is considered to be a resolver. Using a resolver as a highly reliable detector that can withstand harsh environments and usage conditions and has appropriate accuracy and responsiveness, we aim to obtain not only position but also velocity signals.
In other words, based on the principle that the resolver is a two-phase synchronous machine, it is clear that not only the position but also the speed can be detected.The present invention embodies a method for detecting the position and speed in a time-division manner using a single resolver.

Now, embodiments of the present invention shown in the drawings will be described.

FIG. 1 is a diagram showing the winding distribution of the resolver.

This resolver has an excitation winding W and a two-phase detection winding.
Consists of W〓 (α phase) and W〓 (β phase). When an excitation current i is passed through the excitation winding W, and the angle θ formed by the winding axes of the excitation winding W and the α-phase winding W〓, em (em) generated in the α-phase winding W〓 and the β-phase winding W〓 is power) and voltage e〓,
If e〓, then e〓=Mcosθdi/dt−iMsinθ・ν (1 equation) where M is the maximum value of mutual inductance between excitation winding W and two-phase winding W〓 (or W〓), ν=
dθ/dt.

FIGS. 2a and 2b are waveform diagrams of the excitation current to the resolver and its detected voltage according to the present invention.

When the excitation winding W is excited with a symmetrical trapezoidal wave current as shown in FIG. 2a, a voltage eα is generated in the α-phase winding W as shown in FIG. 2b.

At the slope portion of the excitation current i, di/dt≠0. Further, the average value of the excitation current i is zero. (1st formula)
Although the second term -iMsinθ・ν occurs as an instantaneous value, its average value is 0, and is suppressed by the filter effect of the frequency characteristics of the amplifier provided at the subsequent stage.
Therefore, only the first term remains. Therefore, at the slope portion of the excitation current i, the first term of (Equation 1) e〓 _p =Mcosθ·2I/T (Equation 2) where I is the maximum value of i.

appears, and in the flat part of the excitation current i, di/dt=0
Therefore, the second term e〓 _s = −IMsinθ·ν of (1st equation) appears (3rd equation).

If only time periods T ₁ and T ₂ are taken out, the position modulation voltage will be
e〓 _p is obtained, and if only time periods T ₂ and T ₄ are extracted, the speed modulation voltage e〓 _s can be obtained.

It is also clear that voltages e〓 _p and e〓 _s are obtained in the β-phase winding W〓.

e〓 _p = Msinθ・2I/T ... (4th equation) e〓 _s = IMcosθ・ν ... (5th equation) By the way, since the frequency of the excitation current i is set to several kilohertz or more, it is necessary to use a rotating transformer. This trapezoidal wave excitation can also be applied to brushless resolvers.

FIG. 3 is a block diagram of one embodiment of the present invention.

1 is a power supply, 2 is a trapezoidal wave current generator that generates the symmetrical trapezoidal wave shown in Fig. 2a, and 3 is a resolver.
is its rotation axis, 4 is a clock oscillator, 5 is a timing generator, 6, 7 are synchronization suppression circuits, 8, 9, 1
2 and 13 are amplifiers, and 10, 11, 14, and 15 are synchronous rectifier circuits.

The excitation winding W of the resolver 3 is excited by the trapezoidal wave current generator 2 (for example, the trapezoidal wave is 10 KC/S).

The detection (α phase, β phase) modulation detection voltages e〓, e〓 generated in the windings W〓, Wβ are amplified by amplifiers 12, 13, and the timing generator 5 (for example, clock oscillator 40KC/S, timing generator 10KC/S) from timing T ₁ , T ₃ (period T 1 , T ₃ in Figure 2 a, b)
By performing synchronous rectification in the synchronous rectification circuits 14 and 15 at T ₃ ), position signal voltages υ〓 _p and υ〓 _p are obtained.

On the other hand, the modulation detection voltages e〓, e〓 are at timing T ₁ ,
This is prevented by preprocessing through suppression circuits 6 and 7 that suppress only the position modulation voltage in synchronization with _T3 , and the detected voltage that has passed through the suppression circuits 6 and 7 is sent to amplifiers 8 and 9.
The speed signal voltages υ〓 _s , υ〓 _s are amplified and synchronously rectified in the synchronous rectifier circuits 10 and 11 at timings T ₂ and T ₄ (representing the periods T ₂ and T ₄ in FIG. 2 a and b).
get.

The speed signal (modulation detection) voltages υ〓 _s , υ〓 _s are about 1/100 or less of the position signal (modulation detection) voltage, and if the modulation detection voltage is amplified without this preprocessing, the amplifier will saturate, which is undesirable.

The speed ν is obtained by performing the following calculation.

ν=(2/T・υ _p ² ) (υ〓 _s・υ〓 _p −υ〓 _s・υ〓 _p
)
...(Equation 6) Here, υ _p is the amplitude of the position signal voltage and is constant, that is, υ _p =√〓 _p ² +〓 _p ² .

There are two types of brushless resolvers: an inductor resolver and a conventional resolver using a rotating transformer. The former is capable of direct current excitation and therefore can be subjected to superimposed direct current and alternating current excitation, but the latter is not capable of direct current excitation.

The trapezoidal wave excitation used in the time-division detection of the present invention is
It is applicable to either of these resolvers. Commercially available brushless resolvers are rotary transformer type (latter)
Therefore, although orthogonal superimposed excitation was not possible, the method of the present invention can be applied. The brushless DC tachometer on the market consists of this magnetic pole position detector that uses an AC tachometer and a hall, but the one of the present invention is not only simple in structure, but consists of only one resolver. It also serves as a position detector.

Another method for obtaining the speed signal voltage is to differentiate the position signal voltage using a differentiating circuit. However, this method magnifies the noise and increases the S/N
Since this degrades the ratio, it is necessary to perform sufficient pretreatment with a filter, which increases the time delay, which is undesirable.

Digitalization is also possible as another embodiment of this embodiment. In other words, in this time-division detection method of position and velocity using trapezoidal wave excitation, the voltages of the position vector and velocity vector are sampled and detected, so these sample values are A/D converted and digitally calculated to calculate the velocity. The method for finding ν is also easily established.

[Brief explanation of drawings]

Figure 1 is a resolver winding distribution diagram, Figure 2 a, b
3 is a waveform diagram of an excitation current to a resolver and its detection voltage according to the present invention, and FIG. 3 is a block diagram showing the configuration of an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Power supply, 2... Trapezoidal wave current generator, 3... Resolver and 30 is its rotating shaft, 4... Clock oscillator, 5
...timing generator, 6,7...synchronization suppression circuit,
8, 9, 12, 13...Amplifier, 10, 11, 1
4, 15...Synchronous rectifier circuit, W...Excitation winding of resolver 3, W〓, W〓...Detection winding of resolver 3 (α
phase, β phase).

Claims (1)

[Scope of Claims] 1. A trapezoidal wave alternating current generator, a resolver having a winding excited from this current generator, and a two-phase detection winding, and a voltage generated in each phase winding of the current generator. The present invention uses a resolver characterized in that it is equipped with a device that synchronously rectifies the slope portion and the flat portion of the trapezoidal waveform alternating current from the device, respectively, and obtains a two-phase position signal and a speed signal voltage from the synchronous rectifier. Time division detection method for position and velocity. 2. A position and position system using a resolver according to claim 1, characterized in that an arithmetic device is provided for multiplying each position signal voltage and each speed signal voltage of different phases and deriving the difference between the two. Time division detection method for speed. 3. A synchronization suppression circuit that synchronizes with the slope portion of the trapezoidal waveform alternating current is provided upstream of a synchronous rectifier that synchronously rectifies the modulated detection voltage corresponding to the flat portion of the trapezoidal waveform alternating current. A time-division detection method of position and velocity using the resolver described in scope 1.