JPS5854758B2 - Torque detection device for polyphase alternating current machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a torque detection device for a polyphase alternating current machine.

Conventionally, in DC machines with constant field compensation windings, torque can be easily detected by detecting the armature current, but in the case of polyphase AC machines, torque cannot be detected accurately. There is no satisfactory torque detection device.

Another possibility is to detect the stress on the rotating shaft of the alternator and convert it into torque, but this method involves introducing into the calculation a complex relative relationship between the twist of the rotating shaft and the moment of inertia. Therefore, it is extremely difficult to convert the torque, making it impossible to accurately detect the torque.

In order to overcome the above-mentioned difficulties, the inventor conducted extensive research and found that by configuring the arithmetic circuit shown in FIG. 1, it was possible to detect the torque of the alternating current machine more or less accurately.

That is, terminal voltage detectors ■D1 and ■D2 are connected between the u-v phase and the vw phase of the three-phase alternating current machine G, current detectors ID and ID2 are connected to the U-phase conductor and the ■phase conductor, and the terminals Voltage detector vD1. (2) The outputs of D2 and current detectors ID1 and ID2 are supplied to an electromotive force calculator ED to calculate the electromotive force Euv between the uv phases and the electromotive force EVW between the vw phases.

Further, the u-v interphase electromotive force Euv calculated by the electromotive force calculator ED and the current Iu detected by the U-phase current detector ID are supplied to the multiplier M1, and the multiplied product E
uv and Iu are supplied to one input terminal of adder A1.

On the other hand, U-phase and V-phase current detectors ID1. The detection outputs Iu and Iv of ID2 are supplied to the adder A2, and the added value Iu+Iv=-Iw obtained from the output terminal is multiplied by the electromotive force Evw between the v - w phases calculated by the electromotive force calculator ED. The multiplied product Evw・(−
I w ) to the other input terminal of adder A.

Therefore, in the adder A1, the input Euv·Iu supplied to one input terminal and the input Evw·(-Iw) supplied to the other input terminal are added, and the result is shown in the following formula % Formula % (1) The instantaneous power P obtained by the double dynamometer method is taken out from the output terminal of the adder A1.

Further, a speed detector SD is connected to the rotating shaft of the alternating current machine G, and the rotational speed N is taken out from its output terminal.

In this way, by supplying the instantaneous power P and the rotational speed N to the divider and dividing the instantaneous power P by the rotational speed N, the instantaneous torque T can be calculated.

The terminal voltage Vu v obtained from the output terminal of each component in the detection process when the torque of a non-commutator motor is detected using the torque detection device configured as described above.
+Vvw, current Iu, -Iw, electromotive force Euv, EV
W1 Product of electromotive force and current E u v r I u +E
The waveforms of vw·(-■w), detected torque T, etc. are shown in FIG. 2 a, b, c, d, e, f2g, respectively.

The detected torque T shown in FIG. It turns out that it can be detected.

However, in the case of the above-mentioned torque detection device, the torque is calculated by dividing the instantaneous power P by the rotational speed N, and the divider generally cannot divide by zero or a negative value. Therefore, there is a problem in that the torque cannot be calculated when the rotational speed is zero or when the rotation is reversed.

Therefore, as a result of further research and ingenuity, the inventor found that
A magnetic flux calculator is provided to calculate the magnetic flux from the electromotive force, and the obtained magnetic flux is multiplied by the phase current using a multiplier to calculate the product of the current and magnetic flux of each phase. By configuring the arithmetic circuit to add the products of It was discovered that the problems of the above were solved all at once.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a torque detection device for a polyphase alternating current machine that can accurately detect torque regardless of the rotational direction with a simple configuration.

To achieve this object, the present invention provides an electromotive force calculator that calculates an electromotive force from the terminal voltage and current of an alternating current machine, and a magnetic flux calculator that calculates magnetic flux by integrating the electromotive force obtained by the electromotive force calculator. a multiplier that multiplies the magnetic flux obtained by the magnetic flux calculator and each phase current, and an output generator that generates a torque detection output by adding the products of the magnetic flux and current of each phase obtained by the multiplier. It is characterized by consisting of.

Next, a torque detection device for a polyphase alternating current machine according to the present invention will be described in detail below with reference to the accompanying drawings.

In FIG. 3, reference numeral 10 indicates a three-phase alternating current machine, and terminal voltage detectors 12uv and 12vw are connected between the u-'-v phase and the v-w phase of this three-phase alternating current machine 10,
Current detectors 14u and 14 are installed on the U-phase conductor and ■ phase conductor.
Connect v.

Current detector 14u. 14v each output terminal is connected to an input terminal of an inverting amplifier 16 and a terminal voltage detector 12u
v, 12vw and the output terminals of the current detectors 14u, 14v are connected to the input terminal of the electromotive force calculator 18, and the u - v calculated by the electromotive force calculator 18 is connected.
An output terminal for taking out the phase-to-phase electromotive force Euv and the vw phase-to-phase electromotive force Evw is connected to the input terminal of the magnetic flux calculator 20.

Therefore, the output terminal for taking out the magnetic flux Φvw interlinking with the V-phase and W-phase windings calculated by the magnetic flux calculator 20 and the output terminal of the U-phase current detector 14u are connected to the input terminal of the multiplier 22, and the magnetic flux calculation The output terminal for taking out the magnetic flux Φwu interlinking with the W-phase and U-phase windings calculated by the device 20 and the output terminal of the V-phase current detector 14v are connected to the input terminal of the multiplier 24, and The calculated U phase,
The output terminal for taking out the magnetic flux Φuv interlinking with the V-phase winding and the output terminal of the inverting amplifier 16 are connected to the input terminal of the multiplier 26 .

In this way, the respective output terminals of the multipliers 20, 22, 24 are connected to the inverting amplifier 28, and the inverting amplifier 2
8 is connected to the detection output terminal P.

Next, the operation of the apparatus of the present invention constructed as described above will be explained by exemplifying the case where a three-phase non-commutator motor is used as the multiphase alternating current machine.

Therefore, the terminal voltage detector 12uv between the n-v phase and between the v-w phase.

12vw is the terminal voltage V u V with the waveform shown in Figure 4g.
+Vvw is supplied to the electromotive force calculator 18, and the U-phase and V-phase current detectors 14u and 14v output the U-phase and V-phase currents Iu and Iv of the waveforms shown in FIG. The case where the signal is supplied to the arithmetic unit 18 and the multipliers 22 and 24 will be explained.

First, the detected currents Iu and I from the current detectors 14u and 14v.
When v is supplied to the inverting amplifier 16, these inputs Iu
, Iv are added and inverted, and from its output terminal -(
Iu + Iv) = Iw, that is, W phase current Iw (Fig. 4d
) is applied to one input terminal of the multiplier 26.

Terminal voltage detector 12uv, 12vw and current detector 1
Detection outputs from 4u and 14v Vu VI Vv
lol.

When Iu and Iv are supplied to the electromotive force calculator 18, the voltage drop due to the winding resistance and the induced voltage due to leakage reactance are removed from the terminal voltages Vuv and Vvw, and the phase-to-phase electromotive force Euv yEvw shown in FIG. 4e is output. It is supplied from the terminal to the input terminal of the magnetic flux calculator 20.

The input supplied to the magnetic flux calculator 20 is integrated, and the magnetic flux Φu V rΦVW+Φwu (
Figure 4f) is taken out.

The magnetic fluxes ΦuvtΦvw and Φwu indicate magnetic flux components interlinking with the U-phase V-phase winding, the V-phase W-phase winding, and the W-phase U-phase winding, respectively.

Among these magnetic fluxes, the magnetic flux Φvw is supplied to the multiplier 22 and multiplied by the other input Iu to output the product Iu·Φvw, and the magnetic flux (Dwu is supplied to the multiplier 24 and multiplied by the other input Iv). The magnetic flux Φuv is supplied to the multiplier 26, where it is multiplied by the other input Iw and the product Iw·Φuv is output.

In this case, for example, if we consider the torque expressed by the product Iu·Φvw, in FIG. This action generates a clockwise rotational force on the stator winding, that is, a torque that drives the rotor counterclockwise.

Now, assuming that the torque acting on the rotor in the clockwise direction is a positive torque, and the torque generated by the U-phase current Iu is Tu, the product Iu and Φvw are expressed by the following equation.

Similarly, if the torque generated by the V-phase current Iv and the W-phase current Iw is T v rTw, then the product Iv・Φ
wu and the product Iw・Φuv are expressed by the following, and the above (
4) Torque −Tu shown in formulas (5) and (6)
, -Tv, -Tw have the waveforms shown in g + h + t in Fig. 4.

The outputs of such multipliers 22, 24, 26 -Tu, -
Tv and -Tw are supplied to the inverting amplifier 28, and as shown in the following equation, these inputs are added and inverted, and the torque T shown in FIG. 4J is taken out from the output terminal P.

As described above, in the device of the present invention, since no divider is used for calculation, torque can be detected regardless of the rotation direction, and the detected torque T can be calculated as described in (3) above.
This agrees with the average torque Tm calculated from the theoretical formula shown in the equation, indicating high accuracy.

In the above embodiments, a non-commutator motor was used as an example of a multiphase alternating current machine, but it can also be applied to general induction machines and synchronous machines with three or more phases. The waveform of the phase current may be a sine wave or a rectangular wave.

According to the device of the present invention, with a simple configuration, torque can be accurately detected regardless of the direction of rotation, and the device has a very large effect in contributing to improving the control technology of polyphase alternating current machines.

Although the preferred embodiments of the present invention have been described above, it goes without saying that various design changes can be made without departing from the spirit of the present invention.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a configuration example of a torque detection device for a polyphase alternating current machine, Fig. 2 is a waveform diagram showing the operation of the device shown in Fig. 1, and Fig. 3 is a polyphase alternating current machine according to the present invention. FIG. 4 is a block diagram showing an embodiment of the torque detecting device of FIG. 10...3 phase AC machine, 12uv, 12vw...
...Terminal voltage detector, 14u, 14v...
Current detector, 16...Inverting amplifier, 18...-
...Electromotive force calculator, 20...Magnetic flux calculator, 2
2, 24.26... Multiplier, 28...
Inverting amplifier.

Claims (1)

[Claims] 1. An electromotive force calculator that calculates the electromotive force from the terminal voltage and current of the alternating current machine, a magnetic flux calculator that calculates the magnetic flux by integrating the electromotive force obtained by the electromotive force calculator, and a magnetic flux calculator that calculates the electromotive force obtained by the magnetic flux calculator. A multiplier comprising: a multiplier that multiplies the magnetic flux and the current of each phase; and an output generator that generates a torque detection output by adding the products of the magnetic flux and current of each phase obtained by the multiplier. Torque detection device for phase alternator.