JPS6226272B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a phase information detection device for induced voltages of each phase that is useful when controlling the speed of a multiphase synchronous motor.

Conventionally, when controlling the speed of a rotary synchronous motor or a linear synchronous motor, the induced voltage of each phase has been determined using each phase voltage and each phase current output from a power conversion device. However, the induced voltage of each phase generally contains many harmonic components, and a low-pass filter has been used to remove these harmonic components. However, conventional synchronous motors have the drawback that these low-pass filters add delay time to the induced voltage of each phase, making it impossible to realize speed control with good responsiveness. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a phase information detection device for a synchronous motor that is free from the above-mentioned drawbacks.

This invention will be explained below.

In FIG. 1 showing an embodiment of the present invention, a phase voltage 1 output from a power conversion device (not shown) is shown.
U, 1V, 1W and phase currents 2U, 2V, 2W are input to the induced voltage calculation circuits 3U, 3V, 3W, respectively, and the outputs are induced voltages 4U, 4V, 4W.
are input to Betssel type low-pass filters 5U, 5V, and 5W, each having a characteristic that the delay time is constant, and their outputs are input to a three-phase full-wave rectifier circuit 7, and are also input to divider circuits 9U, 9V, and 9W, respectively. It is becoming more and more common. Therefore, the output of the three-phase full-wave rectifier circuit 7 is also input to the amplifier 13,
The output voltage 8a is input to comparison circuits 11U, 11V, and 11W together with the outputs of division circuits 9U, 9V, and 9W, respectively.

In such a configuration, its operation is shown in Figure 2A.
-D and the time charts of FIGS. 3A-D.

First, a U-phase voltage 1U and a U-phase current 2U output from a power converter (not shown) are input to an induced voltage calculation circuit 3U, and the output of the induced voltage 4U, which includes harmonic components, is input to a Betzel type low-pass filter 5U. (Figure 2A and Figure 3A). Since the delay characteristic of the Betzel type low-pass filter 5U is constant, the delay time Td is constant regardless of the frequency f of the induced voltage 4U (Fig. 2B
and Fig. 3B), delayed phase angle θd of output voltage 6U
is proportional to the frequency as shown in the following equation.

θd={Td/(1/f)}×2π=2πfTd
(rad) ......(1) Now, in the range where the relationship sinθd≒θd holds, sin (±θd) = ±θd = ±2πfTd ......(2) and the peak value of the output voltage 6U is the frequency Since it is proportional to f, when the voltage 6U is divided by the output voltage 8 of the three-phase full-wave rectifier circuit 7 by the dividing circuit 9U, a normalized induced voltage 10U with a constant peak value is generated (Fig. 2C and 3 C). Therefore, the three-phase full-wave rectified voltage 8 is multiplied by 2πTd by the amplifier 13 (formula
(2)), when this output voltage 8a is input as a reference voltage to the comparison circuit 11U and compared with the normalized induced voltage 10U, a rectangular wave 12U whose phase matches the fundamental wave component of the induced voltage 4U is obtained (see Fig. 2). D and Figure 3 D). Hereinafter, such phase information detection processing is similarly executed for the V-phase induced voltage of 4V and the W-phase induced voltage of 4W.

As explained above, according to the phase information detection device of the present invention, phase information of induced voltage without delay time can be generated even if a Betssel type low-pass filter is used, and speed control of a rotary synchronous motor or a linear synchronous motor can be performed. The response characteristics can be significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the phase information detection device of the present invention, FIGS. 2A to 3D, and FIG. 3A.
~D are time charts for explaining the respective operations. 3U, 3V, 3W...Induced voltage calculation circuit, 5
U, 5V, 5W... Betssel type low pass filter, 7... Full wave rectifier circuit, 9U, 9V, 9W...
Division circuit, 11U, 11V, 11W...comparison circuit, 13...amplifier.

Claims (1)

[Scope of Claims] 1. A plurality of induced voltage calculation circuits that calculate each phase induced voltage from each phase voltage and each phase current of a power converter, and a plurality of induced voltage calculation circuits that are coupled to these induced voltage calculation circuits and calculate each phase induced voltage. a plurality of Betzel-type low-pass filters that respectively remove harmonic components contained in voltage; a rectifier circuit that is coupled to these Betzel-type low-pass filters and generates a multiphase full-wave rectified voltage; the plurality of Betzel-type low-pass filters; a plurality of voltage division circuits that are coupled to the rectifier circuit and normalize the induced voltages of each phase; and a plurality of voltage division circuits that are coupled to these voltage division circuits and convert each of the phase normalized voltages into the multiphase full-wave rectified voltage. is compared with a predetermined reference voltage proportional to the product of and the delay time of the Betzel type low-pass filter, and
A phase information detection device for a synchronous motor, comprising a plurality of induced voltage shaping circuits that output phase information.