JPS6124319A - Detector for control system input - Google Patents

Abstract

PURPOSE:To eliminate or extract a synchronizing frequency component in high speed with high accuracy by constituting a control system input detector with a synchronizing frequency generator comprising a PLL and a V/F circuit etc., and a frequency control filter comprising a switched capacitor filter, etc. CONSTITUTION:A signal fi to be measured outputted from an inverter 13 is fed to the frequency control filter 11 and a prescribed frequency component is eliminated (or extracted) based on a filter clock fc from the variable frequency oscillator 16 fed to the frequency control filter 11. When an output voltage and frequency of the inverter 13 are changed, the oscillating frequency fc of the variable frequency oscillator 16 is controlled by a control circuit (not shown in figure) to which an output of the frequency control filter 11 is fed, the time constant of the frequency control filter 11 is changed to control the inverter 13 with the output of an inverter gate pulse generating circuit 17.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a control system input detection device for detecting and controlling an output component in, for example, a power conversion device or a motor drive device, and particularly relates to a control system input detection device for detecting and controlling an output component in a power conversion device or a motor drive device, etc. It is used in devices that contain variable frequency components.

[Technical background of the invention and its problems] In general, in the control of power converters or motor drive devices, the AC output is rectified and converted into specific frequency components.
In order to remove Rizzol from the output of a DC speed generator,
All low-pass filters with large time constants are inserted.

By the way, when removing or extracting a specific frequency component from an AC output waveform, CVCF (Cons LantV
Altage Con5tant Frequency
) If the fundamental frequency is constant, such as in an inverter, a normal filter can be used, but VVVF (Variable
e VoltageVariable Frequency
cy) When the fundamental wave frequency changes as in an inverter, the output is rectified and converted into a fundamental wave component or the like.

However, when the waveform distortion is large, the error becomes large.

On the other hand, when extracting only the DC component from a DC output waveform that includes AC, for example, when extracting only the DC component from a DC that includes ripples due to a commutator, such as in a DC speed generator,
Generally, a low-pass filter is used, but its time constant must be made longer in order to remove ripples at low speeds.

For this reason, at high speeds, the time constant of the filter becomes longer than necessary, which increases control delay and reduces control performance.

[Purpose of the invention]

This invention was made in view of the above circumstances,
The object of the present invention is to provide an excellent control system input detection device that has a relatively simple configuration and can remove or extract synchronous frequency components with high accuracy and high speed.

[Summary of the invention]

That is, in this invention, in order to achieve the above object, PLL (Phase Locked Loo
p).

V/F (Voltar Ha to Frequency)
A control system input detection device is constructed by a synchronous frequency generator consisting of a y converter circuit, etc., and a frequency control type filter consisting of a switched carrier, 9-stage filter, etc.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. Figure 1 shows the basic principle.
is supplied to a frequency controlled filter 11 consisting of, for example, a switched capacitor filter, and the PL
The signal is supplied to a synchronous frequency generator No. 2 consisting of L, V/F circuits, etc.

A predetermined frequency component of the signal under test fi is extracted by the synchronous frequency generator 12, and a filter clock fc based on the extracted frequency is applied to the frequency controlled filter 1.
and its time constant is controlled. Then, an output signal f 2 from which a specific frequency is removed (or a specific frequency is extracted) is obtained from this frequency-controlled filter 12 .

Therefore, according to such a configuration, since the time constant of the frequency-controlled filter 1 is set based on the extracted frequency component, a filtering action according to the frequency can be obtained, and high precision and high speed can be realized.

Fig. 2 1d shows a YVVF inverter to which the present invention is applied. In the figure, 13 is an inverter, 14 is an inverter DC power supply that drives this inverter 13, and 15 is a load driven by the 13V of the inverter. The output of 13 is supplied to frequency controlled filter 11.

This frequency controlled filter 1-1 is supplied with the output of the 1jJi frequency oscillator 16, and this iEJ
The output of the variable frequency oscillator is supplied to an inverter gate pulse generation circuit 77VC. The output of the frequency control type filter 1 is supplied to a control circuit (not shown), and the output of this control circuit causes the oscillation output of the variable frequency oscillator 16 and the output of the inverter pulse generator 17 to be transmitted to the inverter 13. Dart pulse is controlled.

In the above configuration, the signal under measurement f output from the inverter 13 is supplied to the frequency controlled filter 1, and the filter clock fc from the variable frequency oscillator 16 supplied to the frequency controlled filter 1 is A predetermined frequency component is removed (or extracted) based on.

When the output voltage and frequency of the inverter 3 change, a control circuit (not shown) to which the output of the frequency control filter 1 is supplied controls the oscillation frequency fc of the variable frequency oscillator 16, and the frequency control filter 1 controls the oscillation frequency fc of the variable frequency oscillator 16. In addition to changing the time constant of 1, the inverter 13 is controlled by the output of the inverter gate pulse generating circuit NOR.

According to such a configuration, even if the fundamental wave frequency and voltage of the signal under test f. fluctuate, a specific frequency component can be removed or extracted from the AC waveform of the signal under test f1 with high precision and high speed.

FIG. 3 shows another embodiment of the invention, in which a PLL circuit 18 is used to generate the filter clock fc. In the figure, the same reference numerals are given to the same storage parts as in FIG. 2, and the explanation thereof will be omitted. That is, the signal to be measured fi from the inverter 3 is supplied to the frequency controlled filter 1, and is also supplied to the PI, L circuit 18.
supplied to Based on the filter clock fc output from the PLL circuit 18, the time constant of the frequency control type filter 1 is set.

Even in such a configuration, the same effects as in the above embodiment can be obtained.

FIG. 4 shows another embodiment of the invention,
This invention is applied to a DC speed generator. Here, in the case of a DC speed generator, a V/F circuit is used to generate the filter clock f 2 by utilizing the fact that the DC component of its output voltage and the ripple frequency are proportional to the rotation frequency. That is, the output of the DC speed generator 19 is supplied to the frequency controlled filter 1 as the signal to be measured f, and is also supplied to the v/F circuit 20. Then, the output voltage of the V/F circuit 20 is supplied to the frequency-controlled filter 11 as a filter clock fc, and its time constant is controlled.

With this configuration, when extracting only the DC component from the DC component including ripples caused by the commutator, the time constant of the filter was longer than necessary, resulting in delayed control), or too short, resulting in insufficient filter action. Highly accurate and high-speed filtering can be achieved.

〔Effect of the invention〕

As described above, according to the present invention, an excellent control system input detection device can be obtained which can remove or extract a synchronous frequency component with high accuracy and high speed while having a relatively simple configuration.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the basic principle of a control system input detection device according to an embodiment of the present invention, and FIGS. 2 to 4 are diagrams for explaining other embodiments of the invention, respectively. It is. DESCRIPTION OF SYMBOLS 11... Frequency control type filter, 12... Synchronous frequency generator, fi... Signal under test, fc... Filter clock, fo... Output signal. Applicant's Representative Patent Attorney Takehiko Suzue Figure 1 Figure 2 Section 3 Figure 4

Claims (1)

[Claims] a frequency controlled filter to which alternating current or direct current containing an alternating current component is supplied as a signal to be measured; and a filter clock which is supplied with the signal to be measured and which corresponds to a signal of a predetermined frequency component extracted from the signal to be measured; A detection circuit for control system input, comprising a synchronous frequency generator that sets a time constant of the frequency-controlled filter, and obtains a signal obtained by removing a specific frequency component synchronized with the signal under test. .