JPH0593747A - Power analyzer - Google Patents

Abstract

(57) [Summary] (Corrected) [Purpose] To enable waveform analysis of the fundamental wave component and carrier wave component of the input measured signal. A power analyzer apparatus is provided with a first filter unit 2 in which a cutoff frequency for passing at least a predetermined frequency band of an input measured signal is variable, and S / H and A for digitally converting a signal passing through the filter unit 2. / D converter 3
A memory 4 for storing digitally measured data to be measured, a second filter section 6 for passing the fundamental wave frequency of the input measured signal, and a fundamental wave frequency of a carrier component included in the measured signal. The third filter unit 16 that passes the signal, the second switching unit 17 that switches the signals that have passed through the filter units 6 and 16, and the cutoff frequency of the first filter unit 2 is set based on the switched signal, and the conversion is performed. The PLL unit 8, the storage control unit 5, and the storage unit 5 and C which synchronize the timing control of the unit 3 and the memory 4 by the PLL synchronization system or by the fixed synchronization system by the oscillation frequency of the oscillator 9.
And PU18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for measuring the electric power of an inverter type power supply and the like. The present invention relates to a power analyzer device that enables waveform analysis.

[0002]

2. Description of the Related Art In recent years, as semiconductor power conversion devices (inverter type power supplies) have been used in many devices, more and more measurement data can be processed easily and quickly to measure the power, and further input. A power measuring device (power analyzer device) has been proposed that can analyze the frequency contained in the signal under measurement.

An example of this power analyzer device is shown in FIG. 9, which has an input section 1 for performing necessary processing on an input measured signal, and an input measured signal via the input section 1. A first filter unit (for example, an anti-leasing filter) 2 having a variable cutoff frequency passing through a predetermined frequency band, and a signal passing through the first filter unit 2 is sampled at a predetermined frequency, and the sampled value S / H and A / D converter 3 for digitally converting
A memory (RAM) 4 for storing the digitally measured data to be measured; and a cutoff frequency of the first filter unit 2 so that aliasing distortion due to the A / D conversion does not occur, and the S / H And a storage controller 5 for controlling the timing of the A / D converter 3 and the memory 4.

Further, this power analyzer apparatus has a second filter (low-pass filter; 5 Hz to 1 Hz) for shaping the waveform through the frequency components in the fundamental wave range of the input measured signal.
50 Hz) 6, the frequency measuring section 7 for measuring the frequency of the fundamental wave by the signal passed through the second filter, the S / H and A / D converting section 3, and the timing of the memory 4 with respect to the fundamental wave. A PLL (Phase Locked Loop) unit 8 that synchronizes with the frequency, an oscillating unit 9 that oscillates a pulse signal with a preset frequency, and the S / S method using a PLL system or a fixed system when capturing the digitally measured data. Since the timings of the H and A / D converter 3 and the memory 4 are synchronized with the input measured signal,
A switching unit (analog switch) 10 for switching between the pulse signal from the L unit 8 and the pulse signal from the oscillator 9 and outputting to the storage control unit 5 is provided.

Therefore, by switching the switching unit 10, the power analyzer apparatus is set to the PLL synchronous mode or the fixed clock mode, the input measured signal is digitally converted according to each mode, and the digitally converted measured data is stored in the memory 4. Memorized in.

Further, at least the memory section 4, the storage control section 5, the frequency measuring section 7 and the oscillator 9 are connected to a bus line (address bus, data bus) 12 of a CPU 11 which is the main control of the power analyzer apparatus.
The CPU 11, the memory 4, the storage controller 5,
The frequency measuring unit 7 and the oscillator 9 are controlled, for example, the cutoff frequency of the first filter unit 2 is determined according to the measurement frequency of the frequency setting unit 7, and based on the measured data read from the memory 4. Calculation of RMS and power values of voltage and current, and waveform analysis of harmonics.

The bus line 12 receives the data to be measured, calculates the power value, analyzes harmonics,
A memory (ROM / RAM) 13 that stores a control program for displaying the calculation and analysis results and stores the data of the calculation and analysis results, and a display that displays the calculation and analysis results. The instrument 14 and the key unit 15 for performing the operation of calculating the voltage, current, and power from the input measured signal and analyzing the harmonics thereof are connected.

Further, when the power analyzer device has one channel, at least the input section 1 has a unit configuration of one set of the voltage and current to be measured. Therefore, when the power analyzer device has three channels. , That unit becomes three. Corresponding to the configuration of the input unit 1, the first filter unit 2, S / H and A /
The configurations of the D conversion unit 3 and the memory 4 are changed.

Here, assuming that the signal to be measured is input to the input section 1 and the key analyzer 15 is operated to set the power analyzer device having the above-described configuration to the PLL synchronization mode, the switching section 10 in the CPU 11 operates. It is switched to the PLL unit 8 side.

Then, when the fundamental wave component of the input measured signal is digitally converted and the digitally measured data is taken in, the cutoff frequency of the first filter section 2 is based on the fundamental frequency of the input measured signal. The timing of the S / H and A / D conversion section 3 and the memory 4 is set in accordance with the fundamental frequency of the input measured signal, so that the digitally converted measured data is accurately captured. In addition, based on the measured data taken in, not only the effective values of the voltage and current, the power value, etc., but also the harmonic analysis of the fundamental wave can be accurately performed.

On the other hand, when the power analyzer device is set to the fixed clock mode by operating the key portion 15,
The switching unit 10 is switched to the oscillator 9 side by the CPU 11.

Then, the fundamental wave component of the input measured signal is digitally converted in the fixed synchronous mode, and the digitally converted measured data is stored in the memory.

Therefore, as in the case of the PLL synchronous mode, more accurate data to be measured can be taken in by the input measured signal, and one cycle of the input measured signal (voltage, current) can be obtained to determine the power, etc. Not only that, it can also be used for waveform analysis of an input measured signal whose frequency is not constant.

[0014]

In the power analyzer device described above, for example, in the case of driving a motor, the fundamental wave (including harmonic components) is included in the secondary side voltage / current (signal to be measured) of the inverter type power supply. Not only is the carrier component included, but there is a problem in that the above-mentioned harmonic analysis function cannot separate and measure the carrier component.

That is, the carrier wave component is asynchronous with respect to the fundamental wave component, and the sampling frequency of the carrier wave component is determined in synchronization with the fundamental wave component.

Further, even with a general FFT analysis device, a frequency of 100 is generated between the fundamental wave and the carrier component.
Since there is a difference of about 1 to 10,000 times, setting the range so that the same carrier component can be analyzed enables good measurement of the same carrier component, but conversely the frequency resolution of the fundamental component deteriorates. However, the fundamental wave cannot be measured accurately.

Further, in the case of the FFT analysis device, there is a drawback that it becomes extremely expensive if the fundamental wave and the carrier wave are simultaneously measured.

The present invention has been made in view of the above problems, and an object thereof is to accurately analyze and measure not only a fundamental wave component (including a harmonic component) of an input measured signal but also its carrier component. An object of the present invention is to provide a power analyzer device that can be manufactured at low cost.

[0019]

In order to achieve the above object, the present invention provides a first filter section having a variable cutoff frequency passing at least a predetermined frequency band of an input measured signal, and the first filter section. S / H and A / D conversion section for sampling the signal passing through the filter section at a predetermined frequency and digitally converting it, a memory (RAM) for storing the digitally measured data to be measured, and the input measured signal. A second filter section that passes the fundamental frequency and this second
The cutoff frequency of the first filter unit is set based on the signal that has passed through the filter unit of
A PLL unit, a storage control unit, and a CPU that synchronize the timing control of the A / D conversion unit and the memory by the PLL synchronization system, or synchronize the timing control of the S / H and A / D conversion unit and the memory by the fixed system. In the power analyzer device which is provided with the same CPU and is capable of calculating the power value and the like based on the data taken in and analyzing the waveform of the fundamental wave component, the fundamental of the carrier wave component contained in the input measured signal is provided. A third filter unit for passing the wave frequency, and a switching unit for switching between the signal passing through the third filter unit and the signal passing through the second filter unit and outputting the signal to the PLL unit are provided. By switching parts,
The point is that not only the fundamental wave of the input measured signal but also its carrier wave can be measured.

[0020]

With the above configuration, when the input measured signal is digitally converted and taken in, the input measured signal is input to the first to third filter sections.

In this case, since the second filter section is a low-pass filter, the fundamental wave frequency of the input measured signal is passed, the third filter section is a programmable filter, and the pass frequency band thereof is the input filtered frequency band. Since the carrier frequency included in the measurement signal is set, the carrier frequency is passed.

At this time, until the PLL synchronization is established,
Since the measurement of the fundamental wave component takes more time than the measurement of the carrier wave component described above, the switching unit is set to the second mode in the CPU.
Can be switched to the filter side.

Then, the cutoff frequency of the first filter is set according to the fundamental wave frequency through the second filter section, and the cutoff frequency of the first filter is set to the fundamental wave frequency of the input measured signal.
Timing of the S / H and A / D converters and the memory is controlled in synchronization with L.

When the signal passed through the first filter section is digitally converted and the digitally converted data to be measured is stored in the memory in a predetermined number, the CP
At U, the switching section is switched to the third filter section side.

At this time, since the third filter section is key-operated or automatically set so as to pass the fundamental frequency of the carrier component, the cutoff frequency of the first filter is set to the carrier frequency. The components are set to pass through, and the timings of the S / H and A / D converters and the memory are controlled in synchronization with the fundamental frequency of the carrier wave of the input measured signal.

As a result, the carrier wave component contained in the input measured signal passes through the first filter section, the passed carrier wave component is digitally converted, and the digitally converted measured data is stored in the memory at a predetermined number. Remembered.

As described above, since not only the fundamental wave component of the input measured signal but also its carrier wave component are fetched into the memory, calculation of the effective values of the voltage and current and the power value by the input measured signal, Not only the waveform analysis of harmonics, but the waveform analysis of the carrier wave is possible.

In the description of the above operation, the case of the PLL synchronization mode has been described, but the same operation and effect can be obtained even in the fixed synchronization mode.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. In the figure, the same parts as those in FIG.

In FIG. 1, the power analyzer device includes a third filter section (programmable high-pass filter) 16 for shaping the waveform through the fundamental frequency of the carrier wave component contained in the signal under measurement input through the input section 1. ,
Second switching for switching between the fundamental wave of the input measured signal that has passed through the second filter section 6 and the fundamental wave of the carrier component that has passed through the third filter section 16 and outputting it to the frequency measuring section 7 and the PLL section 8. Section (analog switch) 17 and CP of FIG.
In addition to the function of U11, the pass frequency band of the first filter unit 2 is set based on the fundamental wave of the carrier measured by the frequency measuring unit 7, the PLL unit 8 and the like are controlled, and the memory 4
The CPU 18 for calculating the effective values of the voltage and the current and the power value based on the measured data stored in the CPU 18 and analyzing the waveforms of the harmonics and the carrier wave, and the same CP as the memory 13 of FIG.
A memory (ROM / RAM) 19 for storing the control program of U18, calculation, analysis result, and the like is provided.

Next, the operation of the power analyzer having the above configuration will be described with reference to the frequency spectrum diagram of FIG. 2 and the display screen diagrams of FIGS.

First, for example, in the case of driving a motor, the secondary side voltage and current of the inverter type power supply, that is, the signal under measurement contains a carrier wave (carrier wave) in addition to the fundamental wave component (including the harmonic component). (As shown in FIG. 2).

Here, when the PLL synchronization mode is set by operating the key portion 15, the CPU is operated as in the conventional example.
At 18, the first switching unit 10 is switched to the PLL unit 8 side, and the second switching unit 17 is switched to the second filter unit 6 side. That is, the frequency of the fundamental wave of the input measured signal is low, and it takes time to achieve PLL synchronization.

In this case, as described in the conventional example, the fundamental wave component of the input measured signal is digitally converted, and the digitally converted measured data is stored in the memory 4.

Subsequently, when the required number of the measured data is fetched, the second switching section 17 is switched to the third filter section 16 side by the CPU 18. When the operation of measuring the carrier component of the input measured signal is performed by the key unit 15, the second switching unit 17 is switched to the side of the third filter unit 16 to perform the measurement operation of the fundamental wave of the carrier component. You may do it.

Then, for example, if the carrier wave frequency of the inverter type power supply is already set in the key section 15, the third filter section 16 in the CPU 18 allows the carrier wave frequency (input carrier wave of the measured signal to be measured) to pass therethrough. As described above, the third filter unit 16 outputs the fundamental wave of the carrier (shown by the chain double-dashed line in FIG. 2).

Further, since the fundamental wave of this carrier is input to the PLL unit 8 and the frequency setting unit 7 via the second switching unit 17, the cutoff frequency of the first filter unit 2 is determined, and The PLL unit 8 and the storage control unit 5 are controlled.

In the storage control section 5, the cutoff frequency setting of the first filter section 2 is controlled, and the timings of the S / H and A / D conversion section 3 and the memory 4 are controlled. Further, in the PLL unit 8, the timings of the S / H and A / D conversion unit 3 and the memory 4 are synchronized with the fundamental wave of the carrier wave of the input measured signal by the PLL synchronization method. The carrier component of the signal is digitally converted, and the digitally measured data is stored in the memory 4.

In this way, the memory 4 stores not only the fundamental wave component (including the harmonic component) of the input measured signal but also the measured data of the carrier component. Based on these measured data, the CPU 18 calculates the voltage, current effective value, and power value by the input measured signal,
Harmonic analysis and carrier waveform analysis are performed.

Since the calculation result and the waveform analysis result are stored in the memory 19, as shown in FIGS. 3 and 4, the display control of the CPU 18 causes the display 14 to display the stored calculation result and analysis result. Can be displayed numerically. The resulting numerical values can also be displayed in a spectral format, as shown in FIGS. 7 and 8.

Furthermore, not only the analysis results of the fundamental wave component and the carrier wave component data of the input measured signal are separately displayed, but also the analysis results are displayed on the same screen as shown in FIG. By continuously displaying, waveform analysis can be facilitated. Further, as shown in FIG. 6, the analysis results of the above two components can be displayed in a spectral format.

As described above, not only the fundamental wave component (harmonic component) of the input measured signal but also the carrier wave component can be analyzed, and the measurement result and the waveform analysis result are displayed in numerical or spectral format. Therefore, for example, in the case of driving a motor, it is possible to analyze noise and noise more accurately.

Further, in the above-mentioned power analyzer, only the third filter section 16 and the second switching section 17 are added and the control program of the CPU 18 and the like are added, which is not expensive as in the FFT apparatus. It can be done cheaply.

[0044]

As described above, according to the power analyzer of the present invention, at least the first filter section having a variable cutoff frequency for passing the predetermined frequency band of the input signal under measurement and the first filter section are provided. An S / H and A / D conversion section for digitally converting the signal passed through the filter section, a memory for storing the digitally measured data, and a second filter section for passing the fundamental frequency of the input measured signal. , A third filter section for passing a fundamental frequency of a carrier wave component included in the input measured signal, and a signal passing through the third filter section and a signal passing through the second filter section are switched. The cutoff frequency of the first filter unit is set based on the switching unit and the signal through the switching unit, and the timing control of the S / H and A / D conversion unit and the memory is performed. PLL to synchronize with LL synchronization method
Unit, storage control unit, and CPU, the data of not only the fundamental wave (harmonic) component of the input measured signal but also its carrier component can be accurately stored in the memory. It is possible to not only perform waveform analysis of voltage, current effective value, power value, and fundamental wave component based on the data, but also accurately perform waveform analysis of carrier wave component that is asynchronous with the fundamental wave. By continuously displaying the fundamental wave and carrier wave of
For example, when a motor is driven by an inverter type power supply, noise and noise can be analyzed more easily.

Further, according to the power analyzer of the present invention, since it is sufficient to add a programmable filter and an analog switch to the conventional circuit, it does not become expensive like the FFT analyzer and can be made inexpensive. effective.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of a power analyzer device showing an embodiment of the present invention.

FIG. 2 is a schematic frequency spectrum diagram for explaining the operation of the power analyzer device shown in FIG.

FIG. 3 is a schematic display screen diagram illustrating the operation of the power analyzer device shown in FIG.

FIG. 4 is a schematic display screen diagram for explaining the operation of the power analyzer device shown in FIG.

5 is a schematic display screen diagram for explaining the operation of the power analyzer device shown in FIG. 1. FIG.

6 is a schematic display screen diagram for explaining the operation of the power analyzer device shown in FIG. 1. FIG.

FIG. 7 is a schematic display screen diagram illustrating the operation of the power analyzer device shown in FIG.

FIG. 8 is a schematic display screen diagram illustrating an operation of the power analyzer device shown in FIG. 1.

FIG. 9 is a schematic block diagram of a conventional power analyzer device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Input part 2 1st filter part (an anti-aliasing filter) 3 S / H and A / D conversion part 4 Memory (RAM) 5 Storage control part 6 2nd filter part (low-pass filter) 7 Frequency measurement part 8 PLL Section 9 Oscillator 10 First Switching Section (Analog Switch) 12 Bus Line (Address Bus, Data Bus) 14 Indicator 15 Key Section 16 Third Filter Section (Programmable Filter) 17 Second Switching Section (Analog Switch) 18 CPU 19 memory (ROM / RAM)

Claims (1)

[Claims] 1. A first filter means having a variable cutoff frequency for passing at least a predetermined frequency band of an input measured signal (measured voltage, current), and a second filter means for passing a fundamental frequency of the input measured signal. Filter means, a third filter means for passing a fundamental frequency of a carrier component included in the input measured signal, a signal passed through the third filter means and the second filter means Switching means for switching and outputting a signal, A / D conversion means for sampling the signal passed through the first filter means at a predetermined frequency and converting it digitally, and a memory for storing the digitally measured data. Switching the switching means, setting a cutoff frequency of the first filter means based on a signal transmitted through the switching means, the A / D conversion means and the memory And a control unit for synchronizing the timing control of the A / D conversion unit and the timing control of the memory by the fixed synchronization system, and switching the switching unit to the second filter unit side. As a result, the fundamental wave component of the input measured signal is digitally converted and stored in the memory, and the switching means is the third circuit.
By switching to the filter means of (1), the carrier component is digitally converted and stored in the same memory, and it is possible to calculate the power value and the like based on the fetched data and analyze the waveforms of the fundamental component and the carrier component. Power analyzer device characterized by.