JPS614494A - Inverter controller of electric device - Google Patents

Abstract

PURPOSE:To readily measure a frequency by outputting a pulse signal synchronized with the frequency of an inverter power source separately when waveform data is output from a controller. CONSTITUTION:A controller 2 is constructed to output waveform signals from output ports A1-A6 on the basis of a temperature input signal, this signal is input to a transistor drive circuit 3, which outputs a PWM signal at the base side of power transistors Tr1-Tr6. A DC power source 4a is connected with the emitter and collector sides of power transistors Tr1-Tr6 of an inverter 1. The controller 2 has an output port A7 for outputting a pulse signal synchronized with 1/N of a power source frequency, and a frequency measuring circuit 4 is connected with an output port A7.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an inverter control device for driving an electric motor for molding using an inverter, and particularly to measurement of power supply frequency.

<Prior art> Conventionally, in inverter-controlled refrigerators and air conditioners, a waveform signal output from a PWM (pulse width modulation) control circuit switches a power transistor via a transistor drive circuit to simulate a DC power supply. It was converted to AC power to drive the three-phase AC motor of the compressor. In general, the voltage waveform of a pseudo-10 AC power supply is shown in Figure 2 (a
), and it was not easy to measure the frequency, so the waveform was obtained by 7-lier transform. However, in this case, it was extremely difficult to obtain accurately due to the analytical precision of the 7-lier transform. Furthermore, there were cases in which the design did not go as planned due to variations in the precision of circuit components in the p w lV4 control circuit.

Therefore, the present invention provides an inverter control device for electrical equipment that can easily measure the frequency by separately outputting a pulse signal synchronized with the inverter power supply frequency when outputting waveform data from the control circuit. intended to provide.

<Embodiment> Hereinafter, an actual example of the present invention will be explained based on the drawings. This includes an inverter section 1 that converts a DC power source into a pseudo AC power source, and a converter that converts the power frequency output from the inverter section 1. The control circuit 2 is configured to output a pulse signal synchronized with 1/N (N is an integer) of the power supply frequency. A frequency measurement circuit 4 is provided which measures the power supply frequency by inputting a pulse signal output from the power supply.

FIG. 1 is a circuit diagram of a control device, and the control circuit 2 is configured to output a waveform signal from an output port Al-8 6 based on a temperature input signal such as the temperature inside the refrigerator. )Al
The signals from ~A6 are output to the transistor drive circuit 3 of the inverter section 1, and P W ?14 (pulse width modulation waveform) is output from the drive circuit j (to the base side of the power transistors Tri to Tr6). The power source is connected to the emitter side and collector side of power transistors 1'r1 to Tr6 of the inverter section 1.

The control circuit 2 has a power supply frequency of 17Nl.
(N is an integer) output port A'7 that outputs a pulse signal synchronized with
The frequency α1 constant circuit 4 is composed of a frequency counter.

FIG. 2(a) shows the three-phase power supply terminals U, V,
This shows the waveform between U and V of W, and in accordance with the polarity switching of this waveform, the pulse output from the output capacitor A7 of the control circuit 2 is inverted as shown in Figure 2 (b). . Figure 2(c) shows an example in which a pulse signal is output from the output capo A7 at a frequency that is 12 times the basic frequency, and in this case, the value of the frequency counter of the frequency measuring circuit 4 is reduced to 1/2. If you do this, the fundamental frequency will be measured.

Furthermore, it is known that in the case of a three-phase power source, it is possible to output one cycle of data with 1/6 of a -cycle when creating an inverter waveform. Therefore, as shown in Fig. 2(d), the output capacitor (A7) of the control circuit 2 is outputted to a positive level when the first 1/6th data is output, and outputted to a negative level when the remaining 5/6th data is outputted. Frequency measurement is possible even when In this case, 0N10
The frequency of the FF becomes the fundamental frequency.

#3[N+;l:・”2 Q(b)i::zi−′<t
b゛1)′;l]l”°゛j is shown in the flowchart. First, after initializing the control circuit 2, with the operation switch turned on, the temperature inside the lungs, etc. is manually input to the control circuit 2. Then, it is output from the output port A1-80 to the transistor drive circuit 3, and the power) run lister T
r]-.i' r G is driven and three-phase power is supplied to the motor 5. At the same time, control circuit 2 judges whether the U-■ open waveform data is a positive timing or not, and if it is positive, outputs pulse No. 4.1 at a positive level from output capo-)A7, and if it is negative, it outputs pulse No. 4.1 at a positive level. Outputs a pulse signal at the level. As a result, the frequency measurement circuit 1 can measure the three-phase power supply frequency.

Effect> As is clear from the explanation in -1- below, the present invention includes an inverter section that converts a DC power source into a pseudo 11゛j,'4 current power source,
a control circuit that outputs a waveform signal for converting the power supply frequency output from the inverter section, the control circuit being configured to output a pulse No. 18 synchronized with 1/N of the power supply frequency; According to the present invention, when outputting waveform data from the control circuit, a frequency measurement circuit is provided that measures the power supply frequency by inputting a pulse signal output from the control circuit. By outputting synchronized pulse signals, it is possible to easily measure the frequency, which has an excellent effect of ν.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a control device showing an embodiment of the present invention, and FIG.
Figures (a) to (d) are waveform diagrams showing waveform data of the same three-phase power supply U-V open and pulse output from the output port of the control circuit, and Figure 3 is a control flowchart. 1: Inverter, 2: Control circuit, 3: Transistor drive circuit, 4: Frequency measurement circuit.

Claims (1)

[Claims] The control circuit includes an inverter section that converts a DC power source into a pseudo AC power source, and a control circuit that outputs a waveform signal for converting the power frequency output from the inverter section, and the control circuit converts the power source frequency to 1/N of the power source frequency. An inverter control device for electrical equipment, comprising a frequency measuring circuit configured to output synchronized pulse signals and measuring a power supply frequency by inputting the pulse signals output from the control circuit.