JPH04196U

JPH04196U -

Info

Publication number: JPH04196U
Application number: JP3776790U
Authority: JP
Priority date: 1990-04-09
Filing date: 1990-04-09
Publication date: 1992-01-06

Description

[Brief explanation of the drawing]

第１図はこの考案の一実施例によるインバータ
装置の制御回路の回路構成図、第２図は従来のイ
ンバータ装置の制御回路の回路構成図、第３図は
短絡防止期間Ｔｄの出力電圧に対する影響を説明
するための図、第４図はインバータ装置の逆変換
部の１相分のスイツチング素子の構成図である。図において、１は順変換部、２は平滑コンデン
サ、３は逆変換部、４は誘導電動機、５は基準波
形作成回路、６は三角波作成回路、７は比較回路
、８はＴｄ作成回路、９は駆動回路、１０は電流
検出器、１１は電流極性信号作成回路、１２はＴ
ｄ補正有無決定回路、１３はＴｄ補正回路を示す
。なお、図中、同一符号は同一、または相当部分
を示す。 Fig. 1 is a circuit diagram of a control circuit of an inverter device according to an embodiment of the present invention, Fig. 2 is a circuit diagram of a control circuit of a conventional inverter device, and Fig. 3 is an influence of the short-circuit prevention period Td on the output voltage. FIG. 4 is a diagram for explaining the configuration of switching elements for one phase of the inverse conversion section of the inverter device. In the figure, 1 is a forward conversion section, 2 is a smoothing capacitor, 3 is an inverse conversion section, 4 is an induction motor, 5 is a reference waveform creation circuit, 6 is a triangular wave creation circuit, 7 is a comparison circuit, 8 is a Td creation circuit, 9 is a drive circuit, 10 is a current detector, 11 is a current polarity signal generation circuit, 12 is T
d correction presence/absence determination circuit; 13 indicates a Td correction circuit; In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims

[Scope of utility model registration request]

An inverter device that converts three-phase AC power into variable frequency, variable voltage AC power includes a current detector that detects instantaneous values of three-phase currents output from an inverse conversion section to an induction motor; A current polarity signal generation circuit that creates a current polarity signal indicating the direction for each phase, and indicates the output voltage, output frequency, and forward/reverse of each phase based on the output voltage command, output frequency command, and forward/reverse command. A reference waveform creation circuit that calculates and outputs reference waveform data compares the output frequency command and the Td correction/non-correction switching frequency data, and when the former becomes larger than the latter, the T
Td correction presence determination circuit that outputs a d correction no signal, Td data indicating the upper and lower short circuit prevention period of the inverse conversion switching element, and Td from the carrier frequency command.
In addition to calculating correction data, if the Td correction no signal is input, when the current polarity signal of each phase is positive, Td is added to the reference waveform data.
A Td correction circuit that performs a correction process of adding correction data and subtracting it when it is negative, and does not perform the correction process if the Td correction no signal is input; and a reference waveform data corrected by the Td correction circuit. and a comparison circuit that generates a PWM signal by comparing signals of a predetermined frequency and a predetermined waveform according to a carrier frequency command, and a PWM signal that controls the switching element of the inverse conversion section from the PWM signal for three phases. 1. A control circuit for an inverter device, comprising: a Td creation circuit that adds an upper and lower short circuit prevention period when creating the Td.