JPS6383987U

JPS6383987U -

Info

Publication number: JPS6383987U
Application number: JP17685886U
Authority: JP
Priority date: 1986-11-18
Filing date: 1986-11-18
Publication date: 1988-06-01

Description

[Brief explanation of the drawing]

第１図はこの考案の実施例を示す回路図、第２
図は従来技術を例示する回路図である。なお前記
両図において同一機能の回路構成要素に対しては
同一の表示符号を附している。１……しや断器または接触器、２……整流器、
３……接触器、４……電圧比較器、５……トラン
ジスタ、６……電圧形インバータ、７……交流電
動機、８……トランジスタ制御回路、Ｃ……平滑
用コンデンサ、Ｒ_１……充電電流抑制抵抗、Ｒ_２……制動抵抗、Ｒ_３……限流抵抗、ＶＲ_１，ＶＲ
_２，ＶＲ_３，ＶＲ_４……可変抵抗、ＣＰ_１，ＣＰ
_２……コンパレータ、ＺＤ……定電圧ダイオード
、Ｅｄ……平滑用コンデンサ端子電圧。 Figure 1 is a circuit diagram showing an embodiment of this invention, Figure 2 is a circuit diagram showing an embodiment of this invention.
The figure is a circuit diagram illustrating a conventional technique. In both figures, circuit components having the same function are given the same reference numerals. 1... Line breaker or contactor, 2... Rectifier,
3... Contactor, 4... Voltage comparator, 5... Transistor, 6... Voltage type inverter, 7... AC motor, 8... Transistor control circuit, C... Smoothing capacitor, R ₁ ... Charging Current suppression resistance, _R2 ...braking resistance, R ₃ ... current limiting resistance, VR ₁ , VR
₂ , VR ₃ , VR ₄ ... variable resistance, CP ₁ , CP
₂ ... Comparator, ZD... Constant voltage diode, Ed... Smoothing capacitor terminal voltage.

Claims

[Scope of utility model registration request]

An AC power source switching circuit breaker or contactor, an AC input rectifier, a smoothing capacitor for the output of the rectifier, a resistor for suppressing the charging current of the capacitor, a contactor for shorting the suppressing resistor, and a voltage comparator for exciting the contactor. An inverter device comprising a DC intermediate circuit comprising a braking resistor for suppressing overvoltage of the capacitor terminal voltage and a transistor for energizing the braking resistor, and a voltage source inverter that uses the intermediate circuit output voltage as a power source to drive an AC motor as a load, a voltage dividing resistor connected in parallel with the capacitor and taking out the terminal voltage of the capacitor from its intermediate tap; and a voltage dividing resistor connected in parallel with the braking resistor and taking out the voltage drop value due to the current flowing through the braking resistor from its intermediate tap. a constant voltage circuit consisting of a constant voltage diode and its current limiting resistor whose power source is the capacitor terminal voltage; a voltage dividing resistor,
a comparator for determining the magnitude of a reference setting voltage set by one of the two sets of voltage dividing resistors and a capacitor terminal voltage detected by the voltage dividing resistor; and a reference setting voltage by another one of the two sets of voltage dividing resistors. a comparator that determines the magnitude of the voltage drop across the braking resistor detected by the voltage dividing resistor; and a transistor control circuit that controls conduction of the braking resistor energizing transistor based on the output signal of the capacitor terminal voltage determining comparator. , an AND element is provided which performs a logical AND operation on the output signals of both the comparators and provides a contact opening signal to the AC power supply switch breaker or contactor, and the AND element and both comparators are used to connect the capacitor to the capacitor. detects a state in which the terminal voltage of the braking resistor is lower than its reference setting voltage and the voltage drop value across the braking resistor is greater than the reference setting voltage, and determines this state to be an abnormality in the DC intermediate circuit and disconnects the AC power supply switching circuit. A voltage source inverter protection circuit characterized by opening a contactor or a contactor.