JP2006170677A - Grounding detection circuitry of inverter device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grounding detection circuit which is cheap and space-saving. <P>SOLUTION: The grounding detection circuit of the inverter device comprises a wiring pattern 2 for power supply provided on a printed substrate 4, a pair of parallel wiring patterns provided on the printed substrate 4, and a Hall IC 1 provided near the wiring pattern 2, and detects the magnetic flux generated by the reciprocating current flowing in the parallel wiring pattern. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a ground fault detection circuit that detects a ground fault of an inverter device or the like.

As a ground fault detection circuit of a conventional inverter device, there is one using a zero-phase current detector (see, for example, Patent Document 1).
FIG. 4 is a conventional ground fault detection circuit applied to an inverter device. In FIG. 4, reference numeral 5 denotes an inverter device, which includes 51 rectification units and 52 inverter units. 6 is a motor, and 7 is a zero-phase current detector that detects a ground fault. 8 is a ground fault line indicating a ground fault.
As shown in the block diagram of FIG. 5, the zero-phase current detector 7 includes a hall element 71, a core 75, a winding 76, a stabilized power source 72, and an amplifier 73.
This ground fault detection circuit operates as follows. First, the inverter device 5 converts the electric power rectified by the rectification unit 51 into electric power by the inverter unit 52 and drives the motor 6. If there is no ground fault at this time, the direct currents Ia and Ib from the rectifying unit 51 are equal. Therefore, the Hall element 71 does not detect anything and the output of the amplifier 73 is zero. That is, the zero phase current detector 7 does not operate. On the other hand, when a ground fault occurs, the circuit becomes a ground fault line 8 and the direct currents Ia and Ib are different. Then, the Hall element 71 detects a magnetic field generated in the core 75 and an output appears in the amplifier 73. The output of this zero-phase current detector activates a protection device (not shown).
JP 07-140191 (3rd page, FIG. 1)

However, since the conventional ground fault detection circuit uses a zero-phase current detector, there is a problem that it is expensive and also requires a large space.
The present invention has been made in view of such problems, and an object thereof is to provide an inexpensive and space-saving ground fault detection circuit.

  In order to solve the above problem, the present invention provides a ground fault detection circuit for an inverter device having a power supply wiring pattern provided on a printed circuit board, and a pair of parallel patterns provided on the printed circuit board, It has a Hall IC provided in the vicinity, and detects a magnetic flux generated by a reciprocating current flowing in the parallel pattern.

  According to the first aspect of the present invention, since the Hall IC is provided in the vicinity of the pair of parallel wiring patterns through which the reciprocating current flows, a ground fault can be detected, and an inexpensive and space-saving ground fault detection circuit is provided. it can.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a side sectional view of a ground fault detection circuit showing an embodiment of the present invention. In the figure, 1 is a Hall IC, and 21 and 22 are parallel wiring patterns through which a reciprocating current flows. 31 and 32 are magnetic fluxes generated by the current flowing through the wiring patterns 21 and 22, and 4 is a printed circuit board.
The Hall IC 1 includes a Hall element 11, a stabilized power supply 12, an amplifier 13, and a Schmitt trigger 14, as shown in the block diagram of FIG.
Next, the operation will be described.
When there is no ground fault, the magnitudes of the currents Ia and Ib (FIG. 4) flowing in the wiring patterns 21 and 22 are the same. Since two magnetic fluxes are canceled out, the magnetic flux around the Hall IC 1 is small. If an abnormality occurs and a ground fault current flows through the wiring patterns 21 and 22, the magnitudes of Ia and Ib are different. As a result, the difference between the magnetic fluxes 31 and 32 is increased, so that the magnetic flux around the Hall IC 1 is increased. The Hall element 11 senses this magnetic flux and sends a signal to the amplifier 13 and the Schmitt trigger 14 to generate an output. Since the characteristics of the Hall IC are as shown in FIG. 3, a ground fault can be detected from the output of the Hall IC 1. The output of the Hall IC 1 activates a protective device (not shown) as in the conventional case.
The difference between the present invention and Patent Document 1 is that the zero-phase current detector is composed of parallel wiring patterns and Hall ICs.

Side sectional view of a ground fault detection circuit showing an embodiment of the present invention Block diagram of Hall IC used in ground fault detection circuit of the present invention Characteristics diagram of Hall IC used in the ground fault detection circuit of the present invention Block diagram of an inverter device using a conventional ground fault detection circuit The block diagram which shows the ground fault detection circuit of FIG.

Explanation of symbols

1 Hall IC
11, 71 Hall elements 12, 72 Stabilized power supply 13, 73 Amplifier 14 Schmitt trigger 21, 22 Wiring pattern 31, 32 Magnetic flux 4 Printed circuit board 5 Inverter device 51 Rectifier 52 Inverter 6 Motor 7 Zero-phase current detector 75 Core 76 Winding 8 Ground fault wire

Claims (2)

In the ground fault detection circuit of the inverter device having the wiring pattern for power supply provided on the printed circuit board,
An inverter having a pair of parallel patterns provided on the printed circuit board and a Hall IC provided in the vicinity of the wiring pattern, and detecting a magnetic flux generated by a reciprocating current flowing in the parallel pattern Equipment ground fault detection circuit.   2. The ground fault detection circuit for an inverter device according to claim 1, wherein the Hall IC is composed of a Hall element, a stabilized power source, an amplifier, and a Schmitt trigger circuit.

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