JP2000036238A - Switch circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a load switch for power free from chattering and arc discharge of a contact at the time of switching operation, and further ensuring high function and high efficiency as well as low cost. SOLUTION: This switch circuit is formed so that the contacts of a semiconductor AC switch S2 and an electromagnetic switch Ry are connected in parallel and a load power supply E is connected across both ends of the parallel connection circuit Ry and S2, and the serial switch of a load L. Furthermore, a switch drive control power supply Vc is connected to the electromagnetic coil Ry and the input side of a delay circuit 1 in an off-delay state, and the output side of the delay circuit 1 is connected to the gate of the semiconductor AC switch S2. Also, both ends of one contact Ry-1 of the switch Ry are connected in parallel to both ends of the two-way thyrister S2, and the load power supply E is connected across both ends of a serial circuit formed out of the parallel connection circuit of Ry-1 and S2, and the load L, thereby constituting a circuit for closing the contact switch Ry after the completion of the closing operation of the control switch S1, and the control switch S1 is connected to the gate of the twoway thyrister S2. At the same time, the contacts Ry-2 are connected in parallel to both ends of the control switch S1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-efficiency, low-cost, electrically clean power switch.

[0002]

2. Description of the Related Art The main advantages of a semiconductor type non-contact switch (hereinafter simply referred to as a semiconductor switch) are that the switching speed is fast, there is no chattering when the switch is opened and closed, and the life is long. The heat generation of the switch body becomes a serious problem, and its heat dissipation measures are serious. On the other hand, for example, a mechanical contact switch such as an electromagnetic switch (hereinafter simply referred to as an electromagnetic switch) has a main advantage in that the contact resistance of the contacts is small, so that the closed state generates little heat and is strong against heat. The switching speed is slow, the contact has chattering when the switch is opened and closed, and the service life is short due to the spark discharge between the contacts when the switch is opened and closed. The device may malfunction or be damaged.

[0003]

SUMMARY OF THE INVENTION Accordingly, the present invention eliminates the disadvantages of a semiconductor switch and an electromagnetic switch, and provides a high-performance, low-cost power switch that generates little heat, has no chattering and spark discharge when the switch is opened and closed. The purpose is to bring economic effects to various fields.

[0004]

According to a first aspect of the present invention, there is provided a switch circuit comprising: a semiconductor switch and an electromagnetic switch connected in parallel; and the semiconductor switch and the electromagnetic switch are connected when the switch is closed. The switches are driven at the same time, and when the switches are opened, the electromagnetic switches are opened first and the semiconductor switches are opened later. Since the operation of the semiconductor switch is fast when the switch is closed, the switch is closed faster than the electromagnetic switch, and the electromagnetic switch always opens and closes while the semiconductor switch is closed. Therefore, there is no chattering and spark discharge in the electromagnetic switch at the time of opening and closing, and in a steady operation state (when the switch is closed), the contact resistance of the electromagnetic switch is small, so that heat generation is small.

In the switch circuit according to the present invention (the second invention according to claim 2), the bidirectional thyristor and one contact of the electromagnetic switch are connected in parallel, and when the switch is closed, the bidirectional thyristor is controlled by the control switch. First, the electromagnetic switch is driven after the control switch is operated after the closing operation, and the bidirectional thyristor is opened using the other contacts of the electromagnetic switch after the electromagnetic switch is opened when the switch is opened. Drive. Therefore, the same effect as the first invention can be obtained.

[0006]

The switch circuit according to the first invention having the above-described structure is
As shown in the time chart of FIG. 1A, when the switch drive control voltage Vc becomes high level Hi, the semiconductor switch is closed and the electromagnetic switch is closed with a delay of the electromagnetic switch closing operation time t1. Become. When the control voltage Vc becomes low level Lo, the electromagnetic switch is opened, and the semiconductor switch is opened with a delay of (t2) or more than the opening operation time of the electromagnetic switch.

In the switch circuit of the second invention having the above-described structure, as shown in the time chart of FIG. 1A, when the switch drive control voltage Vc becomes high level Hi or the control switch is closed. Then, the bidirectional thyristor switch is closed and the electromagnetic switch is closed with a delay of the closing operation time t1 of the electromagnetic switch. Also, the control voltage V
When c becomes low level Lo or when the control switch is opened, the electromagnetic switch is opened first and the bidirectional thyristor switch is opened near zero load current.

[0008]

Next, embodiments of the present invention will be described in detail with reference to the drawings.

(First Embodiment) The switch circuit of the first embodiment is an embodiment of the first invention, and as shown in FIG. 1 (b), a semiconductor AC switch S composed of a power MOSFET.
2 and the contacts of the electromagnetic switch Ry are connected in parallel, and Ry and S2
And the load power supply E across the series circuit of the load L and the load power supply E
And the switch driving control power supply Vc is connected to the electromagnetic coil R.
The output of the delay circuit 1 is connected to the gate of the semiconductor AC switch S2.

In FIG. 1 (b), when the control voltage Vc goes high, the electromagnetic coil Ry and the semiconductor switch S2
Are driven simultaneously, but since the operation speed of the semiconductor switch is faster than the operation speed of the electromagnetic switch, the semiconductor switch is closed first, and when the control voltage Vc becomes low level, the excitation of the electromagnetic coil Ry is stopped. The semiconductor switch is released first, and the semiconductor switch is released after a delay of t2 due to the off-delay of the delay circuit 1, so that the electromagnetic switch is opened first. Therefore, since the opening and closing operation of the electromagnetic switch is always performed while the semiconductor switch is closed, a transient phenomenon at the time of the opening and closing operation of the electromagnetic switch becomes extremely small. Here, the high level of the control voltage Vc is the magnitude of the voltage required for exciting the electromagnetic coil Ry, and the low level is the magnitude of the voltage required for canceling the excitation of the electromagnetic coil Ry. t2 is proportional to the size of the capacitor C of the delay circuit 1. The same effect can be obtained even if the resistor R is removed. In the figure, the same effect can be obtained by the configuration of FIG. 3B in which the electromagnetic switch Ry is a manual switch having two or more poles.
The capacitor C2 and the resistor R6 in the figure are for preventing chattering of the contact and can be removed. The delay circuit 1 is shown in FIG.
-(C) or an electromagnetic switch R as shown in FIG.
A more optimal off-delay delay circuit can be configured using the normally closed contact y. Various types of AC switches shown in FIGS. 2A to 2F can be employed as the semiconductor AC switch S2. When the load power supply E is DC, a DC switch can be used as the semiconductor switch S2.
As shown in (g), FET, transistor, IGBT,
GTO, thyristor, etc. can be adopted. When the control voltage Vc is alternating current, the delay circuit 1 shown in FIG.
Circuit can be adopted. As another example, an embodiment in which the semiconductor switch S2 is a bidirectional thyristor (triac) is shown in FIG. In this figure, the contact R
The same effect can be obtained even if y-2 is removed. Further, the circuit of FIG. 3C or FIG. 3D can be adopted as the circuit block 2 throughout the present invention.

Second Embodiment A switch circuit according to a second embodiment is an embodiment of the second invention. As shown in FIG. 4A, two or more independent thyristors S2 are provided at both ends of a bidirectional thyristor S2. Contact R of a mechanical contact switch Ry provided with a set contact
To connect a load power source E to both ends of a series circuit of a load L and a parallel connection circuit of Ry-1 and S2 and to drive a contact switch Ry and a bidirectional thyristor S2. The contact switch Ry is closed after the closing operation of the control switch S1 is completed.
1 is connected to the gate of the bidirectional thyristor S2, and both ends of the control switch S1 are connected to the other contact Ry- of the contact switch Ry.
2 in parallel.

In FIG. 4A, the control switch S1
Is closed, the bidirectional thyristor switch S2 is closed first, and the electromagnetic switch is closed after a delay of the closing operation time t1 of the electromagnetic switch Ry. When the control switch S1 is opened, the electromagnetic switch Ry is opened first, and subsequently, the bidirectional thyristor switch S2 is opened near zero load current. When the control switch S1 is an electromagnetic switch, as shown in FIG.
Drives the electromagnetic switch S3. As another embodiment, as shown in FIG. 4C, the same effect can be obtained by removing the control switch S1 and only the switch Ry. In the figure, the capacitor C2 and the resistor R6 are for absorbing surge or preventing chattering, and may not be necessary. As another embodiment, as shown in FIG. 4D, the same effect can be obtained by adding a differentiating circuit including the capacitor C1 and the resistor R4 to the circuit of FIG. FIG. 5 shows another embodiment.
As shown in (a), the same effect can be obtained by the combination of the electromagnetic switch Ry and the phototriac S3. In the figure, the circuit block 2 can be replaced with the circuit of FIG. 3- (c) or FIG. 3- (d). FIG. 5 shows another embodiment.
As shown in FIG. 1B, when the electromagnetic switch Ry and the semiconductor switch S2 are driven by different control signals x1 and x2, the timing adjustment of FIG. 1A can be performed by computer software such as a CPU and a personal computer. Throughout the present invention, when a zero-cross type is adopted as the bidirectional thyristor S2, load control such that the power supply E is ON when the voltage of the power supply E is zero and OFF when the load current is zero is possible. Further, as shown in FIG.
Similar effects can be obtained by performing the processing through an ET or IC circuit. As the mechanical structure of the switch circuit of the present invention, various shapes as shown in FIG. 6 and incorporation into other devices are possible.

[0013]

According to the first and second aspects of the present invention, the semiconductor switch and the mechanical switch are operated in parallel in both cases, thereby eliminating the disadvantages of the two. It is possible to provide a high-performance, low-cost power load on / off switch that generates no heat, generates little surge voltage and generates no pulse current.

[Brief description of the drawings]

FIG. 1- (a) is an operation time chart of the present invention.

FIG. 1- (b) is an electric circuit diagram showing the entire first embodiment of the first invention.

FIG. 1- (c) is an electric circuit diagram showing another embodiment of the delay circuit according to the present invention.

FIG. 2 is an electric circuit diagram of various semiconductor switches according to the present invention.

FIG. 3 is an electric circuit diagram showing another embodiment of the first invention.

FIG. 4 is an electric circuit diagram showing the entire second embodiment of the second invention.

FIG. 5 is an electric circuit diagram showing another embodiment of the present invention.

FIG. 6 is a shape diagram showing an embodiment of the mechanical structure of the present invention.

[Explanation of symbols]

1 is an off-delay delay circuit Ry is a mechanical contact switch, L is an electric load S1 is a contact or non-contact control switch S2 is a semiconductor switch or a non-contact switch S3 is a photo triac, a photo MOSFET, etc. Coupler, contactless relay or contact relay E is AC or DC power supply, Vc is drive power supply for mechanical contact or contactless relay

Claims (2)

[Claims] 1. Both ends of a mechanical contact switch are connected in parallel to both ends of a semiconductor contactless switch to open and close the mechanical contact switch with the semiconductor contactless switch closed. A driving power source is connected to a driving unit such as an electromagnetic coil of the contact switch, and the driving power source is connected to a gate of the semiconductor type non-contact switch through an off-delay delay circuit. Switch circuit. 2. The two-way thyristor is connected in parallel to both ends of one contact of a mechanical contact switch having two or more independent contacts, and drives the contact switch and the bidirectional thyristor. A circuit for closing the contact switch after the closing operation of the control switch is completed,
A switch circuit comprising the control switch connected to the gate of the bidirectional thyristor, and the other contact of the contact switch connected in parallel to both ends of the control switch.