KR20010081702A - Hybrid contactor - Google Patents

Abstract

An object of the present invention is to prevent malfunction due to safety accidents or poor auxiliary contact in the switch structure of the hybrid structure in which the semiconductor switch is connected in parallel with the electronic switch, to prevent the occurrence of arcs when turned on / off, to reduce the size of the switch One hybrid switch is provided.

An object of the present invention, the contact coil opening and closing drive coil 22 for controlling the short circuit, opening of the main contact point 22A of the switchgear to interrupt the supply of the power supply 21 of the load 23; SCR connected to the main contact 22A in the opposite direction to each other and turned on for a predetermined time immediately before and after the section in which the main contact 22A is substantially shorted to supply a load current (SCR1), ( SCR2); A snubber 25 for suppressing a spike voltage generated at both ends of the SCRs SCR2 to a predetermined value or less; In addition to outputting the coil driving voltage (V_coil) to the drive coil 22, to detect the level change of the input driving voltage (V_input) to drive the SCR (SCR1), (SCR2) at the same timing A drive coil voltage controller 27 for outputting a gate drive pulse train Vx; It is achieved by the gate driver 28A which is driven by the gate driving pulse train Vx and supplies the gate drive signals of the SCR1 and SCR2.

Description

Hybrid switchgear {HYBRID CONTACTOR}

The present invention relates to a switch structure design technology of a hybrid structure in which a semiconductor switch is connected in parallel with an electromagnetic contactor. In particular, the present invention prevents a malfunction due to a safety accident or a poor auxiliary contact, and prevents arcing during turn on / off. The present invention relates to a hybrid switch capable of reducing the size of the switch.

Electronic switchgear is the most widely used to electrically connect or disconnect power and load. The switch connects or separates between fixed electrodes that are spatially separated by a moving electrode, which uses the force of an electromagnet when connecting and uses the force of a spring when separating.

However, if the switch is opened while the current is flowing to the electrode, an arc phenomenon occurs at the contact portion due to energy stored in the inductance component of the line, the load, or the power supply side, thereby damaging the contact. In addition, the arc voltage is generated due to the chattering of the electrode even when the contact is shorted. Therefore, in order to withstand such arc generation, the switch contact portion requires a special material and shape, and an arc extinguishing portion is provided near the contact point of the switch to quickly and safely extinguish the generated arc.

In order to overcome the problems of the mechanical electronic switch as described above, SSR (Soiid-State Relay) or SSC (Sii: Soiid-StateContactor) in which all switches are composed of semiconductors has been proposed and used. However, since SSR or SSC generates a lot of heat due to the voltage drop across the semiconductor switch when it is energized, it is used only for special purposes because it has a disadvantage of using a heat sink or a cooling fan. have. Recently, a hybrid switch has been proposed that takes only the advantages of SSC and the advantages of an electronic switch.

1 is a circuit diagram of a hybrid switch according to the prior art, as shown therein, a main contact 12A for controlling the supply of power 11 to the load 13 side; A triac (TR) for preventing arcing when the main contact (12A) is shorted or opened; An auxiliary contact 12B interlocked with the main contact 12A to control driving of the triac TR; Consists of a contact opening and closing drive coil 12 for controlling the opening and closing operation of the main contact 12A and the auxiliary contact 12B installed between the power supply 11 and the load 13, the operation thereof is as follows. .

When the auxiliary contact 12B is shorted while the main contact 12A is open, the gate G of the triac TR remains shorted with the cathode K, so the triac TR is turned off. State is maintained. At this time, a minute current flows through the resistor R between the power source 11 and the load 13.

In this state, when a voltage is applied to the drive coil 12 for contact opening and closing in order to turn on the switch, the movable electrodes of the main contact 12A and the auxiliary contact 12B of the switch start to move simultaneously. At this time, before the main contact 12A is shorted, the auxiliary contact 12B is opened first so that a driving current of about several tens mA flows through the gate G of the triac TR. Accordingly, the triac TR ) Is turned on, whereby the power source 11 is supplied to the load 13 via its triac TR.

When the main contact 12A is shorted after a certain time has elapsed, a slight chatter occurs due to mechanical characteristics, but the gate G of the triac TR is opened at the moment the main contact 12A is opened. Since the current flows again, the arc does not occur at the mechanical contact point. After that, if the mechanical contact is completely shorted, the voltage at both ends of the triac TR almost reaches zero voltage, and thus the minimum voltage (eg, several Volt) necessary for energizing the triac TR is not secured. The triac TR is turned off.

On the other hand, when the driving voltage of the driving coil 12 is cut off to turn off the switch, the movable electrodes of the main contact 12A and the auxiliary contact 12B simultaneously start to move in the opposite directions to the first and then the main contact ( 12A) is opened. As soon as the main contact 12A is opened, a driving current flows again to the gate G of the triac TR so that the triac TR is turned on, and thus the load current through the triac TR. Is supplied. At this time, since the voltage drop across the triac TR is several volts or less, arc generation is suppressed.

If the auxiliary contact 12B is shorted after a certain time has elapsed, the gate G and the cathode K of the triac TR are thereby shorted. Accordingly, the polarity of the load current through the triac TR changes, and current continues to flow in that state, and becomes zero current when the triac TR is turned off.

However, in the conventional hybrid switch as described above, there are some important problems as follows from the viewpoint of leakage current and reliability. First, since a current of several tens of mA flows even when the main contact point of the switch is open, a safety accident may occur when a part of the human body is in contact with the energization unit. Second, since the triac is turned on or off by the opening or closing state of the auxiliary contact regardless of the opening or closing state of the main contact, the triac is turned on due to a poor contact state or vibration of the auxiliary contact, which may cause a safety accident. If the current continues to flow through the bay, a lot of heat is generated in the triac, causing the device to be destroyed or short-circuited.

Accordingly, the first object of the present invention is to turn on / off the semiconductor switch by using the control signal of the driving coil of the electronic switch without using the auxiliary contact of the switch when generating the gate driving signal of the semiconductor switching circuit to ensure reliability. A hybrid switch for determining a turn off time point is provided. A second object of the present invention is to provide a hybrid switch that uses a modular semiconductor switch instead of the arc extinguishing portion of the electronic switch in order to reduce the size of the parts and prevent arc generation.

1 is a circuit diagram of a hybrid switch according to the prior art.

Figure 2 is an exemplary block diagram of a hybrid switch according to the present invention.

3 is a detailed block diagram of the drive coil voltage controller in FIG.

(A)-(i) is a waveform diagram of each part of FIG.

Figure 5 is a block diagram of another embodiment of a hybrid switch according to the present invention.

Figure 6 is a perspective view of another embodiment of a hybrid switch according to the present invention.

Figure 7 is a perspective view of another embodiment of a hybrid switch according to the present invention.

*** Description of the symbols for the main parts of the drawings ***

21: power supply 22: drive coil

22A: main contact 23: load

24A: semiconductor switch 25: snubber

26A: drive coil voltage controller 27: drive coil voltage controller

28A: Gate driver

FIG. 2 is a block diagram illustrating an exemplary embodiment of a hybrid switch for achieving the object of the present invention. As shown in FIG. 2, the power supply 21 of the load 23 is controlled by controlling a short circuit and an opening of the main contact point 22A of the switch. Contact opening and closing the drive coil 22 to control the; SCR (SCR1) and (SCR2) which are connected in parallel to the main contact point (22A) in reverse direction and are turned on for a predetermined time immediately before and after the period in which the main contact point (22A) is substantially short-circuited. )and; A snubber 25 for suppressing spike voltages generated at both ends of the SCRs SCR2 below a predetermined value; In addition to outputting the coil driving voltage (V_coil) to the drive coil 22, to detect the level change of the input driving voltage (V_input) to drive the SCR (SCR1), (SCR2) at the same timing A drive coil voltage controller 27 for outputting a gate drive pulse train Vx; 3 and the gate driver 28A which is driven by the gate driving pulse train Vx and supplies the gate drive signals of the SCR1 and SCR2. A detailed description with reference to FIG. 4 is as follows.

At any point in time When the input driving voltage V_input as shown in FIG. 4A is applied to the driving coil voltage controller 27, it is rectified by the internal rectifier 31 and then supplied to the voltage divider 32. The voltage is divided into predetermined levels, and on the other hand, the voltage is supplied to the constant voltage generator 34 to output the control voltage Vcc and the driving voltage Vdd.

The voltage detector 33 detects a level change of the input driving voltage V_input based on the output voltage of the voltage divider 32 and the output voltage Vcc of the constant voltage generator 34 to be raised above a predetermined level. When the level detection signal V_com is outputted as "high", the level detection signal V_com is outputted as "low" when falling below a predetermined level. Thus, the point of view ( ), The level detection signal V_com of the voltage detector 33 transitions from "low" to "high" as shown in FIG.

As described above, when the level detection signal V_com transitions from "low" to "high", the pulse generator 35A generates a short pulse having a pulse width Tp as shown in FIG. At the same time, the pulse generator 35B generates a pulse V_Pulse having a pulse width of Ta as shown in FIG.

section( ), The main contact point 22A of the switch is not short-circuited yet, but the movable contact part is in a moving state. In general, since it takes a time of about Tb (20 to 50 ms) as in FIG. 4E to short-circuit the main contact point 22A of the switch, the drive coil voltage for opening and closing the contact coil 22 in the drive coil voltage controller 27. The drive signal may be supplied to the gates G1 and G2 of the SCR1 and SCR2 connected in parallel with the main contact 22A after outputting the coil drive voltage V_coil. In this case, Ta = 0 in Fig. 4, and the pulse generator 35B is unnecessary.

However, in order to minimize the calorific value of the SCR1 and SCR2, the pulse generator is delayed after delaying the turn-on operation of the SCR1 and SCR2 for a predetermined time (for example, Ta = 20 ms). At the instant when the output pulse V_Pulse of 35B transitions from "high" to "low", a short pulse having a pulse width Td is generated in the pulse generator 35D as shown in FIG. The output pulse of the pulse generator 35D is then combined with the output signals of the oscillator and the sawtooth generator 36 at the AND gate AD32 through the OR gate OR32, and then the gate drive as shown in FIG. The pulse string Vx is output.

The transistor Qc and the gate driver 28A are driven by the gate driving pulse train Vx output from the AND gate AD32, thereby driving the gate G1 and G2 driving signals from the gate driver 28A. Each of them is turned on to turn SCR (SCR1) and (SCR2) on.

For example, When the main contact point 22A of the switch is short-circuited at), the SRCs (SCR1) and (SCR2) are at the time point ( 4) and the load current through them is supplied as shown in FIG. 4 (h), and when the main contact point 22A is shorted, the voltages of the SCR1 and SCR2 become zero, and they are turned off again. do.

If the main contact point 22A of the switch is Even if a short circuit is not performed and chattering occurs, the view point (g) of FIG. SCR1 by the gate driving pulse train Vx supplied to the gates G1 and G2 of SCR1 and SCR2 connected in parallel with the main contact 22A until reaching ), (SCR2) is repeatedly turned on and off, so no arc phenomenon occurs at the main contact point 22A of the switch.

If the high voltage is supplied to the driving coil 22 after the turn-on operation of the switch is finished through the above process, the driving coil 22 may be damaged or a strong residual magnet may be caused. As in c), the coil driving voltage V_coil having a modulated pulse width is supplied. At this time, the pulse width may be as short as several μsec, and it is necessary to use a frequency of about 20 kHz to reduce audible noise.

To this end, the comparator 38 compares the output pulses of the oscillator and the sawtooth generator 36 with the output pulses of the pulse width controller 37 to generate a pulse width modulated signal S_PWM, and generates the pulse width modulated signal S_PWM. Is supplied to one input terminal of the AND gate AD31 through the OR gate OR31. Accordingly, it is possible to supply the required pulse train through the coil driver 39 during the section in which the detection voltage V_com of the voltage detector 33 is "high" as shown in FIGS. 4B and 4C. .

On the other hand, as shown in FIG. 4A, when the input driving voltage V_input starts to transition to " low " In FIG. 4B, the level detection signal V_com of the voltage detector 33 transitions from "high" to "low".

At this time, as shown in (f) of FIG. 4, the pulse generator 35C generates a short pulse having a pulse width of Te, which is the oscillator and the sawtooth generator at the AND gate AD32 through the oragate OR32. The gate driving pulse train Vx as shown in Fig. 4G is outputted by combining with the output signal of 36).

Accordingly, as described above, the driving signals of the gates G1 and G2 of the SRC1 and SCR2 are generated through the transistor Qc and the gate driver 28A. At this time, the main contact point 22A is not immediately opened, but has a predetermined delay time Tc as shown in FIG. In the SSR (SCR1), (SCR2) is to maintain the off state and plays a role of supplying a load current from the moment the main contact (22A) is opened.

After that, When the gate signals of the gates G1 and G2 of the SCR1 and SCR2 are blocked, the polarity (direction) of the current flowing through the SCR1 and SCR2 is reversed. Keep it on, Off). At this time, the spike voltage generated at both ends of SRC1 and SCR2 by the snubber 25 composed of the resistor Rs, the capacitor Cs and the varistor ZNR1 is suppressed to a predetermined value or less.

On the other hand, Figure 4 (i) shows the energized section of the current finally supplied to the load 23, the time when the SCR (SCR1), (SCR2) is turned on ( ) Is turned off at ) Indicates that it is an energized section. In addition, Figure 4 (h) shows the current section flowing through the SCR (SCR1), (SCR2) when the hybrid switch is turned on and turned off once, the SCR (SCR1), (SCR2) In order to minimize the amount of heat generated at, the lengths of the sections Tf and Tg should be designed to be minimum. For reference, the present invention is not limited to the SCR (SCR1), (SCR2) of the semiconductor switch connected in parallel with the main contact point 22A of the switch as described above, triac, GTO, IGCT The same effect can be obtained by using various types of semiconductor devices such as RCT and IGBT. In addition, in the above description, one main contact point 22A has been described as an example, but the same applies to two-phase single phases and multi-phases having three or more contacts.

On the other hand, Figure 5 shows another embodiment of the present invention. The drive coil voltage controller 27 is basically the same as in FIG. 2, and in FIG. 2, the gate driver 28A is implemented using a pulse transformer, while in FIG. 5, the gate driver 28B is formed using a phototriac PTR. ) Is different.

When the gate driving pulse train Vx is output from the drive coil voltage controller 27, the port triac PTR is turned on. Accordingly, the gates G1 and G2 of the SCR1 and SCR2 are connected through the resistor R3 and the triac, and according to the polarity of the voltages between the SCR1 and the SCR2. A current flows through one gate, thereby turning on the corresponding SR.

The gate driver 28B of this type has the advantage that the drive coil voltage controller 27 can supply very little electric energy because the volume and power consumption are small, whereas the secondary breakdown voltage of the port triac PTR is increased. There are features that require high and features that require measures to prevent malfunction due to noise.

Meanwhile, as shown in FIG. 6, the arc extinguishing unit 61 is removed from the conventional electronic switch, and the module including the SCR1, SCR2, and the gate driver 28A and 28B of FIG. 2 or 5 is removed. Mounting or mounting the module composed of the gate driving units 28A and 28B on the side surfaces 73 of the main contact portions 71 and 72 of FIG. 7 can reduce the size and height of the switch.

As described in detail above, the present invention, by using the control signal of the drive coil voltage controller without determining the on-off time of the semiconductor switch connected in parallel to the main contact by using the control signal of the drive coil voltage, There is no malfunction occurs at all has the effect of ensuring high reliability. In addition, since the arc phenomenon does not occur when the switch is turned on or off, the elastic modulus of the spring connected to the main contact point of the electronic switch can be reduced, thereby ultimately reducing the rated capacity of the electromagnet of the drive coil, and the main contact point in the turn-off state. Since the gap between them can be reduced, the degree of freedom of the electrode material and shape of the main contact point increases, thereby reducing the overall size or cost of the product and maximizing the lifetime. In addition, it is possible to control the arc extinguishing unit located at the upper end of the switch and to attach the semiconductor switch module to the upper side or the side of the contact, thereby reducing the height of the switch.

Claims (8)

A contact opening / closing drive coil 22 for controlling the main contact point 22A to control the power supply of the load; A semiconductor switch unit 24A which is turned on for a predetermined time immediately before and after the short circuit section of the main contact point 22A to supply current to the load; A gate driving pulse train Vx is supplied based on a level change of an input driving voltage V_input to supply a driving voltage V_coil to the driving coil 22 and to drive the semiconductor switch unit 24A at the same timing. A drive coil voltage controller 27 for generating a; And a gate driver (28A) which is driven by the gate driving pulse train (Vx) and supplies a drive signal of the semiconductor switch unit (24A). 2. The hybrid switch according to claim 1, wherein the semiconductor switch section (24A) is composed of SCRs (SCR1) and (SCR2) connected in parallel to the main contact points (22A) in opposite directions. 3. The resistor and capacitor (Rs, Cs) according to claim 1 or 2, wherein the semiconductor switch section (24A) is connected in parallel to the main contact point (22A) in order to suppress the spike voltage generated at both ends of the internal semiconductor switch. , A hybrid switch comprising a snubber (25) composed of a varistor (ZNR1). 2. The driving coil voltage controller (27) according to claim 1, further comprising: a voltage detector (33) for comparing the input driving voltage (V_input) with a reference level and outputting a level detection signal (V_com) of the square wave according thereto; A pulse generator (35A) for outputting a pulse in the form of a short pulse when the level detection signal (V_com) transitions from "low" to "high"; An OR gate OR31 for ORing an output signal of the pulse generator 35A and a series of pulse width modulation signals S_PWM; An AND gate AD31 for and combining the output signal of the OR gate OR31 and the level detection signal V_com; And a coil driver (39) which is switched by an output signal of the AND gate (AD31) to generate the driving voltage (V_coil). The continuous "high" signal according to claim 1, wherein when the drive coil voltage controller 27 generates the gate drive pulse train Vx, the level detection signal V_com transitions from "low" to "high". Hybrid output switch, characterized in that configured to output a pulse train of about 20kHz from the time when the turn-on operation of the switch. 2. The driving coil voltage controller (27) according to claim 1, further comprising: a voltage detector (33) for comparing the input driving voltage (V_input) with a reference level and outputting a level detection signal (V_com) of the square wave according thereto; A pulse generator 35B for generating a pulse V_Pulse having a predetermined pulse width Ta when the level detection signal V_com transitions from "low" to "high"; A pulse generator 35D for outputting a pulse having a predetermined pulse width Td when the pulse V_Pulse transitions to "low"; A pulse generator 35C for generating a short pulse having a predetermined pulse width Te when the level detection signal V_com transitions from "high" to "low"; An oragate (OR32) for ORing the output pulses of the pulse generators (35C) and (35D); And an AND gate (AD32) for generating the gate driving pulse train (Vx) by AND combining the output pulse of the OR gate (OR32) with a predetermined oscillation signal. The gate driving unit (28A) of claim 1, further comprising: a pulse transformer driven by the gate driving pulse train (Vx); And a diode and a capacitor for rectifying and smoothing an output pulse of the pulse transformer to generate a gate driving signal of the semiconductor switch unit 24A. The hybrid switchgear according to claim 1, wherein the gate driver (28A) comprises a phototransistor.