JP2005260721A - Solid state relay - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid state relay in which a plurality of control semiconductor devices (standard components) are connected in series and ON/OFF characteristics of the control semiconductor devices can be aligned and balanced with respect to a high voltage. <P>SOLUTION: There are provided photocouplers 3a-3k connected in series, zero cross circuits 4a-4k connected in series and control switching elements 5a-5k connected in series, the switching elements are simultaneously turned on/off while aligning characteristics of the switching elements connected in series so as to equalize voltage resistance of the switching elements. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a solid-state relay that controls the opening and closing of an AC power supply that drives a load, and in particular, semiconductor elements having a voltage withstand capability lower than the voltage of the AC power supply are connected in series, and the voltage of the AC power supply is controlled by each semiconductor element. The present invention relates to a solid state relay that equally distributes and increases voltage withstand capability.

  A conventional solid state relay (SSR) as shown in FIG. 3 is generally known. In FIG. 3, a solid state relay 50 electrically connects input terminals A1 and A2 for connecting a DC power source VDC, an input circuit 51 for passing a photodiode current to the photodiode of the photocoupler PH, and an input system and a control system. A photocoupler PH that is optically coupled by a photodiode and a phototransistor, a zero-cross circuit 52 that sets the operation of the control thyristor SCRa so that switching is started in the vicinity of the zero potential of the AC power supply VAC, and a control thyristor The full-wave rectifier 53 consisting of diodes D1 to D4 that performs full-wave rectification on the SCRa and the AC power supply VAC and generates the rectified power supply VR, and the positive (positive) of the AC power supply VAC when the control thyristor SCRa is turned on. Half cycle of the power thyristor SCRc and the AC power supply VAC that turn on in the half cycle of The power thyristor SCRb that is turned on, the snubber circuit in which the resistor R and the capacitor C that absorb the induced voltage caused by the inductive load are connected in series, and the surge voltage superimposed on the AC power supply VAC from the output terminals B1 and B2 are suppressed. And surge absorber SA. A load L and an AC power source VAC are connected in series to the output terminals B1 and B2. The resistor R1 and the diode D5 and the resistor R2 and the diode D6 control the gate-cathode voltage (bias voltage) for turning on or off the power thyristors SCRb and SCRc, respectively.

  Application of DC power supply VDC → Input circuit 51 operates → Photocoupler PH operates → Zero cross circuit 52 operates → Control thyristor SCRa is turned on → Rectifier power supply VR of full-wave rectifier 53 is short-circuited → Power thyristors SCRb and SCRc are turned on Operation → Short circuit of AC power supply VAC at output terminals B1 and B2 → Supplying AC power supply VAC to load L.

  On the other hand, when the DC power supply VDC is removed, the input circuit 51 does not operate → the photocoupler PH does not operate → the zero cross circuit 52 does not operate → the control thyristor SCRa is turned off → the rectified power supply VR of the full-wave rectifier 53 is opened → The power thyristors SCRb and SCRc are turned off, the output terminals B1 and B2 are used to open the AC power supply VAC, and the supply of the AC power supply VAC to the load L is stopped. In this way, control of supplying or stopping the AC power supply VAC to the load L by the solid state relay 50 is executed.

  When the AC power supply VAC uses a commercial power supply (50/60 Hz, AC100V), commercially available standard parts can also be used for the control thyristor SCRa and the power thyristors SCRb and SCRc.

  For example, in the case of AC100V, 100V represents an effective value (RMS value), so the peak-to-peak value of the AC power supply VAC is 100 × 2√2 (= 283) V, and full-wave rectification The zero-to-peak (0-to-peak) value of the later rectified power supply VR is 100 × √2 (= 141) V.

  The standard parts of the control thyristor SCRa are called low-power general-purpose parts, and the current ratings are several hundred mA and the voltage ratings are up to 600 V. The standard parts of the power thyristors SCRb and SCRc have sufficiently high current ratings (several tens of A). Order), there are those whose rated voltage exceeds 1200V.

  As a recent trend, there is a demand from customers for a solid state relay to increase the voltage of the AC power supply VAC that drives the load. For example, when a 480V AC power supply is used, the control thyristor SCRa and the power thyristors SCRb and SCRc need to have a voltage rating of 700 V or more.

  Further, as disclosed in “Patent Document 1” (non-contact switch), the conventional solid state relay is both used as auxiliary switching elements for driving power thyristors TH1 and TH2 which are switching elements in the output stage. A directional switch DIAC is used, and a triac TRIAC and a photo triac PT are connected in series to the bidirectional switch DIAC in order to improve the voltage resistance.

As a result, the rectifier circuit for rectifying the AC power supply can be eliminated, the voltage tolerance can be realized, and the circuit can be simplified.
JP 2001-7690 A

  When the voltage of the AC power supply VAC is increased (for example, 480 V), the conventional solid-state relay cannot be used with the standard control thyristor SCRa because the voltage withstand capability (voltage rating) is exceeded.

  If the power thyristor SCRb is used for the control thyristor SCRa, the voltage tolerance (voltage rating) can be satisfied with one standard product, but using the power thyristor SCRb instead of the control thyristor SCRa There is a problem that causes an increase in cost. In addition, the power thyristor SCRb has a low sensitivity with a small current, and there is a problem that it is difficult to use in place of the control thyristor SCRa.

  In order to increase the withstand voltage (voltage rating) of the control thyristor SCRa, it is possible to satisfy the withstand voltage (voltage rating) by connecting two standard control thyristors SCRa in series. If the control thyristor SCRa is turned ON → OFF or OFF → ON does not coincide, a high voltage is applied to the control thyristor SCRa in the OFF state, and the voltage withstand capability (voltage rating) of the control thyristor SCRa is exceeded. Therefore, the control thyristor SCRa may be destroyed.

  FIG. 4 is an explanatory diagram of voltage withstand capability excess in which control thyristors are connected in series. (A) The configuration of the serial connection circuit of the control thyristors in the figure, (b) The anode-cathode voltage characteristics of the control thyristor in the off state, (c) The anode-cathode voltage of the control thyristor in the on state. Show properties.

  (A) In the figure, when the thyristor SRa1 and the thyristor SRa2 are off, V / 2 obtained by dividing the high voltage V by two resistors Ra is applied. From this state, an ON signal SON is applied between the gate and cathode of thyristor SRa1 and thyristor SRa2.

  (C) In the figure, when the thyristor SRa2 is turned on at the time t1, for example, by applying the on signal SON, the anode-cathode voltage VA-C of the thyristor SRa2 becomes an on-voltage due to the on-resistance and becomes almost 0V.

  (B) In the figure, the thyristor SRa1 that is in the OFF state at time t1 has the anode-cathode voltage VA-C changed from V / 2 to V at the moment when the thyristor SRa2 is turned on, and exceeds the rated voltage VH for a predetermined time τ. If it passes, voltage breakdown will occur.

  Similarly, the solid state relay disclosed in “Patent Document 1” (non-contact switch) is also in the off state if the on / off timings of the bidirectional switch DIAC, triac TRIAC, and photo triac PT do not match. If the high voltage of the AC power supply is applied to the semiconductor component in (1), the withstand voltage (voltage rating) of the semiconductor component may be exceeded, and the semiconductor component may be destroyed.

  The present invention has been made to solve such problems. The object of the present invention is to connect a plurality of control semiconductor elements (standard parts) in series, and to align the on / off characteristics of the control semiconductor elements to a high voltage. It is to provide a solid state relay that can be balanced against.

  In order to solve the above-described problems, a solid state relay according to the present invention controls the opening and closing of an AC power source that drives a load, and includes a plurality of semiconductor elements having a voltage resistance lower than the high voltage of the AC power source in series. In addition to the connection, the characteristics of a plurality of semiconductor elements are aligned to balance the voltage resistance against high voltage, and the total voltage resistance of the semiconductor elements connected in series is higher than the high voltage of the AC power supply.

  The solid state relay according to the present invention connects a plurality of semiconductor elements having a voltage resistance lower than the high voltage of the AC power supply in series, and balances the voltage resistance against high voltage by aligning the characteristics of the plurality of semiconductor elements. Since the total withstand voltage of the semiconductor elements connected in series is higher than the high voltage of the AC power supply, stable switching can be performed without using any special semiconductor elements even for the high voltage AC power supply. .

  The semiconductor device according to the present invention includes a photocoupler that separates the power supply of the input circuit and the control circuit and transmits an optical signal, and near zero of the AC signal of the AC power supply based on the control signal supplied from the photocoupler. A switching element of a zero cross circuit for turning on the control switching element and a control switching element for on / off control of the power switching element are provided.

  The semiconductor device according to the present invention has a photocoupler that transmits an optical signal by separating the power supply of the input circuit and the control circuit, and is used for control near zero of the AC signal of the AC power supply based on the control signal supplied from the photocoupler. Since the switching element of the zero cross circuit for turning on the switching element and the control switching element for controlling on / off of the power switching element are provided, a plurality of photocouplers, a plurality of switching elements and a plurality of controls connected in series are provided. By aligning the characteristics of the switching elements for use, on / off of the semiconductor elements connected in series can be performed simultaneously.

  Furthermore, the zero-cross circuit according to the present invention is characterized by balancing the withstand voltage applied to the control switching elements connected in series.

  The zero cross circuit according to the present invention balances the withstand voltage applied to the control switching elements connected in series, so that each control switching element is simultaneously turned on and off and applied to each control switching element. Can be suppressed within the rated voltage.

  The photocoupler, the switching element of the zero cross circuit, and the switching element for control according to the present invention are each configured by a semiconductor array having a pair property.

  Since the photocoupler, the switching element of the zero cross circuit, and the switching element for control according to the present invention are each composed of a paired semiconductor array, the characteristics of the plurality of photocouplers, switching elements, and control switching elements connected in series are aligned. be able to.

  Furthermore, the photocoupler according to the present invention is constituted by a phototransistor coupler.

  In addition, the switching element of the zero-cross circuit according to the present invention is characterized by comprising a transistor.

  Furthermore, the switching element for control according to the present invention is constituted by a thyristor.

  Since the photocoupler according to the present invention is composed of a phototransistor coupler, the switching element of the zero cross circuit is composed of a transistor, and the control switching element is composed of a thyristor, the control system semiconductor element is composed of a standard product. Total cost of parts can be reduced.

  The solid state relay according to the present invention connects a plurality of semiconductor elements having a voltage resistance lower than the high voltage of the AC power supply in series, and balances the voltage resistance against high voltage by aligning the characteristics of the plurality of semiconductor elements. Since the total voltage tolerance of the series-connected semiconductor elements is higher than the high voltage of the AC power supply, stable switching can be performed without using a special semiconductor element for the high-voltage AC power supply. Therefore, it is possible to improve the reliability without increasing the cost.

  The semiconductor device according to the present invention includes a photocoupler that separates the power supply of the input circuit and the control circuit and transmits an optical signal, and near zero of the AC signal of the AC power supply based on the control signal supplied from the photocoupler. Since the switching element of the zero cross circuit that turns on the control switching element and the control switching element that controls on / off of the power switching element are provided, a plurality of photocouplers, a plurality of switching elements, and a plurality By aligning the characteristics of the control switching elements, the semiconductor elements connected in series can be turned on and off at the same time, and the high voltage applied to the solid-state relay is kept below the rated voltage of each semiconductor element. Evenly distributed, it is possible to prevent the breakdown voltage of the semiconductor element from being exceeded by applying a high voltage.

  Furthermore, since the zero cross circuit according to the present invention balances the voltage tolerance applied to the control switching elements connected in series, each control switching element is simultaneously turned on / off, and each control switching element is controlled. Can be suppressed within the rated voltage, and the control switching element can be covered with a commercially available standard product.

  In addition, since the photocoupler, the switching element of the zero-cross circuit, and the switching element for control according to the present invention are each composed of a paired semiconductor array, the characteristics of the plurality of photocouplers, switching elements, and control switching elements that are connected in series respectively. It can be freed from man-hours and cost increase required for selecting individual parts.

  Furthermore, since the photocoupler according to the present invention is composed of a phototransistor coupler, the switching element of the zero cross circuit is composed of a transistor, and the control switching element is composed of a thyristor, the control semiconductor element is a standard product. The total component cost can be reduced by configuring, and the cost of the solid state relay for high voltage can be reduced.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a configuration diagram of an embodiment of a solid state relay according to the present invention. As shown in FIG. 3, the solid state relay 1 has a DC power supply VDC connected between the input terminals A1 and A2, and a load L and a high voltage AC power supply VAc connected between the output terminals B1 and B2. Then, the DC power supply VDC is applied between the input terminals A1 and A2 (the DC power supply VDC is turned on) so that the output terminals B1 and B2 are turned on and the load L is driven by the AC power supply VAC (the AC power supply VAC is closed). In addition, the DC power supply VDC is removed from between the input terminals A1 and A2 (the DC power supply VDC is turned off), so that the output terminals B1 and B2 are turned off and the load L drive by the AC power supply VAC is stopped (alternating current). Power supply VAC is released).

  In FIG. 1, a solid-state relay 1 includes diodes D1 to D4 that perform full-wave rectification on an input circuit 2, a photocoupler 3, a zero cross circuit 4, a control switching element 5, and an AC power supply VAC to generate a rectified power supply VR. The power thyristor SCRc (resistor R2, diode D6 is on / off bias) that is turned on in the positive (plus) half cycle of the AC power supply VAC when the full-wave rectifier 6 and the control switching element 5 are turned on. For power), power thyristor SCRb (resistor R1, diode D5 is for on / off bias voltage) that turns on in the negative (minus) half cycle of AC power supply VAC, and absorbs induced voltage caused by inductive load A snubber circuit in which resistor R and capacitor C are connected in series, suppresses the surge voltage superimposed on AC power supply VAC from output terminals B1 and B2. Comprising a surge absorber SA to. The full-wave rectifier 6, the power thyristor SCRb, the power thyristor SCRc, the snubber circuit, and the surge absorber SA have the same configuration as that shown in FIG.

  The input circuit 2 is composed of input circuits 2a to 2k. When a DC power supply VDC is applied between the input terminals A1 and A2 (DC power supply VDC is turned on), a direct current is applied to the photocoupler 3 (photocouplers 3a to 3k). Then, the photocoupler 3 is driven. The input circuit 2 is composed of the input circuits 2a to 2k. However, the input circuit 2 may be a single circuit as long as the same DC current can be supplied to the photocoupler 3 (photocouplers 3a to 3k).

  The photocoupler 3 has photocouplers 3a to 3k connected in series, operates with a DC current supplied from the input circuit 2 (input circuits 2 to 2k), and is connected to the DC power supply VDC side (input circuits 2 to 2k) and the AC power supply VAC. (To be precise, the control signal (optical signal) is transmitted to the rectifying power supply VR side in a state where the rectifying power supply VR side (the control circuit of the zero cross circuit 4 and the control switching element 5) is electrically insulated, and the zero cross circuit 4 (zero cross circuits 4a to 4k) is controlled.

  The photocouplers 3a to 3k are formed by connecting in series a plurality of semiconductor elements (optical coupling elements) having a voltage resistance (rated voltage) lower than the high voltage of the AC power supply VAC, such as a phototransistor coupler, a photodiode coupler, and a photothyristor coupler. Constitute.

  The zero-cross circuit 4 connects the zero-cross circuits 4a to 4k in series, and in the vicinity of 0V of an AC signal (for example, a sine wave) of the AC power supply VAC based on a control signal supplied from the photocoupler 3 (photocouplers 3a to 3k). A drive signal is supplied to the control switching element 5, and the control switching element 5 (control switching elements 5a to 5k) is controlled to be in an ON state.

  The zero-cross circuit 4 (zero-cross circuits 4a to 4k) simultaneously supplies a drive signal or a drive stop signal to the control switching elements 5a to 5k connected in series, and simultaneously turns on / off the control switching elements 5a to 5k. By driving, the high voltage of the rectified power supply VR applied to the control switching elements 5a to 5k is evenly divided so that the voltage tolerance of each control switching element 5a to 5k can be balanced.

  The zero-cross circuit 4 (zero-cross circuits 4a to 4k) is configured by connecting a plurality of semiconductor elements (switching elements) having a voltage resistance (rated voltage) lower than the high voltage of the AC power supply VAC such as transistors and MOSFETs in series.

  Thus, the zero-cross circuits 4a to 4k according to the present invention balance the withstand voltage (rectified power supply VR) applied to the control switching elements 5a to 5k connected in series. 5a to 5k can be simultaneously turned on / off, the voltage applied to each control switching element 5a to 5k can be suppressed within the rated voltage, and the control switching element can be covered with a commercially available standard product.

  The control switching element 5 includes the control switching elements 5a to 5k connected in series, and the control switching elements 5a to 5k are simultaneously turned on based on the drive signal supplied from the zero cross circuit 4 (zero cross circuits 4a to 4k). By short-circuiting the rectified power supply VR, the power thyristors SCRb and SCRc (power switching elements) are turned on.

  Further, the control switching element 5 is simultaneously turned off based on the drive stop signal supplied from the zero-cross circuit 4 (zero-cross circuits 4a to 4k), thereby opening the rectified power supply VR. The power thyristors SCRb and SCRc (power switching elements) are turned off.

  Since the control switching elements 5a to 5k are turned on or off at the same time, the voltage applied to each switching element becomes equal to 1 / k (VR / k) of the rectified power supply VR when turned off.

  The control switching element 5 (control switching elements 5a to 5k) is a semiconductor element (switching element) having a voltage tolerance (rated voltage) lower than the high voltage of the AC power supply VAC such as a thyristor, transistor, MOSFET, etc. for low power. A plurality are connected in series.

  The photocouplers 3a to 3k, the switching elements of the zero-cross circuit 4 and the control switching elements 5a to 5k are each composed of a paired semiconductor array, and the photocouplers 3a to 3k, the switching elements of the zero-cross circuit 4 and the switching elements for control The characteristics of 5a to 5k can be made uniform.

  FIG. 2 is a semiconductor array configuration diagram of an embodiment of a semiconductor device according to the present invention. (A) is a phototransistor coupler array constituting the photocoupler 3, (b) is a transistor array constituting a semiconductor element of the zero-cross circuit 4, and (c) is a thyristor array constituting a control switching element 5. . Each semiconductor array represents a set of two semiconductor arrays.

  In FIG. 2, since the phototransistor coupler array, the transistor array, and the thyristor array are each configured on the same semiconductor substrate (wafer), each element (phototransistor array, phototransistor array, and thyristor array) has a pair property. In addition, since the characteristics can be made uniform, the on / off characteristics (timing) between phototransistors, transistors, and thyristors can be completely matched.

  As described above, the photocouplers 3a to 3k, the switching elements of the zero-cross circuits 4a to 4k, and the control switching elements 5a to 5k according to the present invention are configured by paired semiconductor arrays, respectively. The characteristics of the coupler, the switching element, and the control switching element can be made uniform, and it can be freed from man-hours and cost increase required for selecting individual parts.

  The photocoupler 3, the switching element of the zero-cross circuit 4, and the control switching element 5 are each composed of a photocoupler transistor, a transistor, and a thyristor. By comprising a photocoupler transistor, a transistor, and Siris, commercially available standard standard parts can be used.

  As described above, the photocoupler 3 according to the present invention is constituted by a phototransistor coupler, the switching element of the zero cross circuit 4 is constituted by a transistor, and the control switching element 5 is constituted by a thyristor. The element can be configured as a standard product, reducing the total cost of parts, and reducing the cost of high-voltage solid-state relays.

  The semiconductor element according to the present invention is supplied from the photocoupler 3 and the photocoupler 3 that transmit the optical signal by separating the power supply of the input circuit 2 and the control circuit (the zero-cross circuit 4 and the control switching element 5). Control for controlling on / off of the switching element of the zero cross circuit 4 for turning on the control switching element 5 near the zero of the AC signal of the AC power source VAC and the power switching elements (power thyristors SCRb, SCRc) based on the control signal. Since the switching element 5 is provided, the characteristics of a plurality of photocouplers (photocouplers 3a to 3k), a plurality of switching elements, and a plurality of control switching elements (control switching elements 5a to 5k) connected in series are aligned. Simultaneously turn on / off semiconductor devices connected in series Rukoto can, can the high voltage applied to the solid-state relay evenly distributed below the rated voltage of the semiconductor elements, to prevent the breakdown voltage over the semiconductor element by a high voltage application.

  As described above, the solid-state relay 1 according to the present invention connects a plurality of semiconductor elements having a voltage resistance lower than the high voltage of the AC power supply VAC in series, and has a high characteristic by aligning the characteristics of the plurality of semiconductor elements. Balanced voltage withstand voltage against voltage, increasing the total voltage withstand capability of series-connected semiconductor elements higher than the high voltage of AC power supplies, so stable operation without using special semiconductor elements for high voltage AC power supplies Switching can be executed, and the reliability can be improved without increasing the cost.

  The solid state relay according to the present invention has a plurality of control semiconductor elements (standard parts) connected in series, and the ON / OFF characteristics of the control semiconductor elements can be aligned and balanced against a high voltage. It can be applied to any solid state relay that drives and controls voltage AC loads.

Configuration diagram of an embodiment of a solid state relay according to the present invention 1 is a block diagram showing a semiconductor array according to an embodiment of the present invention. Configuration diagram of a conventional solid state relay Explanatory diagram of overvoltage tolerance with series connection of control thyristors

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solid state relay 2,2a-2k Input circuit 3 Photocoupler 3a-3k Phototransistor coupler 4 Zero cross circuit 4a-4k Drive transistor 5 Control switching element 5a-5k Control thyristor 6 Full wave rectifier A1, A2 Input terminal B1 , B2 Output terminal D1-D6 Diode R, R1, R2 Resistor SCRb, SCRc Power thyristor C Capacitor SA Surge absorber VDC DC power supply VAC AC power supply VR Rectification power supply

Claims (7)

A solid state relay that controls the opening and closing of the AC power supply that drives the load,
A plurality of semiconductor elements having a voltage resistance lower than the high voltage of the AC power supply are connected in series, and the characteristics of the plurality of semiconductor elements are aligned to balance the voltage resistance against high voltage, and the semiconductor elements connected in series A solid state relay characterized in that the total voltage tolerance is higher than the high voltage of the AC power supply. The semiconductor element includes a photocoupler that transmits an optical signal by separating a power supply for an input circuit and a control circuit, and a switching for control near zero of the AC signal of the AC power supply based on a control signal supplied from the photocoupler. 2. The solid state relay according to claim 1, further comprising: a zero-cross circuit switching element for turning on the element; and the control switching element for controlling on / off of the power switching element. The solid state relay according to claim 2, wherein the zero-cross circuit balances a withstand voltage applied to the control switching elements connected in series. 3. The solid state relay according to claim 2, wherein the photocoupler, the switching element of the zero-cross circuit, and the switching element for control are each configured by a semiconductor array having a pair property. 5. The solid state relay according to claim 4, wherein the photocoupler is a phototransistor coupler. 5. The solid state relay according to claim 4, wherein the switching element of the zero-cross circuit is formed of a transistor. 5. The solid state relay according to claim 4, wherein the control switching element comprises a thyristor.

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