CN101355314B

CN101355314B - Circuit for detecting commutation failure of back-to-back silicon-control rectifying circuit and control method thereof

Info

Publication number: CN101355314B
Application number: CN2007101298643A
Authority: CN
Inventors: 狄拉斯·辛·凯纳
Original assignee: TAIDA INTERNATIONAL HOLDING CO Ltd
Current assignee: TEDA electronic Limited by Share Ltd
Priority date: 2007-07-27
Filing date: 2007-07-27
Publication date: 2011-05-18
Anticipated expiration: 2027-07-27
Also published as: CN101355314A

Abstract

The present invention discloses a commutation failure detection circuit and a control method for a back-to-back silicon control rectifier circuit. The circuit comprises a first detection signal generator which detects a commutation at a negative half cycle of an alternating current input voltage and comprises a first non-conducting signal amplifier circuit. When the back-to-back silicon control rectifier circuit is not conducted at the negative half cycle of the alternating current input voltage, the first detection signal generator generates a first non-conducting signal. The circuit also comprises a second detection signal generator which detects the commutation at the positive half cycle of an alternating current input voltage and comprises a second non-conducting signal amplifier circuit. When the back-to-back silicon control rectifier circuit is not conducted at the positive half cycle of the alternating current input voltage, the second detection signal generator generates a second non-conducting signal.

Description

The circuit for detecting commutation failure of back-to-back silicon-control rectifying circuit and control method thereof

Technical field

The invention discloses a kind of circuit for detecting commutation failure (commutation failure detectioncircuit) and control method thereof that is used for the silicon-control rectifying circuit (back-to-backconnected SCR circuit) of a back-to-back connection, refer to a kind of circuit for detecting commutation failure that is used for a back-to-back silicon-control rectifying circuit and control method thereof especially with preferable relatively efficient.

Background technology

The thyristor that uses back-to-back connection with as a static switch, is very common in today between an AC power and a load.For example, please referring to Fig. 1, the circuit diagram that it shows a traditional voltage regulating transformer (tap changing transformer) includes six pairs of back-to-back thyristors (SR1 to SR6).Wherein, each right back-to-back thyristor has one first end (k1 (1) is to k1 (6)) and one second end (k2 (1) is to k2 (6)), and each thyristor has a gate (G1 (1) to G1 (6) and G2 (1) to G2 (6)), be used for linear voltage stabilization (have input voltage 240-520 volt, and output voltage 220 being added and subtracted 10% volt).One use at this of thyristor, need a circuit for detecting commutation failure, avoiding a fault, and cause the badly damaged of transformer because of thyristor.

Please referring to Fig. 2, its demonstration is used for the calcspar of the circuit for detecting commutation failure of traditional use bridge circuit of a back-to-back silicon controlled rectifier circuit and photoelectrical coupler.Show a back-to-back silicon-control rectifying circuit and this circuit for detecting commutation failure among the figure, it comprises a resistor group (resistor bank), be coupled in this back-to-back silicon-control rectifying circuit, one full-bridge circuit, be coupled in this resistor group and this back-to-back silicon-control rectifying circuit, and a photoisolator, have a photoelectrical coupler (not shown), be coupled in this full-bridge circuit, receive a direct current supply voltage and produce an output.

Suppose, one thyristor of this back-to-back silicon controlled rectifier circuit is to the first thyristor (not shown) of (SCR pair), when an AC-input voltage (not shown) of this back-to-back silicon controlled rectifier circuit was a positive half cycle, (some firing angle) was triggered in some firing angle.It is right that one forward voltage is presented in this thyristor, up to this thyristor wherein arbitrary thyristor begun conducting.This forward voltage sees through this resistor group and puts on this full-bridge rectifier, and the purpose of this resistor group is to limit the electric current that flows into this full-bridge circuit.Through the photodiode (not shown) of voltage turn-on in each photoelectrical coupler of rectification, the signal that this photodiode sent then is transferred into this output.

When the right wherein arbitrary thyristor of this thyristor began conducting, then the cross-pressure on this photodiode was zero.Therefore, the output of this photoelectrical coupler there is no signal.And at a negative half period of this AC-input voltage, its operation principles is also similar.

The advantage of the circuit for detecting commutation failure of aforesaid traditional use bridge circuit and photoelectrical coupler is: the number of its part is relatively low.And the shortcoming of the circuit for detecting commutation failure of aforesaid traditional use bridge circuit and photoelectrical coupler is: when AC-input voltage is zero, total applied voltage of crossing over its resistor group descends, and this makes a forward current that can start this full-bridge circuit that comprises four diodes rise slowly.Therefore, in the detecting of the commutation failure of thyristor, always there are some to postpone to produce.

Please referring to Fig. 3, it shows that one is used for the calcspar of circuit for detecting commutation failure of traditional use photoelectrical coupler of a back-to-back silicon controlled rectifier circuit.Show a back-to-back silicon-control rectifying circuit and this circuit for detecting commutation failure among the figure, it comprises a resistor group, be coupled in this back-to-back silicon-control rectifying circuit, and two photoisolators, each this photoisolator has a photoelectrical coupler (not shown) and produces an output, one photoisolator is coupled in this resistor group, and another photoisolator is coupled in this back-to-back silicon-control rectifying circuit and receive a direct current supply voltage.

Suppose that the first thyristor (not shown) that a thyristor of this back-to-back silicon controlled rectifier circuit is right when an AC-input voltage (not shown) of this back-to-back silicon controlled rectifier circuit is a positive half cycle, also is triggered in some firing angle; It is right that then a forward voltage is presented in this thyristor, up to this thyristor arbitrary thyristor wherein begun conducting.The resistor group that this is electrically connected in series is presented in one great voltage drop, and the purpose of this resistor group is to limit the electric current that flows into this photoisolator.Wherein a photoisolator can be switched on it by reverse connection when a negative half period of this AC-input voltage.The one input voltage startup of each this photoelectrical coupler is present in a photodiode (not shown) of each photoelectrical coupler, and transmits the output of a signal to this photoelectrical coupler.

When the right wherein arbitrary thyristor of this thyristor began conducting, then the cross-pressure on this photodiode was zero.Therefore, the output at this photoelectrical coupler there is no signal.When a negative half period of this AC-input voltage, its operation principles also roughly the same.

The advantage of the circuit for detecting commutation failure of aforesaid traditional use photoelectrical coupler is: the number of its part is also relatively low.The shortcoming of the circuit for detecting commutation failure of aforesaid traditional use photoelectrical coupler then is: when AC-input voltage was zero, total applied voltage of crossing over its resistor group descended, and therefore, this forward current that can start this photodiode rises slowly.Therefore, in the detecting of the commutation failure of thyristor, also always have some and postpone to produce.

In sum, the inventor can propose the circuit for detecting commutation failure and the control method thereof of back-to-back silicon-control rectifying circuit of the present invention eventually in view of the disappearance of prior art.

Summary of the invention

Main purpose of the present invention is to provide the circuit for detecting commutation failure that is used for back-to-back silicon-control rectifying circuit and the control method thereof of the preferable relatively efficient of a kind of tool, so that at the delay minimization of the detecting commutation failure that back-to-back silicon-control rectifying circuit presented.

Another main purpose of this case is to provide a kind of circuit for detecting commutation failure that is used for a back-to-back silicon-control rectifying circuit, comprise one first detection signal generator, be coupled in this back-to-back silicon-control rectifying circuit, in order in a negative half period of AC-input voltage time detecting one commutation, comprise one first not conducting signal amplifier circuit, not conducting when this back-to-back silicon-control rectifying circuit this negative half period in this AC-input voltage, then produce one first not conducting signal, one first not conducting signal driver, receive and shift this first not conducting signal, and one first not conducting signal isolator, receive this first not conducting signal through shifting, when this first not conducting signal does not exist, in order to produce one first commutation detection signal of tool one first state, and one second detection signal generator, be coupled in this back-to-back silicon-control rectifying circuit, in order to detect this commutation when the positive half cycle of this AC-input voltage, comprise one second not conducting signal amplifier circuit, not conducting when the positive half cycle of this back-to-back silicon-control rectifying circuit in this AC-input voltage, then produce one second not conducting signal, one second not conducting signal driver, receive and shift this second not conducting signal, and one second not conducting signal isolator, receive this second not conducting signal through shifting, when this second not conducting signal does not exist, in order to produce one second commutation detection signal of this first state of tool.

According to above-mentioned conception, this circuit for detecting more comprises an output node, be coupled in this first and this second not conducting signal isolator, in order to export this first or this second the commutation detection signal, wherein when this first not conducting signal exists, this first commutation detection signal is in one second state, and when this second not conducting signal existed, this second commutation detection signal was in this second state.

According to above-mentioned conception, this first with this second state be respectively a logic high and a logic low state, each this first and this second not conducting signal isolator comprise a photoelectrical coupler, tool two inputs, one output and an earth terminal, wherein this two input be respectively applied for receive a direct current supply voltage and receive with transmit this through shifting first or should be through the second not conducting signal of transfer, this output is in order to export this first or second not conducting signal that should be through transmitting and shifting through transmitting and shifting, and one first resistance, tool one first end and one second end, wherein this first end is coupled in this output, in order to receive this first or second not conducting signal that should be through transmitting and shifting through transmitting and shifting, and be coupled in this output node, in order to produce this first or this second the commutation detection signal, and this second end is respectively applied for and receives a supply voltage, to form a conductive path by this earth terminal, with this logic high state of output device this first or this second commutation detection signal, with form this logic low state of tool this first or this second commutation detection signal.

According to above-mentioned conception, this back-to-back silicon-control rectifying circuit comprises one first and one second thyristor, has a negative electrode separately, this first not conducting signal amplifier which couple is in this negative electrode of this first thyristor, this second not conducting signal amplifier which couple is in this negative electrode of this second thyristor, and each this first comprise a signal bias resistance with this second not conducting signal amplifier circuit, tool one first end, be coupled in a direct current supply voltage, in order to form a not conducting signal bias, and one second end, one detecting current limiting resistance, tool one first end, be coupled in this second end of this signal bias resistance, in order to limit a detecting current of flowing through this detecting current limiting resistance, and one second end, one reverse obstruct diode, tool one anode, be coupled in this second end of this detecting current limiting resistance, and one negative electrode be coupled in this first or the described negative electrode of this second thyristor, in order to prevent a revers voltage, an and signal amplifier, amplify this first or this second not conducting signal, comprise a first order, comprise a first transistor transistor, tool one first end, one second end and a control end, wherein this first end is coupled in this anode of this reverse obstruct diode, and one first resistance, tool one first end and one second end, wherein this first end is coupled in this control end of this first transistor, and this second end be coupled in this first or the described negative electrode of this second thyristor, an and second level, comprise a transistor seconds, tool one first end, one second end and a control end, wherein this first end is coupled in this second end and a ground connection of this first resistance, and this second end is coupled in this first end of this detecting current limiting resistance, and one second resistance, tool one first end and one second end, wherein this first end is coupled in this control end of this transistor seconds, and this second end is coupled in this second end of this first transistor.

According to above-mentioned conception, each this first comprise a Zener diode with this second not conducting signal driver, tool one anode and a negative electrode, wherein this negative electrode is coupled in this first end of this detecting current limiting resistance, one the 3rd resistance, tool one first end and one second end, wherein this first end is coupled in this anode of this Zener diode, one the 3rd transistor, tool one first end, one second end and a control end, wherein this first end is coupled in this ground connection, and this control end is coupled in this second end of the 3rd resistance, one the 4th resistance, tool one first end and one second end, wherein this first termination is received this supply voltage, and this second end is coupled in the 3rd transistorized this second end, one the 5th resistance, tool one first end and one second end, wherein this first end is coupled in this second end of the 4th resistance, one the 4th transistor, tool one first end, one second end and a control end, wherein this first end is coupled in this ground connection, and this control end is coupled in this second end of the 5th resistance, and one the 6th resistance, tool one first end and one second end, wherein this first end is coupled in the 4th transistorized this second end, and this second end is exported this first or this second not conducting signal through shifting through shifting.

According to above-mentioned conception, each this first comprise one the 3rd resistance with this second not conducting signal driver, tool one first end and one second end, wherein this first end is coupled in this first end of this detecting current limiting resistance, one the 3rd transistor, tool one first end, one second end and a control end, wherein this first end is coupled in this ground connection, and this control end is coupled in this second end of the 3rd resistance, one the 4th resistance, tool one first end and one second end, wherein this first termination is received this supply voltage, and this second end is coupled in the 3rd transistorized this second end, one the 5th resistance, tool one first end and one second end, wherein this first end is coupled in this second end of the 4th resistance, one the 4th transistor, tool one first end, one second end and a control end, wherein this first end is coupled in this ground connection, and this control end is coupled in this second end of the 5th resistance, and one the 6th resistance, tool one first end and one second end, wherein this first end is coupled in the 4th transistorized this second end, and this second end is exported this first or this second not conducting signal through shifting through shifting.

According to above-mentioned conception, this back-to-back silicon-control rectifying circuit comprises one first and one second thyristor, has a negative electrode separately, this first not conducting signal amplifier which couple is in this negative electrode of this first thyristor, this second not conducting signal amplifier which couple is in this negative electrode of this second thyristor, and each this first comprise a signal bias resistance with this second not conducting signal amplifier circuit, tool one first end, be coupled in a direct current supply voltage, in order to form a not conducting signal bias, and one second end, one detecting current limiting resistance, tool one first end, be coupled in this second end of this signal bias resistance, in order to limit a detecting current of flowing through this detecting current limiting resistance, and one second end, one reverse obstruct diode, tool one anode, be coupled in this second end of this detecting current limiting resistance, and one negative electrode be coupled in this first or the described negative electrode of this second thyristor, in order to prevent a revers voltage, an and signal amplifier, amplify this first or this second not conducting signal, and comprise that one amplifies diode, tool one anode and a negative electrode, wherein this anode be coupled in a ground connection and be coupled in this first or the described negative electrode of this second thyristor, and this negative electrode is coupled in this first end of this detecting current limiting resistance.

According to above-mentioned conception, each this first comprise a Zener diode with this second not conducting signal driver, tool one anode and a negative electrode, wherein this negative electrode is coupled in this first end of this detecting current limiting resistance, one first resistance, tool one first end and one second end, wherein this first end is coupled in this anode of this Zener diode, one the first transistor, tool one first end, one second end and a control end, wherein this first end is coupled in this ground connection, and this control end is coupled in this second end of this first resistance, one second resistance, tool one first end and one second end, wherein this first termination is received this supply voltage, and this second end is coupled in this second end of this first transistor, one the 3rd resistance, tool one first end and one second end, wherein this first end is coupled in this second end of this second resistance, one transistor seconds, tool one first end, one second end and a control end, wherein this first end is coupled in this ground connection, and this control end is coupled in this second end of the 3rd resistance, and one the 4th resistance, tool one first end and one second end, wherein this first end is coupled in this second end of this transistor seconds, and this second end is exported this first or this second not conducting signal through shifting through shifting.

According to above-mentioned conception, each this first comprise one first resistance with this second not conducting signal driver, tool one first end and one second end, wherein this first end is coupled in this first end of this detecting current limiting resistance, one the first transistor, tool one first end, one second end and a control end, wherein this first end is coupled in this ground connection, and this control end is coupled in this second end of this first resistance, one second resistance, tool one first end and one second end, wherein this first termination is received this supply voltage, and this second end is coupled in this second end of this first transistor, one the 3rd resistance, tool one first end and one second end, wherein this first end is coupled in this second end of this second resistance, one transistor seconds, tool one first end, one second end and a control end, wherein this first end is coupled in this ground connection, and this control end is coupled in this second end of the 3rd resistance, and one the 4th resistance, tool one first end and one second end, wherein this first end is coupled in this second end of this transistor seconds, and this second end is exported this first or this second not conducting signal through shifting through shifting.

Another main purpose of the present invention is to provide a kind of circuit for detecting commutation failure that is used for a back-to-back silicon-control rectifying circuit, comprise one first detection signal generator, be coupled in this back-to-back silicon-control rectifying circuit, in order in a negative half period of AC-input voltage time detecting one commutation, comprise, one first not conducting signal amplifier circuit, not conducting when this back-to-back silicon-control rectifying circuit this negative half period in this AC-input voltage, then produce one first not conducting signal, and comprise one first not conducting signal amplifier, it amplifies this first not conducting signal, and one second detection signal generator, be coupled in this back-to-back silicon-control rectifying circuit,, comprise one second not conducting signal amplifier circuit in order to detecting one commutation when the positive half cycle of an AC-input voltage, not conducting when this back-to-back silicon-control rectifying circuit this positive half cycle in this AC-input voltage, then produce one second not conducting signal, and comprise one second not conducting signal amplifier, it amplifies this second not conducting signal.

According to above-mentioned conception, this circuit for detecting more comprises one first photoelectrical coupler drive circuit, its reception, shift and transmit this first not conducting signal, when this first not conducting signal does not exist, in order to produce the first commutation detection signal of a tool one first state, one second photoelectrical coupler drive circuit, its reception, shift and transmit this second not conducting signal, when this second not conducting signal does not exist, in order to produce the second commutation detection signal of this first state of a tool, and an output node, be coupled in this first and this second photoelectrical coupler drive circuit, in order to export this first or this second commutation detection signal, wherein when this first not conducting signal exists, this first commutation detection signal is in one second state, and when this second not conducting signal existed, this second commutation detection signal was in this second state.

According to above-mentioned conception, this first with this second state be respectively a logic high and a logic low state, each this first and this second not conducting signal amplifier circuit comprise the detecting current limiting resistance and a ground connection of a tool one first end, and each this first and this second photoelectrical coupler drive circuit comprise a Zener diode, tool one anode and a negative electrode, wherein this negative electrode is coupled in this first end of this detecting current limiting resistance, one the 3rd resistance, tool one first end and one second end, wherein this first end is coupled in this anode of this Zener diode, one the 3rd transistor, tool one first end, one second end and a control end, wherein this first end is coupled in this ground connection, and this control end is coupled in this second end of the 3rd resistance, one the 4th resistance, tool one first end and one second end, wherein this first termination is received a supply voltage, and this second end is coupled in the 3rd transistorized this second end, one the 5th resistance, tool one first end and one second end, wherein this first end is coupled in this second end of the 4th resistance, one the 4th transistor, tool one first end, one second end and a control end, wherein this first end is coupled in this ground connection, and this control end is coupled in this second end of the 5th resistance, one the 6th resistance, tool one first end and one second end, wherein this first end is coupled in the 4th transistorized this second end, and this second end is exported this first or this second not conducting signal through shifting through shifting, one photoelectrical coupler, tool two inputs, one output and an earth terminal, wherein this two input be respectively applied for receive this DC power supply voltage and receive with transmit this through shifting first or should be through the second not conducting signal of transfer, this output is in order to export this first or second not conducting signal that should be through transmitting and shifting through transmitting and shifting, and one the 7th resistance, tool one first end and one second end, wherein this first end is coupled in this output, in order to receive this first or second not conducting signal that should be through transmitting and shifting through transmitting and shifting, and be coupled in this output node, in order to produce this first or this second the commutation detection signal, and this second end is respectively applied for and receives this supply voltage, to form a conductive path by this earth terminal, with this logic high state of output device this first or this second commutation detection signal, with form this logic low state of tool this first or this second commutation detection signal.

According to above-mentioned conception, this first with this second state be respectively a logic high and a logic low state, each this first and this second not conducting signal amplifier circuit comprise the detecting current limiting resistance and a ground connection of a tool one first end, and each this first and this second photoelectrical coupler drive circuit comprise one the 3rd resistance, tool one first end and one second end, wherein this first end is coupled in this first end of this detecting current limiting resistance, one the 3rd transistor, tool one first end, one second end and a control end, wherein this first end is coupled in this ground connection, and this control end is coupled in this second end of the 3rd resistance, one the 4th resistance, tool one first end and one second end, wherein this first termination is received a supply voltage, and this second end is coupled in the 3rd transistorized this second end, one the 5th resistance, tool one first end and one second end, wherein this first end is coupled in this second end of the 4th resistance, one the 4th transistor, tool one first end, one second end and a control end, wherein this first end is coupled in this ground connection, and this control end is coupled in this second end of the 5th resistance, one the 6th resistance, tool one first end and one second end, wherein this first end is coupled in the 4th transistorized this second end, and this second end is exported this first or this second not conducting signal through shifting through shifting, one photoelectrical coupler, tool two inputs, one output and an earth terminal, wherein this two input be respectively applied for receive this DC power supply voltage and receive with transmit this through shifting first or should be through the second not conducting signal of transfer, this output is in order to export this first or second not conducting signal that should be through transmitting and shifting through transmitting and shifting, and one the 7th resistance, tool one first end and one second end, wherein this first end is coupled in this output, in order to receive this first or second not conducting signal that should be through transmitting and shifting through transmitting and shifting, and be coupled in this output node, in order to produce this first or this second the commutation detection signal, and this second end is respectively applied for and receives this supply voltage, to form a conductive path by this earth terminal, with this logic high state of output device this first or this second commutation detection signal, with form this logic low state of tool this first or this second commutation detection signal.

According to above-mentioned conception, this first with this second state be respectively a logic high and a logic low state, each this first and this second not conducting signal amplifier circuit comprise the detecting current limiting resistance and a ground connection of a tool one first end, and each this first and this second photoelectrical coupler drive circuit comprise a Zener diode, tool one anode and a negative electrode, wherein this negative electrode is coupled in this first end of this detecting current limiting resistance, one first resistance, tool one first end and one second end, wherein this first end is coupled in this anode of this Zener diode, one the first transistor, tool one first end, one second end and a control end, wherein this first end is coupled in this ground connection, and this control end is coupled in this second end of this first resistance, one second resistance, tool one first end and one second end, wherein this first termination is received this supply voltage, and this second end is coupled in this second end of this first transistor, one the 3rd resistance, tool one first end and one second end, wherein this first end is coupled in this second end of this second resistance, one transistor seconds, tool one first end, one second end and a control end, wherein this first end is coupled in this ground connection, and this control end is coupled in this second end of the 3rd resistance, and one the 4th resistance, tool one first end and one second end, wherein this first end is coupled in this second end of this transistor seconds, and this second end is exported this first or this second not conducting signal through shifting through shifting, one photoelectrical coupler, tool two inputs, one output and an earth terminal, wherein this two input be respectively applied for receive this DC power supply voltage and receive with transmit this through shifting first or should be through the second not conducting signal of transfer, this output is in order to export this first or second not conducting signal that should be through transmitting and shifting through transmitting and shifting, and one the 5th resistance, tool one first end and one second end, wherein this first end is coupled in this output, in order to receive this first or second not conducting signal that should be through transmitting and shifting through transmitting and shifting, and be coupled in this output node, in order to produce this first or this second the commutation detection signal, and this second end is respectively applied for and receives this supply voltage, to form a conductive path by this earth terminal, with this logic high state of output device this first or this second commutation detection signal, with form this logic low state of tool this first or this second commutation detection signal.

According to above-mentioned conception, this first with this second state be respectively a logic high and a logic low state, each this first and this second not conducting signal amplifier circuit comprise the detecting current limiting resistance and a ground connection of a tool one first end, and each this first and this second photoelectrical coupler drive circuit comprise one first resistance, tool one first end and one second end, wherein this first end is coupled in this first end of this detecting current limiting resistance, one the first transistor, tool one first end, one second end and a control end, wherein this first end is coupled in this ground connection, and this control end is coupled in this second end of this first resistance, one second resistance, tool one first end and one second end, wherein this first termination is received this supply voltage, and this second end is coupled in this second end of this first transistor, one the 3rd resistance, tool one first end and one second end, wherein this first end is coupled in this second end of this second resistance, one transistor seconds, tool one first end, one second end and a control end, wherein this first end is coupled in this ground connection, and this control end is coupled in this second end of the 3rd resistance, and one the 4th resistance, tool one first end and one second end, wherein this first end is coupled in this second end of this transistor seconds, and this second end is exported this first or this second not conducting signal through shifting through shifting, one photoelectrical coupler, tool two inputs, one output and an earth terminal, wherein this two input be respectively applied for receive this DC power supply voltage and receive with transmit this through shifting first or should be through the second not conducting signal of transfer, this output is in order to export this first or second not conducting signal that should be through transmitting and shifting through transmitting and shifting, and one the 5th resistance, tool one first end and one second end, wherein this first end is coupled in this output, in order to receive this first or second not conducting signal that should be through transmitting and shifting through transmitting and shifting, and be coupled in this output node, in order to produce this first or this second the commutation detection signal, and this second end is respectively applied for and receives this supply voltage, to form a conductive path by this earth terminal, with this logic high state of output device this first or this second commutation detection signal, with form this logic low state of tool this first or this second commutation detection signal.

A main purpose more of the present invention is to provide a kind of circuit for detecting commutation failure that is used for a back-to-back silicon-control rectifying circuit, comprise one first detection signal generator, be coupled in this back-to-back silicon-control rectifying circuit, in order in a negative half period of AC-input voltage time detecting one commutation, and comprise one first not conducting signal amplifier circuit, not conducting when this back-to-back silicon-control rectifying circuit this negative half period in this AC-input voltage, then produce one first not conducting signal, and comprise one first not conducting signal amplifier, it amplifies this first not conducting signal.

According to above-mentioned conception, circuit for detecting, more comprise one second detection signal generator, be coupled in this back-to-back silicon-control rectifying circuit, in order to detecting one commutation when the positive half cycle of an AC-input voltage, and comprise one second not conducting signal amplifier circuit, not conducting when this back-to-back silicon-control rectifying circuit this positive half cycle in this AC-input voltage, then produce one second not conducting signal, and comprise one second not conducting signal amplifier, it amplifies this second not conducting signal, one first photoelectrical coupler drive circuit, its reception, shift and transmit this first not conducting signal, when this first not conducting signal does not exist, in order to produce the first commutation detection signal of a tool one first state, one second photoelectrical coupler drive circuit, its reception, shift and transmit this second not conducting signal, when this second not conducting signal does not exist, in order to produce the second commutation detection signal of this first state of a tool, an and output node, be coupled in this first and this second photoelectrical coupler drive circuit, in order to export this first or this second the commutation detection signal, wherein when this first not conducting signal exists, this first commutation detection signal is in one second state, and when this second not conducting signal existed, this second commutation detection signal was in this second state.

Next main purpose of the present invention is to provide a kind of control method that is used for the circuit for detecting commutation failure of a back-to-back silicon-control rectifying circuit, wherein this back-to-back silicon-control rectifying circuit comprises one first and one second thyristor, has a negative electrode separately, this circuit for detecting commutation failure comprises one first and one second not conducting signal amplifier circuit, be coupled in the described negative electrode of this first and second thyristor separately, one first and one second not conducting signal driver, be coupled in separately this first and this second not conducting signal amplifier circuit, and one first and one second not conducting signal isolator, be coupled in separately this first and this second not conducting signal driver, this method comprises following step: (a) make a forward voltage put on this first and this second thyristor; (b) be higher than one second potential voltage of this negative electrode of this second thyristor at one first potential voltage of this negative electrode of this first thyristor, this is first and all not conductings of this second thyristor years old, and when this first and during a positive half cycle of an AC-input voltage of this second thyristor, this second not conducting signal amplifier circuit is activated, start this second not conducting signal driver according to this, cause the commutation detection signal that this second not conducting signal isolator output has one first state; And (c) equal this forward voltage in the difference of this first potential voltage and this second potential voltage, this is first or this second thyristor conducting years old, and when this first and during this positive half cycle of an AC-input voltage of this second thyristor, this second not conducting signal amplifier circuit is turned off, turn-off this second not conducting signal driver according to this, cause this second not conducting signal isolator output and have this commutation detection signal of one second state.

According to above-mentioned conception, this first with this second state be respectively a logic low and a logic high state, this control method more comprises following step: (d) be higher than this first potential voltage at this second potential voltage, this is first and all not conductings of this second thyristor years old, and when this first and during a negative half period of this AC-input voltage of this second thyristor, this first not conducting signal amplifier circuit is activated, start this first not conducting signal driver according to this, cause this first not conducting signal isolator output and have this commutation detection signal of this logic low state; And (e) equal this forward voltage in the difference of this second potential voltage and this first potential voltage, this is first or this second thyristor conducting years old, and when this first and during this negative half period of an AC-input voltage of this second thyristor, this first not conducting signal amplifier circuit is turned off, turn-off this first not conducting signal driver according to this, cause this first not conducting signal isolator output and have this commutation detection signal of this logic high state.

According to above-mentioned conception, this control method comprises that more this first not conducting signal amplifier circuit comprises one first and one transistor seconds, this first not conducting signal driver comprises one the 3rd and one the 4th transistor, and this first not conducting signal isolator comprises that one has the photoelectrical coupler of two inputs, and this step (d) more comprises following step: (d1) because this first potential voltage is higher than this second potential voltage, this the first transistor is activated, and this transistor seconds of bias voltage according to this, and this transistor seconds is activated; And (d2) the 3rd transistor is turned off, and make this two input and the 4th transistor form a conductive path, cause this photoelectrical coupler output and have this commutation detection signal of this logic low state, wherein this step (e) more comprises following step: (e1) because the difference of this second potential voltage and this first potential voltage equals this forward voltage, this the first transistor is turned off, and turn-offs this transistor seconds according to this; And (e2) the 3rd transistor is activated, making the 4th a transistorized base current is zero, and makes this two input form an open circuit, causes this photoelectrical coupler output and has this commutation detection signal of this logic high state.

According to above-mentioned conception, this first state is a logic low state, this second not conducting signal amplifier circuit comprises one first and one transistor seconds, this second not conducting signal driver comprises one the 3rd and one the 4th transistor, and this second not conducting signal isolator comprises that one has the photoelectrical coupler of two inputs, this step (b) more comprises following step: (b1) because this first potential voltage is higher than this second potential voltage, this the first transistor is activated, and this transistor seconds of bias voltage according to this, and this transistor seconds is activated; And (b2) the 3rd transistor is turned off, and makes this two input and the 4th transistor form a conductive path, cause this photoelectrical coupler output and have this commutation detection signal of this logic low state.

According to above-mentioned conception, this second state is a logic high state, this step (c) more comprises following step: (c1) because the difference of this first potential voltage and this second potential voltage equals this forward voltage, this first transistor is turned off, and turn-offs this transistor seconds according to this; And (c2) the 3rd transistor is activated, making the 4th a transistorized base current is zero, and makes this two input form an open circuit, causes this photoelectrical coupler output and has this commutation detection signal of this logic high state.

Description of drawings

Fig. 1 is for showing the circuit diagram of a traditional voltage regulating transformer;

Fig. 2 is for showing that one is used for the calcspar of the circuit for detecting commutation failure of traditional use bridge circuit of a back-to-back silicon-control rectifying circuit and photoelectrical coupler;

Fig. 3 is for showing that one is used for the calcspar of circuit for detecting commutation failure of traditional use photoelectrical coupler of a back-to-back silicon-control rectifying circuit;

Fig. 4 is the circuit diagram of demonstration one according to the circuit for detecting commutation failure that is used for a back-to-back silicon-control rectifying circuit of first preferred embodiment of the present invention's conception;

Fig. 5 is the circuit diagram of demonstration one according to the circuit for detecting commutation failure that is used for a back-to-back silicon-control rectifying circuit of second preferred embodiment of the present invention's conception;

Fig. 6 is the controlling signal separately in respect of time oscillogram of demonstration one according to the electric current and the T7 collection utmost point as shown in Figure 4 of the cross-pressure of the thyristor of first preferred embodiment of the present invention's conception, the thyristor of flowing through; And

Fig. 7 is the controlling signal separately in respect of time oscillogram of demonstration one according to the electric current and the D2 negative electrode as shown in Figure 5 of the cross-pressure of the thyristor of second preferred embodiment of the present invention's conception, the thyristor of flowing through.

Embodiment

Please referring to Fig. 4, its demonstration one is according to the circuit diagram of the circuit for detecting commutation failure that is used for a back-to-back silicon-control rectifying circuit of first preferred embodiment of the present invention's conception.The circuit for detecting commutation failure 1 of the back-to-back silicon-control rectifying circuit that is provided comprises: one first detection signal generator, be coupled in a negative electrode of one first thyristor of this back-to-back silicon-control rectifying circuit (not manifesting) at a connector K2 place, in order in a negative half period of AC-input voltage time detecting one commutation, and comprise one first not conducting signal amplifier circuit 11, be used for when the back-to-back not conducting of silicon-control rectifying circuit of this negative half period of this AC-input voltage and this, produce one first not conducting signal, one first not conducting signal driver 13, in order to receive and to shift this first not conducting signal, and one first not conducting signal isolator, comprise one first an optical coupler U1 and a resistance R 9, in order to receive this not conducting signal through shifting, and when not having this first not conducting signal, generation one is in the first commutation detection signal of a logic high state; One second detection signal generator, be coupled in a negative electrode of one second thyristor of this back-to-back silicon-control rectifying circuit at a connector K1 place, in order to detect this commutation when the positive half cycle of this AC-input voltage, and comprise one second not conducting signal amplifier circuit 12, be used for when the back-to-back not conducting of silicon-control rectifying circuit of this positive half cycle of this AC-input voltage and this, produce one second not conducting signal, one second not conducting signal driver 14, in order to receive and to shift this second not conducting signal, and one second not conducting signal isolator, comprise one second an optical coupler U2 and a resistance R 18, in order to receive this second not conducting signal through shifting, and when not having this second not conducting signal, generation one is in the second commutation detection signal of a logic high state; And an output node (being linked to this) to the microprocessor connector, be coupled in this first and this second not conducting signal isolator, in order to export this first or this second commutation detection signal.

Wherein, this first not conducting signal amplifier circuit 11 comprises: a signal bias resistance R 4, one detecting current limiting resistance R5, an one reverse obstruct diode D3 and a signal amplifier 111, comprise: a first order, tool one transistor T 1 and a resistance R 11, and a second level, tool one transistor T 3 and a resistance R 10.This second not conducting signal amplifier circuit 12 comprises: a signal bias resistance R 13, one detecting current limiting resistance R14, an one reverse obstruct diode D5 and a signal amplifier 121, comprise: a first order, tool one transistor T 5 and a resistance R 20, and a second level, tool one transistor T 7 and a resistance R 19.This first not conducting signal driver 13 comprises: a Zener diode D4 (it is an option, can be omitted in a different preferred embodiment), a resistance R 12, one transistor Ts 4, one resistance R 6, one resistance R 7, one transistor Ts 2, and a resistance R 8.And this second not conducting signal driver 14 comprises: a Zener diode D6 (it also is an option, can be omitted in another different preferred embodiment), a resistance R 21, one transistor T, 8, one resistance R, 15, one resistance R 16, one transistor T 6, and a resistance R 17.

Suppose that the first thyristor SCR1 (not shown) that a thyristor of this back-to-back silicon controlled rectifier circuit is right when this AC-input voltage (not shown) of this back-to-back silicon controlled rectifier circuit is this positive half cycle, is triggered in some firing angle.It is right that one forward voltage is presented in this thyristor, till this thyristor begins conducting to wherein arbitrary thyristor.

When this positive half cycle, the potential voltage of K2 is higher than the potential voltage of K1.This positive potential is activated this transistor T 5, and transistor T 5 bias voltage T7 immediately makes its startup.Therefore, whole voltage puts on the combination of parallel resistance: R14, R19 and R20, and the collection utmost point of transistor T 7 is pulled low to earthing potential.During this period, transistor T 8 turn-offs.The photodiode of this U2 sees through transistor T 6 and conducting, causes the logic low state that exports to of switches light electric coupling U2.

In the conduction period of thyristor, the potential difference between K2 and K1 end points equals the forward drop of thyristor.This voltage is very little, so transistor T 5 is switched to shutoff with T7.One direct current power supply (Vcc2 ,+5V) drive this transistor T 8 to make its startup, and transistor T 6 is turn-offed.Therefore, during one, the photodiode of this U2 is opened a way at this, and its output is a logic high state.

Negative half period in this AC-input voltage, to this first half according to the circuit for detecting commutation failure that is used for a back-to-back silicon-control rectifying circuit of first preferred embodiment of the present invention's conception, the analysis of its operation principles, also be similar (this moment this DC power supply then be: Vcc1 ,+5V).

In this circuit, the obstruct voltage under the thyristor turn-off criterion is to be used for driving a transistor it is activated, and this transistor is transferred to amplify a not conducting signal and started partial transistor.Therefore, the flow through electric current of this electric current limiting resistance does not directly involve in the acquisition of commutation information.Consequently, the commutation of a thyristor can lingeringly be sensed by only tool is minimum.

Please referring to Fig. 5, its demonstration one is according to the circuit diagram of the circuit for detecting commutation failure that is used for a back-to-back silicon-control rectifying circuit of second preferred embodiment of the present invention's conception.The circuit for detecting commutation failure 2 of the back-to-back silicon-control rectifying circuit that is provided comprises: one first detection signal generator, be coupled in a negative electrode of one first thyristor of this back-to-back silicon-control rectifying circuit (not manifesting) at a connector K2 place, in order in a negative half period of AC-input voltage time detecting one commutation, and comprise one first not conducting signal amplifier circuit 21, be used for when the back-to-back not conducting of silicon-control rectifying circuit of this negative half period of this AC-input voltage and this, produce one first not conducting signal, one first not conducting signal driver 13, in order to receive and to shift this first not conducting signal, and one first not conducting signal isolator, comprise one first an optical coupler U1 and a resistance R 9, in order to receive this not conducting signal through shifting, and when not having this first not conducting signal, generation one is in the first commutation detection signal of a logic high state; One second detection signal generator, be coupled in a negative electrode of one second thyristor of this back-to-back silicon-control rectifying circuit at a connector K1 place, in order to detect this commutation when the positive half cycle of this AC-input voltage, and comprise one second not conducting signal amplifier circuit 22, be used for when the back-to-back not conducting of silicon-control rectifying circuit of this positive half cycle of this AC-input voltage and this, produce one second not conducting signal, one second not conducting signal driver 14, in order to receive and to shift this second not conducting signal, and one second not conducting signal isolator, comprise one second an optical coupler U2 and a resistance R 18, in order to receive this second not conducting signal through shifting, and when not having this second not conducting signal, generation one is in the second commutation detection signal of a logic high state; And an output node (being linked to this) to the microprocessor connector, be coupled in this first and this second not conducting signal isolator, in order to export this first or this second commutation detection signal.

In Fig. 5, this first not conducting signal amplifier circuit 21 comprises: a signal bias resistance R 4, one detecting current limiting resistance R5, a reverse obstruct diode D3 and a signal amplify diode D1.This second not conducting signal amplifier circuit 22 comprises: a signal bias resistance R 13, one detecting current limiting resistance R14, a reverse obstruct diode D5 and a signal amplify diode D2.This first not conducting signal driver 13 is identical with these drivers among this second not conducting signal driver 14 and Fig. 4.

Suppose that the first thyristor (not shown) that a thyristor of this back-to-back silicon controlled rectifier circuit is right when this AC-input voltage (not shown) of this back-to-back silicon controlled rectifier circuit is this positive half cycle, is triggered in some firing angle.It is right that then a forward voltage is presented in this thyristor, till this thyristor begins conducting to wherein arbitrary thyristor.

When this positive half cycle, the potential voltage of K2 is higher than the potential voltage of K1.This positive potential is activated this diode D2.Therefore, whole voltage puts on resistance R 14.During one, transistor T 8 turn-offs at this.The photodiode of this U2 sees through transistor T 6 and conducting, causes the logic low state that exports to of switches light electric coupling U2.

In the conduction period of thyristor, the potential difference between K2 and K1 end points equals the forward drop of thyristor.This voltage is very little, so diode D2 is switched to shutoff.One direct current power supply (Vcc2 ,+5V) drive this transistor T 8 to make its startup, and transistor T 6 is turn-offed.Therefore, during this period, the photodiode of this U2 is opened a way, and its output is a logic high state.

Negative half period in this AC-input voltage, to this first half according to the circuit for detecting commutation failure that is used for a back-to-back silicon-control rectifying circuit of second preferred embodiment of the present invention's conception, the analysis of its operation principles, also be similar (this moment this DC power supply then be: Vcc1 ,+5V).

Basically, because

signal amplifier

111 and 121 is replaced by diode D1 and D2, this than this circuit for detecting commutation failure 1 according to the back-to-back silicon-control rectifying circuit of first preferred embodiment of the present invention's conception, has better simply relatively framework according to the circuit for detecting commutation failure 2 of the back-to-back silicon-control rectifying circuit of second preferred embodiment of the present invention conception.But in the delay of the zero current crossover point of the circuit for detecting commutation failure that is used for a back-to-back silicon-control rectifying circuit 2 of second preferred embodiment of foundation the present invention conception, than this delay according to the zero current crossover point of the circuit for detecting commutation failure 1 of the back-to-back silicon-control rectifying circuit of first preferred embodiment of the present invention's conception come long a little a bit.

For showing this point, in the formed load of fluorescent lamp of the bulb and a 40W of a tool one 60 watts (W), and this I/P voltage is to have carried out a test on the single thyristor of 240V.Please referring to Fig. 6, its demonstration one is according to the controlling signal oscillogram in respect of time separately of the electric current and the T7 collection utmost point as shown in Figure 4 of the cross-pressure of the thyristor of first preferred embodiment of the present invention's conception, the thyristor of flowing through.Please referring to Fig. 7, its demonstration one is according to the controlling signal oscillogram in respect of time separately of the electric current and the D2 negative electrode as shown in Figure 5 of the cross-pressure of the thyristor of second preferred embodiment of the present invention's conception, the thyristor of flowing through.See Fig. 6 and Fig. 7, Ch1 represents the cross-pressure of thyristor separately, and Ch2 represents the electric current of the thyristor of flowing through separately, and Ch3 represents separately as Fig. 4 and the T7 collection utmost point shown in Figure 5 or the controlling signal of D2 negative electrode.In Fig. 7, have one between its zero current crossover point and the controlling signal that is triggered and postpone more significantly.Yet, among Fig. 6, the delay between its zero current crossover point and the controlling signal that is triggered, relatively very not remarkable.

By above-mentioned explanation as can be known, circuit for detecting commutation failure that this case provided and control method thereof have: can make the advantage of the delay minimization that circuit for detecting commutation failure presented of back-to-back silicon-control rectifying circuit.

Therefore; even if this case is described in detail by the above embodiments and can makes various corresponding changes and distortion according to the present invention by those of ordinary skill in the art, but these corresponding changes and distortion all should belong to the protection range of the appended claim of the present invention.

Claims

1. circuit for detecting commutation failure that is used for a back-to-back silicon-control rectifying circuit comprises:

One first detection signal generator is coupled in this back-to-back silicon-control rectifying circuit, in order in a negative half period of AC-input voltage time detecting one commutation, comprising:

One first not conducting signal amplifier circuit, not conducting when this negative half period in this AC-input voltage of this back-to-back silicon-control rectifying circuit then produces one first not conducting signal;

One first not conducting signal driver receives and shifts this first not conducting signal; And

One first not conducting signal isolator receives this first not conducting signal through shifting, when this first not conducting signal does not exist, in order to produce one first commutation detection signal of tool one first state; And

One second detection signal generator is coupled in this back-to-back silicon-control rectifying circuit, in order to detect this commutation when the positive half cycle of this AC-input voltage, comprising:

One second not conducting signal amplifier circuit, not conducting when this positive half cycle in this AC-input voltage of this back-to-back silicon-control rectifying circuit then produces one second not conducting signal;

One second not conducting signal driver receives and shifts this second not conducting signal; And

One second not conducting signal isolator receives this second not conducting signal through shifting, when this second not conducting signal does not exist, in order to produce one second commutation detection signal of this first state of tool.

2. circuit for detecting as claimed in claim 1, more comprise an output node, be coupled in this first and this second not conducting signal isolator, in order to export this first or this second the commutation detection signal, wherein when this first not conducting signal exists, this first commutation detection signal is in one second state, and when this second not conducting signal exists, this second commutation detection signal is in this second state, wherein this first is respectively a logic high and a logic low state with this second state, each this first and this second not conducting signal isolator comprise:

One photoelectrical coupler, tool two inputs, an output and an earth terminal, wherein this two input is respectively applied for and receives a direct current supply voltage and receive and transmit this first or second not conducting signal that should be through shifting through shifting, this output in order to export this through transmitting and shifting first or should be through transmitting and the second not conducting signal of transfer; And

One first resistance, tool one first end and one second end, wherein this first end is coupled in this output, in order to receive this first or second not conducting signal that should be through transmitting and shifting through transmitting and shifting, and be coupled in this output node, in order to produce this first or this second the commutation detection signal, and this second end is respectively applied for and receives this DC power supply voltage, to form a conductive path by this earth terminal, with this logic high state of output device this first or this second commutation detection signal, with form this logic low state of tool this first or this second commutation detection signal.

3. circuit for detecting as claimed in claim 1, wherein this back-to-back silicon-control rectifying circuit comprises one first and one second thyristor, has a negative electrode separately, this first not conducting signal amplifier which couple is in this negative electrode of this first thyristor, this second not conducting signal amplifier which couple is in this negative electrode of this second thyristor, and each this first comprise with this second not conducting signal amplifier circuit:

One signal bias resistance, tool one first end is coupled in a direct current supply voltage, in order to forming a not conducting signal bias, and one second end;

One detecting current limiting resistance, tool one first end is coupled in this second end of this signal bias resistance, in order to limiting a detecting current of flowing through this detecting current limiting resistance, and one second end;

One reverse obstruct diode, tool one anode is coupled in this second end of this detecting current limiting resistance, and a negative electrode be coupled in this first or the described negative electrode of this second thyristor, in order to prevent a revers voltage; And

One signal amplifier, amplify this first or this second not conducting signal, comprising:

One first order comprises:

One the first transistor, tool one first end, one second end and a control end, wherein this first end is coupled in this anode of this reverse obstruct diode; And

One first resistance, tool one first end and one second end, wherein this first end is coupled in this control end of this first transistor, and this second end be coupled in this first or the described negative electrode of this second thyristor; And

One second level comprises:

One transistor seconds, tool one first end, one second end and a control end, wherein this first end is coupled in this second end and a ground connection of this first resistance, and this second end is coupled in this first end of this detecting current limiting resistance; And

One second resistance, tool one first end and one second end, wherein this first end is coupled in this control end of this transistor seconds, and this second end is coupled in this second end of this first transistor.

4. circuit for detecting as claimed in claim 3, wherein each this first comprise with this second not conducting signal driver:

One Zener diode, tool one anode and a negative electrode, wherein this negative electrode is coupled in this first end of this detecting current limiting resistance;

One the 3rd resistance, tool one first end and one second end, wherein this first end is coupled in this anode of this Zener diode;

One the 3rd transistor, tool one first end, one second end and a control end, wherein this first end is coupled in this ground connection, and this control end is coupled in this second end of the 3rd resistance;

One the 4th resistance, tool one first end and one second end, wherein this first termination is received this DC power supply voltage, and this second end is coupled in the 3rd transistorized this second end;

One the 5th resistance, tool one first end and one second end, wherein this first end is coupled in this second end of the 4th resistance;

One the 4th transistor, tool one first end, one second end and a control end, wherein this first end is coupled in this ground connection, and this control end is coupled in this second end of the 5th resistance; And

One the 6th resistance, tool one first end and one second end, wherein this first end is coupled in the 4th transistorized this second end, and this second end is exported this first or this second not conducting signal through shifting through shifting.

5. circuit for detecting as claimed in claim 3, wherein each this first comprise with this second not conducting signal driver:

One the 3rd resistance, tool one first end and one second end, wherein this first end is coupled in this first end of this detecting current limiting resistance;

6. circuit for detecting as claimed in claim 1, wherein this back-to-back silicon-control rectifying circuit comprises one first and one second thyristor, has a negative electrode separately, this first not conducting signal amplifier which couple is in this negative electrode of this first thyristor, this second not conducting signal amplifier which couple is in this negative electrode of this second thyristor, and each this first comprise with this second not conducting signal amplifier circuit:

One signal amplifier, amplify this first or this second not conducting signal, and comprise that one amplifies diode, tool one anode and a negative electrode, wherein this anode be coupled in a ground connection and be coupled in this first or the described negative electrode of this second thyristor, and this negative electrode is coupled in this first end of this detecting current limiting resistance.

7. circuit for detecting as claimed in claim 6, wherein each this first comprise with this second not conducting signal driver:

One first resistance, tool one first end and one second end, wherein this first end is coupled in this anode of this Zener diode;

One the first transistor, tool one first end, one second end and a control end, wherein this first end is coupled in this ground connection, and this control end is coupled in this second end of this first resistance;

One second resistance, tool one first end and one second end, wherein this first termination is received this DC power supply voltage, and this second end is coupled in this second end of this first transistor;

One the 3rd resistance, tool one first end and one second end, wherein this first end is coupled in this second end of this second resistance;

One transistor seconds, tool one first end, one second end and a control end, wherein this first end is coupled in this ground connection, and this control end is coupled in this second end of the 3rd resistance; And

One the 4th resistance, tool one first end and one second end, wherein this first end is coupled in this second end of this transistor seconds, and this second end export this through shifting first or should be through shifting the second not conducting signal.

8. circuit for detecting as claimed in claim 6, wherein each this first comprise with this second not conducting signal driver:

One first resistance, tool one first end and one second end, wherein this first end is coupled in this first end of this detecting current limiting resistance;

One the 4th resistance, tool one first end and one second end, wherein this first end is coupled in this second end of this transistor seconds, and this second end is exported this first or this second not conducting signal through shifting through shifting.

9. circuit for detecting commutation failure that is used for a back-to-back silicon-control rectifying circuit comprises:

One first not conducting signal amplifier circuit, not conducting when this back-to-back silicon-control rectifying circuit this negative half period in this AC-input voltage, then produce one first not conducting signal, and comprise one first not conducting signal amplifier, it amplifies this first not conducting signal; And

One second detection signal generator is coupled in this back-to-back silicon-control rectifying circuit, in order to detect this commutation when the positive half cycle of an AC-input voltage, comprising:

One second not conducting signal amplifier circuit, not conducting when this back-to-back silicon-control rectifying circuit this positive half cycle in this AC-input voltage, then produce one second not conducting signal, and comprise one second not conducting signal amplifier, it amplifies this second not conducting signal.

10. circuit for detecting as claimed in claim 9, more comprise one first photoelectrical coupler drive circuit, its reception, shift and transmit this first not conducting signal, when this first not conducting signal does not exist, in order to produce the first commutation detection signal of a tool one first state, one second photoelectrical coupler drive circuit, its reception, shift and transmit this second not conducting signal, when this second not conducting signal does not exist, in order to produce the second commutation detection signal of this first state of a tool, an and output node, be coupled in this first and this second photoelectrical coupler drive circuit, in order to export this first or this second the commutation detection signal, wherein when this first not conducting signal exists, this first commutation detection signal is in one second state, and when this second not conducting signal existed, this second commutation detection signal was in this second state.

11. circuit for detecting as claimed in claim 10, wherein this first with this second state be respectively a logic high and a logic low state, this first and this second not conducting signal amplifier circuit be in the circuit for detecting as claimed in claim 4 this first and this second not conducting signal amplifier circuit, each this first and this second not conducting signal amplifier circuit comprise the detecting current limiting resistance and a ground connection of a tool one first end, and each this first and this second photoelectrical coupler drive circuit comprise:

One the 4th resistance, tool one first end and one second end, wherein this first termination is received a direct current supply voltage, and this second end is coupled in the 3rd transistorized this second end;

One the 4th transistor, tool one first end, one second end and a control end, wherein this first end is coupled in this ground connection, and this control end is coupled in this second end of the 5th resistance;

One the 6th resistance, tool one first end and one second end, wherein this first end is coupled in the 4th transistorized this second end, and this second end is exported this first or this second not conducting signal through shifting through shifting;

One photoelectrical coupler, tool two inputs, an output and an earth terminal, wherein this two input is respectively applied for and receives this DC power supply voltage and receive and transmit this first or second not conducting signal that should be through shifting through shifting, this output in order to export this through transmitting and shifting first or should be through transmitting and the second not conducting signal of transfer; And

One the 7th resistance, tool one first end and one second end, wherein this first end is coupled in this output, in order to receive this first or second not conducting signal that should be through transmitting and shifting through transmitting and shifting, and be coupled in this output node, in order to produce this first or this second the commutation detection signal, and this second end is respectively applied for and receives this DC power supply voltage, to form a conductive path by this earth terminal, with this logic high state of output device this first or this second commutation detection signal, with form this logic low state of tool this first or this second commutation detection signal.

12. circuit for detecting as claimed in claim 10, wherein this first with this second state be respectively a logic high and a logic low state, this first and this second not conducting signal amplifier circuit be in the circuit for detecting as claimed in claim 4 this first and this second not conducting signal amplifier circuit, each this first and this second not conducting signal amplifier circuit comprise the detecting current limiting resistance and a ground connection of a tool one first end, and each this first and this second photoelectrical coupler drive circuit comprise:

13. circuit for detecting as claimed in claim 10, wherein this first with this second state be respectively a logic high and a logic low state, this first and this second not conducting signal amplifier circuit be in the circuit for detecting as claimed in claim 7 this first and this second not conducting signal amplifier circuit, each this first and this second not conducting signal amplifier circuit comprise the detecting current limiting resistance and a ground connection of a tool one first end, and each this first and this second photoelectrical coupler drive circuit comprise:

One the 4th resistance, tool one first end and one second end, wherein this first end is coupled in this second end of this transistor seconds, and this second end is exported this first or this second not conducting signal through shifting through shifting;

One the 5th resistance, tool one first end and one second end, wherein this first end is coupled in this output, in order to receive this first or second not conducting signal that should be through transmitting and shifting through transmitting and shifting, and be coupled in this output node, in order to produce this first or this second the commutation detection signal, and this second end is respectively applied for and receives this DC power supply voltage, to form a conductive path by this earth terminal, with this logic high state of output device this first or this second commutation detection signal, with form this logic low state of tool this first or this second commutation detection signal.

14. circuit for detecting as claimed in claim 10, wherein this first with this second state be respectively a logic high and a logic low state, this first and this second not conducting signal amplifier circuit be in the circuit for detecting as claimed in claim 7 this first and this second not conducting signal amplifier circuit, each this first and this second not conducting signal amplifier circuit comprise the detecting current limiting resistance and a ground connection of a tool one first end, and each this first and this second photoelectrical coupler drive circuit comprise:

15. circuit for detecting commutation failure that is used for a back-to-back silicon-control rectifying circuit, comprise one first detection signal generator, be coupled in this back-to-back silicon-control rectifying circuit, in order in a negative half period of AC-input voltage time detecting one commutation, and comprise one first not conducting signal amplifier circuit, not conducting when this back-to-back silicon-control rectifying circuit this negative half period in this AC-input voltage, then produce one first not conducting signal, and comprise one first not conducting signal amplifier, it amplifies this first not conducting signal.

16. circuit for detecting as claimed in claim 15, more comprise one second detection signal generator, be coupled in this back-to-back silicon-control rectifying circuit, in order to detecting one commutation when the positive half cycle of an AC-input voltage, and comprise one second not conducting signal amplifier circuit, not conducting when this back-to-back silicon-control rectifying circuit this positive half cycle in this AC-input voltage, then produce one second not conducting signal, and comprise one second not conducting signal amplifier, it amplifies this second not conducting signal, one first photoelectrical coupler drive circuit, its reception, shift and transmit this first not conducting signal, when this first not conducting signal does not exist, in order to produce the first commutation detection signal of a tool one first state, one second photoelectrical coupler drive circuit, its reception, shift and transmit this second not conducting signal, when this second not conducting signal does not exist, in order to produce the second commutation detection signal of this first state of a tool, an and output node, be coupled in this first and this second photoelectrical coupler drive circuit, in order to export this first or this second the commutation detection signal, wherein when this first not conducting signal exists, this first commutation detection signal is in one second state, and when this second not conducting signal existed, this second commutation detection signal was in this second state.

17. control method that is used for the circuit for detecting commutation failure of a back-to-back silicon-control rectifying circuit, wherein this back-to-back silicon-control rectifying circuit comprises one first and one second thyristor, has a negative electrode separately, this circuit for detecting commutation failure comprises one first and one second not conducting signal amplifier circuit, be coupled in separately this first and the described negative electrode of this second thyristor, one first and one second not conducting signal driver, be coupled in separately this first and this second not conducting signal amplifier circuit, and one first and one second not conducting signal isolator, be coupled in separately this first and this second not conducting signal driver, this method comprises following step:

(a) make a forward voltage put on this first and this second thyristor;

(b) be higher than one second potential voltage of this negative electrode of this second thyristor at one first potential voltage of this negative electrode of this first thyristor, this is first and all not conductings of this second thyristor years old, and when this first and during a positive half cycle of an AC-input voltage of this second thyristor, this second not conducting signal amplifier circuit is activated, start this second not conducting signal driver according to this, cause the commutation detection signal that this second not conducting signal isolator output has one first state; And

(c) difference at this first potential voltage and this second potential voltage equals this forward voltage, this is first or this second thyristor conducting years old, and when this first and during this positive half cycle of an AC-input voltage of this second thyristor, this second not conducting signal amplifier circuit is turned off, turn-off this second not conducting signal driver according to this, cause this second not conducting signal isolator output and have this commutation detection signal of one second state.

18. control method as claimed in claim 17, wherein this first with this second state be respectively a logic low and a logic high state, more comprise following step:

(d) be higher than this first potential voltage at this second potential voltage, this is first and all not conductings of this second thyristor years old, and when this first and during a negative half period of this AC-input voltage of this second thyristor, this first not conducting signal amplifier circuit is activated, start this first not conducting signal driver according to this, cause this first not conducting signal isolator output and have this commutation detection signal of this logic low state; And

(e) difference at this second potential voltage and this first potential voltage equals this forward voltage, this is first or this second thyristor conducting years old, and when this first and during this negative half period of an AC-input voltage of this second thyristor, this first not conducting signal amplifier circuit is turned off, turn-off this first not conducting signal driver according to this, cause this first not conducting signal isolator output and have this commutation detection signal of this logic high state, wherein this first not conducting signal amplifier circuit is this first not conducting signal amplifier circuit in the circuit for detecting as claimed in claim 3, and comprise one first and one transistor seconds, this first not conducting signal driver is this first not conducting signal driver in the circuit for detecting as claimed in claim 4, and comprise one the 3rd and one the 4th transistor, and this first not conducting signal isolator is this first not conducting signal isolator in the circuit for detecting as claimed in claim 3, and comprise that one has the photoelectrical coupler of two inputs, and this step (d) more comprises following step:

(d1) because this second potential voltage is higher than this first potential voltage, this first transistor is activated, and this transistor seconds of bias voltage according to this, and this transistor seconds is activated; And

(d2) the 3rd transistor is turned off, and makes this two input and the 4th transistor form a conductive path, cause this photoelectrical coupler output and have this commutation detection signal of this logic low state, wherein this step (e) more comprises following step:

(e1) because the difference of this second potential voltage and this first potential voltage equals this forward voltage, this first transistor is turned off, and turn-offs this transistor seconds according to this; And

(e2) the 3rd transistor is activated, making the 4th a transistorized base current is zero, and makes this two input form an open circuit, causes this photoelectrical coupler output and has this commutation detection signal of this logic high state.

19. control method as claimed in claim 17, wherein this first state is a logic low state, this second not conducting signal amplifier circuit is this second not conducting signal amplifier circuit in the circuit for detecting as claimed in claim 3, and comprise one first and one transistor seconds, this second not conducting signal driver is this second not conducting signal driver in the circuit for detecting as claimed in claim 4, and comprise one the 3rd and one the 4th transistor, and this second not conducting signal isolator is this second not conducting signal isolator in the circuit for detecting as claimed in claim 2, and comprise that one has the photoelectrical coupler of two inputs, this step (b) more comprises following step:

(b1) because this first potential voltage is higher than this second potential voltage, this first transistor is activated, and this transistor seconds of bias voltage according to this, and this transistor seconds is activated; And

(b2) the 3rd transistor is turned off, and make this two input and the 4th transistor form a conductive path, cause this photoelectrical coupler output and have this commutation detection signal of this logic low state, wherein this second state is a logic high state, and this step (c) more comprises following step:

(c1) because the difference of this first potential voltage and this second potential voltage equals this forward voltage, this first transistor is turned off, and turn-offs this transistor seconds according to this; And

(c2) the 3rd transistor is activated, making the 4th a transistorized base current is zero, and makes this two input form an open circuit, causes this photoelectrical coupler output and has this commutation detection signal of this logic high state.