JP2716778B2 - Thyristor device control circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a control device for a thyristor device,
In particular, the present invention relates to a phase control device considering its reliability.

(Prior Art) A thyristor rectifier is applied in a wide range of industrial fields for the purpose of controlling and rectifying an AC power supply to control power supplied to a DC load.

In order to control the output power of the thyristor rectifier, a phase control device that generates a thyristor firing pulse synchronized with the phase angle of the AC power supply voltage is used. However, if high reliability is required, a dual phase control device is required. Is being done. This means that one of the two phase controllers is a regular system,
The other is a standby system, and the normal system is used during normal operation, and if the normal system fails, the system is switched to the standby system.

FIG. 6 shows a configuration diagram of a conventional dual phase control device. Thyristor rectifier 1 is a three-phase AC power supply 2
To supply DC power to the load 3 by three-phase uniform bridge connection by six thyristor elements 1u, 1v, 1w, 1x, 1y, 1z. Controller 4 is provided for the purpose of controlling the DC power supplied to the load 3, provides a phase control command theta _s phase control device 5a, against 5b. The phase control device 5a includes a phase detection unit 6a, a comparison unit 7a, and a pulse width limitation unit 8a.
Consists of The phase detector 6a detects the voltage phase of the three-phase AC power supply 2, and corresponds to the thyristor elements 1u, 1v, 1w, 1x, 1y, 1z, that is, the phase angle signals θ _ua , θ having a phase difference of 60 °.
_va , θ _wa , θ _xa , θ _ya , θ _za , and the comparing unit 7a compares the phase angle signal θ _ua with the phase control command θ _s, and outputs the phase angle signal θ _ua
Is greater than the pulse output condition F _ua , the pulse output condition F _ua is output, and the phase output signals θ _va , θ _wa , θ _xa , θ _ya , and θ _za are similarly compared with the phase control command θ _s , Condition F _va , F _wa , F
Output _xa , F _ya , F _za .

When the pulse output condition F _ua changes from invalid to valid, the pulse width limiting section 8a outputs a pulse P _ua having a predetermined width, and the pulse output condition F _va , F _wa , F _xa , F _ya , F _za Similarly, pulses P _va , P _wa , P _xa , P _ya , and P _za are output. Phase controller 5b
Has the same configuration as the phase control device 5a and performs the same operation.

The failure detector 9 outputs a pulse P which is an output of the phase control device 5a.
_{ua, P va, P wa,} P xa, P ya, when it is detected that more than any one of P _za stops, switches the switching contact 10. The switching contact 10 is configured to normally transmit the output of the phase control device 5a to the thyristor rectifier 1, and to transmit the output of the phase control device 5b to the thyristor rectifier 1 when the failure detector 9 detects an abnormality. I have.

FIG. 7 is a waveform diagram for explaining the operation of the phase control device 5a. Only signals related to the thyristor element 1u are shown for clarity of description. The AC power supply voltage Eu shown in FIG.
, And the phase angle signal θ _ua output from the phase detector 6a is a phase angle of 0 ° to 36 ° in one cycle of Eu.
Indicates a value proportional to 0 ゜.

Comparing portion 7a pulse output condition F _ua which becomes effective when θ _{s <θ ua} by comparing the phase control command theta _s and the phase angle signal theta _ua
For outputting, it is performed an action of changing the effective period of the pulse output condition F _ua in accordance with the change of the phase control command theta _s as shown in FIG.

When the pulse width limited portion 8a became effective pulse output condition F _ua, ie the necessary and sufficient width to thyristor element 1u ignites when the phase angle signal theta _ua and the phase control command theta _s matches pulse P Outputs _ua .

(Problems to be Solved by the Invention) In the conventional phase control device described above, the pulses P _ua , P _va , P _wa , P _xa , and P _{x are generated} due to the failure of the phase control device 5a which is a normal system.
_When one or more of _ya and _Pza stop, there is a time delay before the failure detector 9 operates and the switching of the switching contact 10 is completed, so that the thyristor rectifier 1 cannot be controlled during that time. Therefore, there is a disadvantage that the DC power supplied to the load 3 fluctuates. Further, the failure detector 9 can detect the stop of the pulses P _ua , P _va , P _wa , P _xa , P _ya , and P _za , but for example, the phase angle signals θ _ua , θ _va due to the failure of the phase detection unit 6a. , θ _wa , θ _xa , θ _ya , θ _za show abnormal values, or the pulse output conditions F _ua , F
Detect errors in the phases of pulses P _ua , P _va , P _wa , P _xa , P _ya , and P _za that occur when _va , F _wa , F _xa , F _ya , and F _za indicate abnormal values. However, there is a disadvantage that control abnormality of the thyristor rectifier 1 cannot be prevented at this time.

SUMMARY OF THE INVENTION The present invention has been made in order to eliminate the above-mentioned conventional drawbacks, and has a highly reliable phase control device capable of continuously outputting a normal pulse to a thyristor rectifier even if the phase control device fails. The purpose is to provide.

[Configuration of the invention]

(Means for Solving the Problems) In order to achieve the object of the present invention, the present invention provides N (where N is an integer of 3 or more) phase control devices, and a comparison unit and a pulse unit of each phase control device. Between the width limiting units, N majority circuits that generate output signals based on the majority of the output conditions of the pulse outputs of the N comparison units are also multiplexed, and N pulses are provided. Each output signal of the N majority circuits triggers a pulse. The multiplexed pulse signals of the N pulse width limiting sections that output the signals are combined and output to each thyristor element of the thyristor device as a firing pulse, and the signals are multiplexed until the firing pulse is given to each thyristor element. .

(Operation) Thus, even if less than half of the N phase control devices fail, a pulse having a normal phase can be continuously output to the thyristor rectifier.

(Example) Hereinafter, an example of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows an embodiment of the present invention, in which the same components and operations as those in FIG. 6 are denoted by the same reference numerals, and the description thereof will be omitted. For simplicity of explanation, FIG. 1 shows the phase signals θ _ua , θ _va , θ _wa , θ _xa ,
θ _ya and θ _za are collectively expressed as θ _a, and the pulse output conditions F _ua , F _va , F _wa , F _xa , F _ya and F _za are _integrated into F _a
It represents a represents a pulse _{P ua, P va, P wa} , P xa, P ya, and P _a are summarized in one P _za.

6 differs from the conventional example of FIG. 6 in that the comparison units 7a, 7b, 7c and the pulse width limitation unit 8 of the phase control devices 11a, 11b, 11c are different.
a, 8b, and 8c, respectively, majority circuits 12a, 12b, and 12c are provided, and the phase control devices 11a, 11b, and 11c are tripled, the fault detector 9 and the switching contact 10 are removed, and the pulses P _a and P _b and _Pc are connected by a wired OR, and a pulse is given to the thyristor rectifier 1. Majority circuit 12a, 12b, 12c outputs each three pulses output condition Fa, Fb, Fc of the majority results G _a, G _b, the G _c pulse width limiting unit 8a, 8b, relative to 8c.

FIG. 2 is a detailed diagram of the majority circuits 12a, 12b and 12c.
It is composed of majority logic circuits 13u, 13v, 13w, 13x, 13y, and 13z each including a logical product 14a, 14b, 14c and a logical sum 15.

When any two or more of the pulse output conditions F _ua , F _ub , and F _uc output by the comparators 7a, 7b, and 7c are valid, the majority logic circuit 13u selects one of the logical products 14a, 14b, and 14c. Since the above holds, the logical sum 15 holds, and the majority decision result _Gua becomes valid.

FIG. 3 is a waveform diagram for explaining the operation of the phase control device 11a.
Only the signal for 1u is shown. In addition, the same parts as those in FIG.

In the figure, the period during which the pulse output conditions F _ua , F _ub , and F _uc show a normal value is t ₁ , the phase detection unit 6a or the comparison unit 7a fails, and the pulse output condition F _ua shows an abnormally valid value. The indicated period is indicated by t ₂ , and similarly, the period in which the pulse output condition F _ua abnormally indicates an invalid value is indicated by t ₃ . Majority result G _ua without being influenced by the pulse output condition F _ua showing the abnormal value, indicates a pulse output condition F _ub, same waveform and F _uc showing a normal value, and outputs a pulse P _ua normal phase be able to.

As described above, even if any one of the three pulse output conditions F _a , F _b , and F _c indicates an abnormal value, the majority decision results G _a , G _b , and G _c always maintain normal values. I understand. Also, the majority circuits 12a, 12b, 12c have the same pulse output conditions F _a , F _b , F
_{Since c} operates as an input, the phase control devices 11a and 11
b, 11c can output pulse P _a normal identical phase, P _b, the P _c to the thyristor rectifier 1.

According to the above-described embodiment, the phase control device is tripled and the pulses are output based on the majority decision of the three pulse output conditions. , A normal phase pulse can be continuously output to the thyristor rectifier.

FIG. 4 shows another embodiment of the present invention.
The same components and operations as in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted. The difference between FIG. 1 and FIG. 1 is that the control devices 4a, 4b, 4c together with the phase control devices 11a, 11b, 11c
c is also tripled. With this configuration, even if one of the control devices 4a, 4b, and 4c fails and one of the phase control commands θ _sa , θ _sb , and θ _sc indicates an abnormal value, the phase control device 11a , 11b, 11c are the pulse output conditions F
_The pulses P _a , P _b , and PE _c are output by majority decision of _a , F _b , and F _c , so that a pulse having a normal phase can be output to the thyristor rectifier 1.

FIG. 5 shows still another embodiment of the present invention.
Components having the same configuration and operation as those in the drawings are denoted by the same reference numerals, and description thereof will be omitted.

In the figure, the difference from the first figure, pulse P _a, P _b,
Rather than wired OR P _c , majority circuit 12a, 12
b, 12c, the pulses P _a , P _b , P
_The point that the majority result P of _c is supplied to the thyristor rectifier 1.

With this configuration, majority circuits 12a, 12b,
12c and the pulse width limited portion 8a, 8b, and failure any one of 8c, pulse P _a, P _b, even if any one of P _c indicates an abnormal value, normally to thyristor rectifier 1 It is possible to continuously output a pulse P having a proper phase.

It should be noted that the present invention is not limited to the embodiments and application examples described above.

For example, the majority circuits 12a, 12b, 12c are connected to the phase control devices 11a, 1
Although provided in 1b and 11c, respectively, the majority result may be supplied to the pulse width limiting circuits 8a, 8b and 8c by one majority circuit.

Further, after the pulse width limiters 8a, 8b, 8c, a pulse amplifier corresponding to the gate pulse capacity of the thyristor rectifier 1 is provided, and a failure detecting means is added to the inside or output of the phase control devices 11a, 11b, 11c. This does not change the gist of the present invention.

〔The invention's effect〕

As described above, according to the present invention, a pulse is output to the thyristor rectifier when the pulse output condition obtained by comparing the power supply voltage phase of the thyristor rectifier with the phase control command given from the control device becomes valid. Three or more phase control devices are provided, and the pulses are output based on the majority decision result of the pulse output conditions of each phase control device. Therefore, the load of the thyristor rectifier which has conventionally been caused by a single failure of the phase control device is provided. An extremely reliable phase control device capable of preventing fluctuations in power supply to the power supply and abnormal control can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a block diagram of a majority circuit, FIG. 3 is a waveform diagram for explaining the operation of a phase control device, and FIG. 4 is another embodiment of the present invention. Configuration diagram showing an example,
FIG. 5 is a block diagram showing an application example of the present invention, FIG. 6 is a block diagram showing a conventional phase control device, and FIG. 7 is a waveform diagram for explaining the operation of the conventional phase control device. 1. Thyristor rectifiers 11a, 11b, 11c Phase control devices 12a, 12b, 12c majority circuit

Claims (1)

(57) [Claims] 1. A control device for a thyristor device having a phase control device for outputting a firing pulse to each thyristor element of a thyristor device for controlling and rectifying an AC power supply to a direct current, wherein the phase control device comprises: (Where N is an integer of 3 or more) multiplexed phase detectors, and a pulse having a phase in accordance with a predetermined phase control command synchronized with the phase of the AC power supply detected by each of the phase detectors Multiplexed N comparators for outputting the output signals, N multiplexed majority circuits generating an output signal based on a majority result of the output conditions of the pulse outputs of the N comparators, A multiplexed N pulse width limiting unit that outputs a pulse signal having a predetermined width in response to an output signal, and the pulse signals of the N pulse width limiting units are coupled to each of the thyristor elements of the thyristor device. A control device for a thyristor device, comprising: a pulse coupling unit that outputs a firing pulse.