JP3480168B2 - Control method of voltage source inverter - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a voltage source inverter having a three-phase bridge connection configuration for switching circuits each having an anti-arc device and a diode connected in antiparallel.

[0002]

2. Description of the Related Art A conventional control method for this type of voltage source inverter is to convert the output voltage and frequency instructed at the time of starting the voltage source inverter into a pulse width modulated AC voltage synchronized with a carrier signal and output it. However, the output current of the voltage source inverter at this time is monitored, and when the output current exceeds a predetermined value, the starting of the voltage source inverter is stopped.

[0003]

According to the conventional control method for a voltage source inverter, even if there is a short-circuited portion in the load circuit of the voltage source inverter, for example, a low voltage commanded when the voltage source inverter is started, Low frequency (0.1-
At about 1.0 Hz), each of the first, second, and third switching series circuits comes to perform an on / off operation at the timing of the same phase as the carrier signal,
As a result, the current flowing through the load circuit is small, and it is difficult to detect the short-circuited portion of the load circuit even if the output current of the voltage source inverter is monitored.

An object of the present invention is to provide a voltage source inverter control method that solves the above problems.

[0005]

A first switching series circuit in which first and second switching circuits in which a self-extinguishing device and a diode are connected in anti-parallel are connected in series, and a first switching series circuit having the same configuration as the first switching circuit. A second switching series circuit in which third and fourth switching circuits are connected in series; and a third switching series circuit in which fifth and sixth switching circuits having the same configuration as the first switching circuit are connected in series. Both ends of each of the second and third switching series circuits and a DC power supply are connected in parallel with each other, and intermediate connection points of the first, second and third switching series circuits are respectively connected to the first phase, the second phase and the third phase. A phase-width output terminal is used to apply a pulse-width-modulated on / off signal to the self-extinguishing type devices of the first, second, and third switching series circuits, respectively. In a method of controlling a voltage source inverter, which generates a voltage at the output terminals of the first phase, the second phase, and the third phase, the first aspect of the present invention is predetermined when a start command is input to the voltage source inverter. A waveform voltage is output and the output current of the voltage source inverter at this time is monitored. If the output current does not exceed a predetermined value, normal operation is started, and when the output current exceeds a predetermined value, The startup of the voltage source inverter is stopped.

According to a second aspect of the present invention, in the first aspect, as the predetermined waveform, the waveform is provided with at least a first section and a second section from when the voltage source inverter is started, In section 1, the first, fourth, sixth
An ON signal is given to the self-turn-off device of each switching circuit, an OFF signal is given to the self-turn-off device of each of the second, third, and fifth switching circuits in the section, and the ON signal is given in the second section. An ON signal is given to the self-turn-off device of each of the first, third and sixth switching circuits, and an OFF signal is given to the self-turn-off device of each of the second, fourth and fifth switching circuits in the section. .

According to a third aspect of the present invention, in the first aspect, the predetermined waveform has at least a first section, a second section, and a third section from the start of the voltage source inverter. Is provided, an ON signal is given to the self-extinguishing type device of each of the first, fourth, and sixth switching circuits in the first section, and the second, third, and third sections of the section are provided.
An OFF signal is given to the self-turn-off device of each of the fifth switching circuits, and an ON signal is given to the self-turn-off device of each of the second, fourth, and sixth switching circuits in the second section, and the section is given. An OFF signal is given to the self-extinguishing type device of each of the first, third and fifth switching circuits, and in the third section, the first, third, sixth
An ON signal is given to the self-turn-off device of each switching circuit, and an OFF signal is given to the self-turn-off device of each of the second, fourth, and fifth switching circuits in the section.

According to a fourth aspect of the present invention, in the first aspect, the predetermined waveform has at least a first section, a second section, and a third section from the start of the voltage source inverter. And an ON signal is applied to the self-extinguishing type device of each of the first and fourth switching circuits in the first section, and the second, third, fifth, and fifth sections of the section are provided.
An OFF signal is given to the self-extinguishing type device of each of the sixth switching circuits, and in the second section, the third, sixth
An ON signal is given to each self-extinguishing device of each switching circuit, and an OFF signal is given to each self-extinguishing device of each of the first, second, fourth, and fifth switching circuits in the section, and the third signal is given. In the section, an ON signal is given to each self-extinguishing device of each of the second and fifth switching circuits, and OFF to each self-extinguishing device of each of the first, third, fourth and sixth switching circuits in the section. Give a signal.

A fifth aspect of the invention is applicable to the fourth aspect of the invention when the output current of the voltage inverter exceeds the predetermined value in any one of the first, second and third zones. The output terminal name based on the section is displayed externally. According to the present invention, when the voltage source inverter starts up, the voltage having the above-mentioned waveform such that current surely flows from the voltage source inverter to the load circuit is output for a predetermined period. Even when there is a short-circuited point, the short-circuited point can be detected by monitoring the output current of the voltage-source inverter at this time, and the voltage-source inverter can be stopped.

[0010]

1 is a flow chart of a voltage source inverter control method according to an embodiment of the present invention. In FIG. 1, when a start command is externally input to the voltage source inverter (step S1), output of a voltage having a predetermined waveform is started (step S2), and the output current of the voltage source inverter is monitored (step S1). S3), if this current exceeds a predetermined value (step S3, branch Y),
Stop the startup of this voltage source inverter (step S
4) This factor is displayed to the outside (step S5).

In step S3, if the output current of the voltage source inverter has not reached a predetermined value (step S3).
3, branch N), it is checked whether or not the output period of the waveform generated in step S2 has ended (step S6). If not completed (step S6, branch N), the process returns to step S2 and ends. If so (step S6, branch Y), normal operation is performed based on the output voltage and frequency commanded from the outside (step S7).

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 is a main circuit configuration diagram of a voltage type inverter having a three-phase bridge connection of switching circuits in which a self-arc-extinguishing type device and a diode are connected in antiparallel. Is a main circuit of a voltage type inverter, 3 is a load circuit, and the main circuit 2 is an IGBT 11-16 as a self-extinguishing type device and a diode 21-2.
6 and 6.

FIG. 3 shows a first embodiment of the present invention,
The IGBT 1 of the main circuit 2 of the voltage source inverter shown in FIG.
It is a wave form diagram of the ON / OFF signal to 1-16. In FIG. 3, a section from the start time T ₀ to the time T ₂ of the voltage source inverter shown in FIG. 2 is set, and an ON signal is given to each of the IGBTs 11, 14 and 16 in the section from the time T _{0 to} T ₁ . Further, an OFF signal is given to the remaining IGBTs, and the time T ₁
In the interval from T ₂ to T _2, an ON signal is given to each of the IGBTs 11, 13 and 16 and an OFF signal is given to the remaining IGBTs. After time T ₂ , waveforms based on the output voltage and frequency commanded at the time of conventional start-up Output AC voltage.

That is, in the section from time T _{0 to} T ₁ , by monitoring the output current of the voltage-source inverter in this section, the first-phase output terminal of the voltage-source inverter of the load circuit 3-2
It is possible to detect a short circuit between the phase output terminals or between the first phase output terminal and the third phase output terminal. Further, in the section from time T _{1 to} T ₂ , by monitoring the output current of the voltage source inverter in this section, between the first phase output terminal and the third phase output terminal of the voltage source inverter of the load circuit 3 or the second phase. It is possible to detect a short circuit between the output terminal and the third phase output terminal.

Incidentally, in FIG. 3, the object of the present invention can be achieved even if the section of time T _{0 to} T _{1 and} the section of time T _{1 to} T ₂ are exchanged, and the time T ₂ and normal operation start. In between, for example, there may be a rest period in which all the IGBTs 11 to 16 are provided with an off signal. FIG. 4 shows a second embodiment of the present invention and is a waveform diagram of ON / OFF signals to the IGBTs 11 to 16 of the main circuit 2 of the voltage type inverter shown in FIG.

In FIG. 4, the voltage source IN shown in FIG.
When the barter starts up T₀Than time T₃Set the section up to
Time T₀~ T₁In the section of, IGBT11,14,16
Give an ON signal to each and turn off the rest of the IGBTs
Give a signal, time T₁~ T₂IGBT12,
An ON signal is given to each of 14 and 16 and the remaining IG
An off signal is given to BT, and the time T₂~ T₃In the section of
An ON signal is given to each of GBTs 11, 13, 16 and
OFF signal is applied to the remaining IGBTs at time T ₃Or later
Is based on the output voltage and frequency commanded during conventional startup.
Outputs a rectangular waveform AC voltage.

That is, in the section from time T _{0 to} T ₁ , by monitoring the output current of the voltage-source inverter in this section, the first-phase output terminal of the voltage-source inverter of the load circuit 3-2
It is possible to detect a short circuit between the phase output terminals or between the first phase output terminal and the third phase output terminal. Further, in the section from time T _{1 to} T _2, the current flowing in the load circuit 3 is stopped so that the current flowing in the section from time T _{0 to} T ₁ is prevented from becoming excessive.

Further, in the section from time T _{2 to} T ₃ , by monitoring the output current of the voltage-source inverter in this section, the first-phase output terminal-third of the voltage-source inverter of the load circuit 3
It is possible to detect a short circuit between the phase output terminals or between the second phase output terminal and the third phase output terminal. In FIG. 4, time T
The object of the present invention can be achieved even if the section of _{0 to} T _{1 and} the section of time T _{2 to} T ₃ are switched, and, for example, all of the IGBTs 11 to 16 are turned off between the time T ₃ and the start of normal operation. There may be a rest period to signal.

FIG. 5 shows a third embodiment of the present invention,
The IGBT 1 of the main circuit 2 of the voltage source inverter shown in FIG.
It is a wave form diagram of the ON / OFF signal to 1-16. In FIG. 5, a section from the start time T ₀ of the voltage source inverter shown in FIG. 2 to the time T ₃ is set, and an ON signal is given to each of the IGBTs 11 and 14 in the section from the time T _{0 to} T ₁ and the remaining OFF signal is applied to the IGBTs of time points T _{1 to} T ₂
In the section of, the ON signals are given to the IGBTs 13 and 16 respectively, and the OFF signals are given to the remaining IGBTs at time T ₂
Giving an ON signal to IGBT12,15 respectively in through T ₃ sections, and the remaining IGBT give off signal, the time T ₃ after the output voltage command to the conventional startup, alternating-current voltage waveform based on the frequency Is output.

That is, in the section from time T _{0 to} T ₁ , by monitoring the output current of the voltage-source inverter in this section, between the first-phase output terminal and the second-phase output terminal of the voltage-source inverter of the load circuit 3. Can detect short-circuited points. Also, at time T ₁
The through T ₂ of the section, the second phase output terminal of the voltage source inverter of the load circuit 3 by monitoring the output current of the voltage source inverter of this leg - can be detected in the short-circuited portion between the third phase output terminal. Further, in the interval time T ₂ through T _3, this section of the voltage source inverter output current of the first phase output terminal of the voltage source inverter of the load circuit 3 by monitoring - short-circuit portion between the third phase output Output terminal Since it is possible to detect the short circuit, it is possible to identify the short-circuited portion, and it is easy to display this to the outside.

In FIG. 5, the object of the present invention can be achieved even if the order of the section of time T _{0 to} T ₁ , the section of time T _{1 to} T _{2 and} the section of time T _{2 to} T ₃ are interchanged,
Also, between time T _{0 and} T ₁ and time T _{1 and} T ₂ , time T ₁
Between T ₂ and times T _{2 and} T ₃ and between the time T ₃ and the start of normal operation, for example, there may be a rest period in which an off signal is given to all the IGBTs 11 to 16.

[0022]

According to the present invention, the voltage of the above-mentioned waveform that ensures that current flows from the voltage source inverter to the load circuit when the voltage source inverter is started up is applied for a predetermined period (about 50 μsec to 70 μsec per section). ) By outputting, the short-circuited part of the load circuit can be reliably detected, and the protection function of the device can be improved.

[Brief description of drawings]

FIG. 1 is a flowchart of a voltage source inverter control method according to an embodiment of the present invention.

[Fig. 2] Main circuit configuration diagram of voltage source inverter

FIG. 3 is a waveform diagram of the voltage type inverter showing the first embodiment of the present invention.

FIG. 4 is a waveform diagram of a voltage type inverter showing a second embodiment of the present invention.

FIG. 5 is a waveform diagram of a voltage source inverter showing a third embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... DC power supply, 2 ... Main circuit of voltage type inverter, 3 ... Load circuit, 11-16 ... IGBT, 21-26 ... Diode.

Continuation of the front page (56) Reference JP-A-6-66901 (JP, A) Actual development Sho 63-77488 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) H02M 7 / 48 H02H 7/122

Claims (5)

(57) [Claims] 1. A first switching series circuit in which first and second switching circuits in which a self-extinguishing type device and a diode are connected in anti-parallel are connected in series, and third and fourth circuits having the same configuration as the first switching circuit. A second switching series circuit in which switching circuits are connected in series; and a third switching series circuit in which fifth and sixth switching circuits having the same configuration as the first switching circuit are connected in series, the first, second, and second switching circuits. Both ends of each of the three switching series circuits and a DC power source are connected in parallel to each other, and the intermediate connection points of the first, second, and third switching series circuits are output terminals of the first phase, the second phase, and the third phase. And applying a pulse-width modulated on / off signal to the self-extinguishing type devices of the first, second, and third switching series circuits to apply a three-phase alternating voltage to the first , The second phase, the third
A method for controlling a voltage source inverter that generates the output terminal of the phase, the start command to the voltage-source inverter is input, the output voltage of a predetermined waveform output current of the voltage source inverter for the time monitoring The output current exceeds a specified value
If not, the normal operation is started, and when the output current exceeds a predetermined value, the start-up of the voltage source inverter is stopped, and the method for controlling the voltage source inverter. 2. The voltage source inverter control method according to claim 1, wherein the predetermined waveform is provided with at least a first section and a second section after the voltage source inverter is started. In the first section, an ON signal is given to the self-turn-off device of each of the first, fourth and sixth switching circuits,
An OFF signal is given to the self-extinguishing type device of each of the second, third, and fifth switching circuits in the section, and the self-extinguishing of each of the first, third, and sixth switching circuits in the second section. The ON signal to the shaped device,
A control method of a voltage type inverter, wherein an OFF signal is given to the self-turn-off device of each of the second, fourth, and fifth switching circuits in the section. 3. The voltage source inverter control method according to claim 1, wherein the predetermined waveform has at least a first section, a second section, and a third section after the voltage source inverter is started. And an ON signal is applied to the self-extinguishing type device of each of the first, fourth and sixth switching circuits in the first section,
An OFF signal is given to the self-extinguishing type device of each of the second, third, and fifth switching circuits in the section, and a self-extinguishing of each of the second, fourth, and sixth switching circuits in the second section. The ON signal to the shaped device,
An OFF signal is given to each self-extinguishing device of each of the first, third, and fifth switching circuits in the section, and a self-extinguishing of each of the first, third, and sixth switching circuits in the third section. The ON signal to the shaped device,
A control method of a voltage type inverter, wherein an OFF signal is given to the self-turn-off device of each of the second, fourth, and fifth switching circuits in the section. 4. The control method for a voltage source inverter according to claim 1, wherein the predetermined waveform has at least a first section, a second section, and a third section from the time of starting the voltage source inverter. And an ON signal is given to the self-extinguishing type device of each of the first and fourth switching circuits in the first section, and the second, third, fifth and sixth switching circuits in the section are provided. An OFF signal is given to each self-extinguishing device, an ON signal is given to each self-extinguishing device of each of the third and sixth switching circuits in the second section, and the first and second sections in the section are given. , An OFF signal is given to the self-turn-off device of each of the fourth and fifth switching circuits, and an ON signal is given to the self-turn-off device of each of the second and fifth switching circuits in the third section, A method of controlling a voltage type inverter, characterized in that an OFF signal is applied to the self-turn-off device of each of the first, third, fourth and sixth switching circuits in the section. 5. The voltage source inverter control method according to claim 4, wherein the output current of the voltage inverter exceeds the predetermined value in any one of the first, second, and third sections. A method of controlling a voltage source inverter, wherein the output terminal name based on a corresponding section is displayed outside.