JP3425360B2 - Test method for self-excited converter - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for testing a self-excited converter.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram of a test circuit for a conventional self-excited converter. A rectifier 2 for supplying DC power to the self-excited converter 1 is connected to the DC side of the self-excited converter 1, and a reactor 3 as a load is connected to the AC side of the self-excited converter 1.

In the test circuit of FIG. 4, the rated DC voltage is maintained while the DC power for the loss of the self-excited converter 1 and the reactor 3 is supplied from the rectifier 2. The self-excited converter 1 is operated in the rated operating state, that is, the rated frequency, rated current, and rated output voltage. For the reactor 3, an inductance through which a rated current flows at a rated output voltage is selected.

FIG. 5 is a configuration diagram of one phase of the self-excited converter 1. A diode 5 is connected in anti-parallel to the switching element 4.
, And a snubber circuit composed of a diode, a capacitor, and a resistor is connected in parallel.

FIG. 6 is a diagram for explaining the operation of a conventional test circuit. (A) shows a triangular wave carrier and voltage reference, (b)
Indicates the output line voltage, (c) indicates the current flowing through the reactor 3, and (d) indicates the current flowing through the switching element.

The switching element 4-1 is turned on / off by comparing a triangular wave carrier with a sine wave which is a voltage reference value, and is turned on when the voltage reference value is larger than the carrier wave. 1st in the case of a self-excited converter with a single-phase bridge connection
The second phase is provided with a voltage reference value delayed by 180 ° with respect to the phase, and switching of the switching element is determined.

In FIG. 6, (d) is the current flowing through the switching element 4-1 and the diode 5-1. The positive side is the current flowing through the switching element 4-1 and the negative side is the current flowing through the diode 5-1. is there.

In this test circuit, since the reactor 3 is used as a load, the load power factor is zero and the current is delayed by 90 ° from the voltage. Therefore, 1/2 of the current flows to the switching element 4-1, and the remaining 1/2 is the diode 5-1.
Flow to.

According to this method, the self-excited converter can be operated in a rated state with a small amount of electric power, and therefore it is generally used. In particular, in a large-capacity self-excited converter, it is not possible to connect to a power supply system or prepare a resistive load having a rated capacity, so that it is widely used as a test method by manufacturers.

[0010]

However, the conventional test circuit has the following problems. Originally, the current flowing through the switching element 4-1 when the self-excited converter 1 outputs active power is as shown in FIG. 7. That is, the current waveform in the conventional test method is obviously easier.

[0011] For this reason, in the conventional test methods can not be said has given the actual operation and equivalent responsibilities. Moreover, in order to adjust the voltage reference value to the actual operation, the reactor 3
It was uneconomical to prepare the inductance value for each product.

Therefore, the present invention eliminates the above-mentioned problems, and provides a test method capable of giving a duty equivalent to actual operation to a self-excited converter with a test circuit equivalent to a conventional one. With the goal.

[0013]

In order to achieve the above object, in the method for testing a self-excited converter according to claim 1 of the present invention, any one phase of a single-phase inverter is switched in a predetermined operating state. And set the remaining one phase to the first
The phase and amplitude are adjusted so that the phase of the current is −180 ° to 180 ° with respect to the voltage of the phase. Thus, except for the case where the current phase is 90 ° with respect to the voltage of the first phase, the same state as that of outputting active power can be obtained from the viewpoint of the switching element of the first phase of the single-phase inverter. By changing the phase and amplitude of the second phase, the same state as the actual operating state can be created, and the switching element can be given a duty equivalent to the actual operating state. Moreover, since the active power is not actually output, the power used for the test is only the loss of the converter and the loss of the reactor as in the conventional case, and a large amount of power is not required. Furthermore, by adjusting the second phase, it is possible to adjust the inductance value of the reactance to any required current value, and it is not necessary to adjust the inductance for each product. Further, since the rated current can be adjusted even if the inductance value is small, the inductance may be small, and the test equipment can be downsized.

In the method for testing a self-excited converter according to claim 2 of the present invention, any one phase of the three-phase inverter is set to a switching state in a predetermined operating state, and one of the remaining two phases is set to the above-mentioned one. The phase of the current is -180 with respect to the voltage of the first phase.
Adjust the phase and amplitude so that the angle is between 180 ° and 180 °. As a result, except for the case where the current phase is 90 ° with respect to the voltage of the first phase, the same state as the output of active power can be obtained from the viewpoint of the switching element of the first phase of the three-phase inverter. Yes, by changing the phase and amplitude of the second phase,
The same state as the actual operating state can be created, and the switching element can be given a responsibility equivalent to the actual operating state. Moreover, since the active power is not actually output, the power used for the test is only the loss of the converter and the loss of the reactor as in the conventional case, and a large amount of power is not required.
Furthermore, by adjusting the second phase, it is possible to adjust the inductance value of the reactance to any required current value, and it is not necessary to adjust the inductance for each product. Further, since the rated current can be adjusted even if the inductance value is small, the inductance may be small, and the test equipment can be downsized.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an operation explanatory diagram of the first embodiment of the present invention. (A) is the carrier wave of the triangular wave and the current reference values of the first phase and the second phase, (b) is the output line voltage obtained from the voltage reference values of the first phase and the second phase, (c) Is a current flowing through the reactor 3. Figure 2
[Fig. 3] is a vector diagram showing an output voltage and a current.

In this embodiment, the voltage reference value of the first phase is set to the rated operation state, and the voltage reference value of the second phase is set to the phase of the output line voltage with respect to the voltage reference value of the first phase. Is 90 °
Set so that the phase is advanced.

When the operation is performed with such a setting, the phase of the current flowing through the reactor 3 is 90 with respect to the output line voltage.
Since the phase is delayed, the phase of the current flowing in the reactor 3 becomes the same phase as the voltage reference value of the first phase. this is,
From the viewpoint of the first-phase switching element, the state becomes the same as the state in which active power is output, and the current waveform shown in FIG. 7 flows through the first-phase switching element.

Further, by changing the phase and amplitude of the second phase as shown in FIG. 3, the phase of current can be freely changed with respect to the voltage of the first phase. As described above, by adjusting the amplitude and phase of the second phase, the phase of the current can be freely adjusted with respect to the voltage of the first phase, and the switching element 4 of the first phase has a duty equivalent to that of the actual operation. It is possible to give
Also, since the self-excited converter does not generate active power,
The power supplied by the rectifier 2 is only the loss of the converter and the loss of the reactor as in the conventional case, and large power is not required.

Further, the reactance 3 is adjusted by adjusting the second phase.
Any inductance value can be adjusted to a required current value, and it is not necessary to adjust the inductance for each product. Further, since the rated current can be adjusted even if the inductance value is small, the inductance 3 may be small, and the test equipment can be downsized.

Next, a case where the present invention is applied to a three-phase bridge-connected self-exciting converter will be described. The basic concept of the self-excited converter of the three-phase bridge structure is the same as that of the self-excited converter of the single-phase bridge structure described above, and the difference is the handling of the third phase.

By setting the voltage reference value of the first phase to the rated operation state and adjusting the amplitude and phase of the voltage reference value of the second phase, the current phase is adjusted with respect to the voltage of the first phase. To do.
Then, the remaining third phase may be brought into a stopped state or operated with the same voltage reference as the second phase.

As a result, the same effect as that of the self-exciting converter having the above-mentioned single-phase bridge structure can be obtained, and it is possible to perform a test with the same power as the conventional one while giving the switching element a duty equivalent to the actual operating state. It is possible to provide a test method that is economical, highly reliable, and has a small reactor.

In the above description, the connection method of the self-excited converter is described as a single-phase bridge or a three-phase bridge, but the same effect can be obtained by any connection method regardless of the converter connection method. For example, a multi-level inverter system may be used.
Further, the phase and amplitude of the second phase may be manually adjusted, or may be automatically adjusted by the current control system.

[0024]

As described in detail above, according to the present invention,
It is possible to perform a test in which the switching device is given a duty equivalent to the actual operating state in a small-capacity test facility, and it is possible to provide an economical and highly reliable test method for a self-excited converter.

[Brief description of drawings]

FIG. 1 is an operation explanatory diagram of the first embodiment of the present invention.

FIG. 2 is a vector diagram showing output voltage and current.

FIG. 3 is a vector diagram showing output voltage and current.

FIG. 4 is a configuration diagram of a test circuit of a self-excited converter.

FIG. 5 is a configuration diagram of one phase of a self-excited converter.

FIG. 6 is an operation explanatory diagram of a conventional test circuit.

FIG. 7 is a waveform of a current flowing through the switching element when the self-exciting converter outputs active power.

[Explanation of symbols]

1-Self-excited converter 2 rectifier 3 ... Reactor 4 ... Switching element 5 ... Diode

Claims (2)

(57) [Claims] 1. A test method for a self-excited converter in which a reactor is connected to a load side of a single-phase inverter, wherein any one phase of the single-phase inverter is set to a switching state in a predetermined operating state, and the remaining 1 phase is set. A test method for a self-excited converter, wherein the phase and the amplitude are adjusted so that the phase of the current is −180 ° to 180 ° with respect to the voltage of the first phase. 2. A test method for a self-excited converter in which a reactor is connected to a load side of a three-phase inverter, wherein any one phase of the three-phase inverter is set to a switching state in a predetermined operating state, and the remaining two phases are set. One of the phases is the first
A test method for a self-excited converter, characterized in that the phase and amplitude are adjusted so that the current phase is -180 ° to 180 ° with respect to the phase voltage.