JPS6350954B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power conversion device with a forward converter consisting of a controllable electric valve, such as a thyristor.

For convenience of explanation, an inverter device will be described below as an example of a power conversion device.

For example, a control element (hereinafter referred to as a controllable electric valve) that can control the switching operation, such as a thyristor, is used as a forward converter, and the ignition phase of this controllable electric valve is controlled to control the DC voltage that is its output. An inverter device is known. This type of inverter device usually prepares a reference signal for determining the firing phase that is synchronized with the voltage applied to each controllable electric valve in the forward converter, and sets a predetermined firing phase according to this reference signal. It is controlled to fire at the phase of .

FIG. 1 shows a general circuit configuration diagram of a conventional inverter device. In the figure, V _R , V _S , V _T represent the inverter input power supply voltage, and the phase rotation direction is V _R , V _S ,
The order is V _T.

In this conventional inverter device 50, voltages V _R , V _S , and V _T are supplied to three input terminals S1, S2, and S3, respectively. In this example, the forward converter 1 uses a three-phase mixing bridge whose upper arm is constituted by a controllable electric valve. TH1, TH2, and TH3 are controllable electric valves, D1, D2, and D3 are diodes, 10 is an inverter, 20 is a synchronous power supply unit that takes out a reference signal for determining the firing phase, and 30 is a synchronous power supply unit 20.
This is an ignition means that outputs an ignition signal based on the output signal and voltage command.

FIG. 2 shows a circuit diagram of the synchronous power supply unit and ignition means shown in FIG. 1. In the same figure, PT1, PT2, PT3
are voltage transformers that detect line voltages V _RT , V _SR , and V _TS , respectively; F1, F2, and F3 are waveform conversion circuits that convert sine waves into rectangular shapes; I1, I2, and I3 are integrators; C1 and C2. , C3 are comparators, and Vc is a voltage command corresponding to the forward converter output voltage. Note that the line voltage V _RT represents the potential of the voltage _VR with respect to the voltage _VT , and the same notation is used for the line voltages V _SR and V _TS .

In this example, inverter input terminals S1, S2,
Since the input power supply voltages V _R , V _S , and V _T are connected to S3, respectively, the voltage transformers PT1, PT2, and PT3
The outputs of are V _1-3 = V _RT , V _2-1 = V _SR , V _3-2 = V _TS
A voltage proportional to is output. Therefore, the outputs F10, F20, F3 of the waveform conversion circuits F1, F2, F3
0 is a rectangular wave synchronized with the positive half cycle period of the line voltages V _RT , V _SR , and V _TR . If this rectangular wave is input to integrators I1, I2, and I3, and the rectangular wave is integrated only during the period when it is at the H level, and when the integrators I1, I2, and I3 are reset when switching to the L level, a signal having a sawtooth waveform is generated. is obtained. FIG. 3 shows the output signal I10 of the integrator I1. This output signal I10 is compared with the voltage command Vc, and when the voltage of the signal I10 is output only in the section where it is higher than Vc, the ignition signal P1 of the controllable electric valve TH1 is obtained.

This also applies to the output signals I20, I30 and the ignition signals P2, P3, and the controllable electric valves TH1, TH1, which have the ignition phase indicated by α in FIG.
Firing signals P1, P2, and P3 of TH2 and TH3 are obtained. Therefore, by controlling the voltage command Vc, the ignition phase α can be controlled, thereby controlling the DC voltage that is the forward converter output. The inverter device 50 operates by converting the DC voltage, which can be controlled by the voltage command Vc, into an AC output using the inverter 10.

Here, the connections between the input terminals S1, S2, S3 and the input power supply voltages V _R , V _S , V _T are as follows:
2. Seen from S3, the input voltage phase is G1, S2, S
There are two types of connection states: a connection state that progresses in the order of S1, S3, and S2 (hereinafter referred to as a negative-phase rotation connection state).
Hereinafter, the circuit configuration remains as is, and the input terminals S1 and S
2. Consider an anti-phase rotation connection state in which voltages V _R , V _T , and V _S are connected to S3.

In this case, terminals S1, S2, and S3 have V _R , V _T ,
Since V _S is connected, the inputs V _1-3 of voltage transformers PT1, PT2, and PT3 that detect the line voltage are
V _2-1 and V _3-2 are respectively V _1-3 = V _RS , V _2-1 = V _TR ,
V _3-2 = V _ST will be input, so Figure 6B
As shown, the controllable electric valves TH1, TH2, TH
The synchronous power supply signal V _RT required to fire 3,
Signals that are 60 degrees ahead in phase compared to V _SR and V _TS are picked up. As a result, the outputs F10, F20, F3 of the waveform conversion circuits F1, F2, F3
0, outputs I10, I2 of integrators I1, I2, I3
0, I30 also leads by 60 degrees compared to the required signal, and the signal obtained by comparison with the voltage command Vc also leads by 60 degrees compared to the required phase.

Therefore, if this continues, the controllable electric valve TH
1, TH2, and TH3, a region where ignition is impossible occurs due to the reverse voltage, or the ignition pulse is interrupted in a region where the ignition phase is smaller than 60 degrees, so the controllable electric valves TH1, TH2, and TH3 A region where the ignition phase is small is uncontrollable, resulting in a region where the output DC voltage of the forward converter is uncontrollable.

In this way, the controllable electric valves TH1, TH2,
In the inverter device 50 having the forward converter 1 configured with TH3, the input power is connected to the input terminal S.
For example, if a circuit that outputs an ignition signal is configured for S1, S2, and S3 on the assumption that they will be connected for positive phase rotation, if they are connected for negative phase rotation, problems will occur in the forward converter operation. As a result, there were drawbacks such as the inverter not operating properly.

The present invention has been made in view of the above-mentioned conventional circumstances, and its purpose is to provide a power converter equipped with a forward converter consisting of a controllable electric valve that operates normally regardless of the connection state of the input power source. It is in.

In order to achieve this object, the present invention includes a phase rotation direction detection means for detecting the phase rotation direction of an input power source connected to an input terminal, and a phase rotation direction detecting means that detects the phase rotation direction based on the output of this phase rotation direction detection means. ignition means is provided for selecting a reference signal for determining the ignition phase of each controllable electric valve of the forward converter and outputting a predetermined ignition signal so that the controllable electric valve of the forward converter operates normally without any interference; Depending on whether the switching point from positive to negative or from negative to positive for one phase or line voltage of the input power supply is in the positive half cycle or negative half cycle of the other phase or line voltage, detects whether the connection to the input terminal is a normal-phase rotation connection or a reverse-phase rotation connection, and depending on the detection signal, outputs a voltage pulse corresponding to each phase of the input power supply that is connected to a reverse-phase rotation connection. The gist of this invention is to have a configuration in which the output is switched and outputted so that

An embodiment of the present invention will be described below with reference to FIGS. 4 to 6A and 6B.

FIG. 4 shows a circuit configuration diagram of an inverter device according to an embodiment of the present invention, in which the same components as in FIG. 1 are given the same reference numerals.

The inverter device 100 shown in FIG. 4 includes controllable electric valves TH1, TH2, TH3, diodes D
1, D2, and D3 is different from the conventional inverter device 50.
, and further input terminals S1, S2, S3
It is also the same as the inverter device 50 in that the input power supply voltage supplied to the synchronous power supply unit 20 is output as a rectangular wave synchronized to the positive side of the line voltages V _1-3 , V _2-1 , and V _3-2 . .

Reference numeral 40 denotes a phase rotation direction detecting means constituting a main part of the present invention, which is interposed between the synchronous power supply section 20 and the ignition means 30. This phase rotation direction detection means 4
0 is a positive phase rotation connection state in which the input power supply connected to input terminals S1, S2, S3 advances in the order of terminals S1, S2, S3, or S1, S3,
The controllable electric valve TH
1, TH2, TH3 synchronous power outputs F10, F20, F3, which will be described later, serve as the reference for determining the ignition phase of TH3.
Send 0 or 20, 30, 10.

The ignition means 30 transmits ignition signals P1, P2, and P3 determined by the voltage command Vc to controllable electric valves, respectively.
As a result, the forward converter 1 outputs a DC voltage based on the voltage command Vc, which is converted into an AC voltage by the inverse converter 10.

Here, in the embodiment shown in FIG. 5, the phase rotation direction detection means 40 includes a waveform conversion circuit F1,
A phase rotation direction detector 41 is provided to detect the phase rotation direction based on outputs F10, F20, and F30 of F2 and F3. In this embodiment, the phase rotation direction detector 41 detects whether there is a switching point from negative to positive line voltage V _2-1 during the positive half cycle period of line voltage V _1-3 or vice versa. Detects whether a switching point from positive to negative exists and determines whether the connection is a positive phase rotation connection or a negative phase rotation connection.

That is, for example, in a positive phase rotational connection state,
V _1-3 = V _RT , V _2-1 = V _SR , V _3-2 = V _TS ,
Therefore, the line voltage advances in the order of V _1-3 , V _2-1 , and V _3-2 , so as shown in FIG. 6A, for example, V _1-3
There is a switching point from negative to positive for V _2-1 and a switching point from positive to negative for V _3-2 during the positive half cycle of .

Also, on the contrary, V _1-3 = V _RS , V _3-2 = V _ST ,
In the reverse phase rotation connection state where V _2-1 = V _TR ,
Since the line voltage advances in the order of V _1-3 , V _3-2 , and V _2-1 , for example, during the positive half cycle of V _1-3 , V _2-1 increases as shown in FIG. 6B. switching point from positive to negative,
There is a switching point from negative to positive V _3-2 .

In this way, by detecting the presence or absence of the polarity switching point of V _2-1 or V _3-2 that exists during the positive half cycle of V _1-3 , it is possible to determine whether it is a positive phase rotation connection or a negative phase rotation connection. It is possible.

In reality, during the H level period of the synchronous power output F10, there is a switching point where the level of the synchronous power output F20 changes from L to H, and if it is determined that the connection is positive phase rotation, the phase rotation direction detector 41 outputs an H level signal to the output terminal 41a and an L level signal to the output terminal 41b. As a result, each AND gate 42a in the phase rotation direction detection means 40 opens, and the synchronous power outputs F10 and F2 are output via the OR gate 42.
0, F30 are output to integrators I1, I2, I3. Further, when the synchronous power supply output F20 switches from H to L, it is determined that the connection is in reverse phase rotation, and the phase rotation direction detector 41 outputs an L level signal to the output terminal 41a and an L level signal to the output terminal 41b. Outputs an H level signal. As a result, each AND gate 42b in the phase rotation direction detection means 40 opens, and the OR gate 42b opens.
The synchronous power supply outputs 20, 30, 10 are outputted to integrators I1, I2, I3 via. Note that the synchronous power outputs 10, 20, and 30 are synchronous power outputs F whose polarities are inverted by the inverter 43, respectively.
10, F20, F30.

Next, a reference signal for determining the firing phases of the controllable electric valves TH1, TH2, and TH3 will be explained. This reference signal is applied to input terminals S1, S2, S3
and the power supply voltages V _R , V _S , and _VT must be either V _RT , V _SR , or V _TS , respectively, regardless of the connection status of V R , V S , and VT . Therefore, in the positive phase rotation connection state, the input line voltage of the synchronous power supply section 20 becomes the reference as it is,
Therefore, the waveform conversion circuit output F to the ignition means 30 is
10, F20, and F30 are input as they are.

Therefore, the controllable electric valves TH1, TH2, TH3
A signal synchronized with V _RT , V _SR , and V _TS corresponds to the reference signal, and by comparing the sawtooth outputs I10, I20, and I30, which are the outputs of the integrators I1, I2, and I3, with the voltage command Vc, Output I10, I20,
Intersection of I30 and Vc or I10, I20, I3
During the period in which the level of 0 is greater than Vc, the ignition signal P
1, P2, P3 are controllable electric valves TH1, TH2,
The signal is output to TH3, and the inverter device 100 operates normally.

Conversely, in the reverse phase rotation connection state, input terminals S1, S2, and S3 have V _R , V T , and V _T , respectively.
Since V _S is being supplied, the input line voltages V _1-3 , V _2-1 , V _3-2 to the synchronous power supply unit 20 are compared with V _RT , V _TS , V _SR which should be the reference signals. 60 in electrical angle
They have an advanced relationship. Therefore, V _1-3 , V _2-1 ,
In order to obtain the same effect as when V _3-2 is delayed by 60 degrees in calculation, in this embodiment, signals synchronized with V _RT , V _TS , and V _SR are changed to V _2-1 , V _3-2 , and V _{1- ,} respectively. ₃ polarity inversion signal
It is configured to be made with V _2-1 , _3-2 , and _1-3 . In terms of the output states of the waveform conversion circuits F1, F2, F3, this means the outputs F10, F20, F of the synchronous power supply section 20.
Inverted output 1 obtained by inverting the polarity of 30
This is a state in which 0, 20, and 30 are output.

Therefore, the controllable electric valves TH1, TH2, TH3
Again, _2-1 = V _RT , _3-2 = V _TS , _1-3 =
A signal synchronized with V _SR corresponds to the reference signal.
As a result, the controllable electric valves TH1, TH2, and TH3 can be fired at the correct firing phase even in the reverse phase rotation connection state, so that the forward converter 1 can operate correctly, and by extension, the inverter device 100 can also operate normally. I can do it.

In the above embodiment, the upper arm is a three-phase full-wave mixing bridge (forward converter) consisting of a controllable electric valve.
Taking as an example the inverter device 100 equipped with
In addition to this, the inverter device may be a 3-phase full-wave mixed bridge whose lower arm is composed of controllable electric valves, a 3-phase full-wave pure bridge whose lower arm is entirely composed of controllable electric valves, or a more multi-phase bridge. It may also be configured using a pure bridge.

Further, as in the embodiment, the phase rotation direction detecting means 40 detects whether the switching point from positive to negative or from negative to positive of one voltage seen between the input terminals is in the positive half cycle or the negative half cycle of the other line voltage. Since the phase rotation direction of the input power source as seen from the input terminal is detected by detecting whether the phase rotation direction is present, the phase rotation direction can be detected extremely easily. This can be done in a similar manner from the phase voltages of the input power supply connected to the input terminals. Especially when the input power source is a three-phase AC power source as in this embodiment, it is only necessary to compare the time before and after the switching point between any two phase voltages or between two line voltages. This has the advantage of simplifying the circuit configuration.

In the above embodiment, an inverter device was described as an example of a power converter, but it is clear that the present invention can be widely applied to power converters having a forward converter based on its gist.

As explained above, according to the power conversion device of the present invention, the phase rotation direction detection means for detecting the phase rotation direction of the input power source connected to the input terminal of the forward converter is provided, and the output of the phase rotation direction detection means is ignition means for igniting the forward converter at a predetermined ignition phase based on the ignition phase; Depending on whether the point is in the positive or negative half cycle of the other phase or line voltage,
Detects whether the connection of the input power supply to the input terminal is a normal phase rotation connection or a reverse phase rotation connection, and according to the detection signal, normal phase rotation is applied to the voltage pulses corresponding to each phase of the input power supply that is in the reverse phase rotation connection state. Since the configuration is such that the input power supply is switched to output when connected, accurate ignition is possible in either state, whether the input power supply is connected with normal phase rotation or reverse phase rotation. Therefore, for example, if the input power supply is connected to the input terminal in reverse phase rotation, as in a conventional device that assumes that it is connected in positive phase rotation, contrary to this assumption, ignition will occur. There is no inconvenience such as a region in which the forward converter made of a controllable electric valve cannot be controlled due to a phase shift, and this has the effect that accurate ignition phase control is always possible.

[Brief explanation of drawings]

Figure 1 is a general circuit diagram of a conventional device having a forward converter consisting of a controllable electric valve, and Figure 2 is a diagram of the
Circuit diagram of the synchronous power supply unit and ignition means shown in Figure 3.
The figure is a signal waveform diagram for explaining the operation of each part of the device shown in Figure 1, Figure 4 is a circuit configuration diagram when applied to an inverter device as an embodiment of the power conversion device of the present invention, The figure is a circuit diagram of one embodiment of the phase rotation direction detection means, and FIGS. 6A and 6B are signal waveform diagrams of each part in the normal phase rotation connection state and the negative phase rotation connection state of the embodiment shown in FIG. 4, respectively. be. 100...Inverter device, TH1, TH2,
TH3...Controllable electric valve, 1...Forward converter, S
1, S2, S3...Input terminals, V _R , V _S , V _T ...
Input power supply, 40... Phase rotation direction detection means, 30...
...Ignition means.

Claims (1)

[Claims] 1. In a power conversion device having a forward converter using a controllable electric valve, a synchronous power supply section that generates voltage pulses according to each phase of an input power source connected to an input terminal of the forward converter; input the voltage pulses of each phase output from the input power supply, and the switching point from positive to negative or from negative to positive of one phase or line voltage of the input power supply is in the positive half cycle of the other phase area or line voltage. ,
Depending on whether the input terminal is in a negative half cycle, it is detected whether the input power supply is connected to the input terminal in a positive phase rotation connection or in a negative phase rotation connection, and in response to the detection signal, the input terminal is connected in a negative phase rotation connection state. Phase rotation direction detection means that switches and outputs voltage pulses corresponding to each phase of the power supply so as to be connected in normal phase rotation; A power conversion device characterized by being provided with ignition means for igniting a converter.