JPH0251359A - Digital phase shifter - Google Patents

Abstract

PURPOSE:To improve responding properties of control by comparing a value corresponding to the elementrical angle of AC voltage with a value corresponding to an angle of delay command through a comparator and by selecting the output of said comparator as the ignition command of a specified rectifier bridge. CONSTITUTION:A power converter is composed of a gate-pulse generator 9, a rectifier 11 and a transformer 10, and the main circuit of said converter receiver an AC power from a stringing 14 obtained via a pantograph 9 by a transformer 10 to drive a load 12 such as motor via said rectifier 11. Also, a digital phase shifter is composed of a counter 1 counting a clock signal 27 and being reset by the zero-cross signal of AC voltage to output data, flip flops 2, 5, 7 latching an angle of delay command 28, etc., a comparator 3, a demultiplexor 4, and a logical circuit 6. Thus, a value corresponding to the electrical angle of AC voltage and said angle of delay command are compared by a comparator 3 and the result of said comparison is outputted as an ignition command.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a control device for a 111 force converter, and in particular to a digital transfer device suitable for use in phase control of a power converter such as an AC electric vehicle. Regarding phase equipment.

[Prior Art] As a conventional technique related to a phase shifter used for performing phase control of a power converter, a technique is known that generates a phase shift pulse in accordance with a control delay angle command from a microcomputer or the like. Hereinafter, an example of this kind of conventional technology will be explained with reference to the drawings.

FIG. 5 is a block diagram showing the configuration of an example of a phase shifter according to the prior art, and FIG. 6 is a waveform diagram illustrating its operation. In FIG. 5, 41 to 44 are timers.

The prior art shown in FIG. 5 uses timers 41 to 44 as phase shifters. These timers 41 to 44 are the sixth
Zero cross signal 15 of AC voltage 14 which is the power supply shown in the figure
act as timing signals, and their outputs are used to control one stage of the corresponding rectifier bridge, respectively.

The waveform diagram shown in FIG. 6 explains the operation of one timer, for example, timer 41. In FIGS. 5 and 6, the control delay angle command 45 is controlled by the timer 41.
commanded as a preset value. This control delay angle command 45 is taken into the timer 41 in synchronization with the zero cross signal 15 of the AC voltage 14, and the timer 41 immediately starts subtracting the given command 45. Then, the timer 41 outputs a rectifier bridge eight-ignition signal 46 when the count value reaches 0''.This firing signal 46 receives the command 45 into the timer 41 by the primary zero-cross signal 15. Therefore, in the prior art shown in FIG. 5, by changing the magnitude of the control delay angle command 45 given to the timer 41, The width can be adjusted. The other timers 42 to 44 similarly output firing signals 46 that control the corresponding rectifier bridges in response to control delay angle commands applied to them.

In addition, as prior art related to the above-mentioned phase shifter, for example, Japanese Patent Application Laid-Open No. 57-168315 and Japanese Patent Application Laid-open No. 60-
A technique described in Japanese Patent No. 96194 and the like is known.

[Problems to be Solved by the Invention] In the prior art, since the count value of the timer changes every moment, it is difficult to change the control delay angle command 45 at an arbitrary timing.

It is almost impossible to change the control delay angle command 45 multiple times within a half period of the power supply voltage. For this reason, in the conventional technology, it is difficult to make the control respond quickly, and for example, when there is a disturbance such as a fluctuation in the power supply voltage, the control delay angle command is immediately changed and the The problem was that it was difficult to reduce the

Further, the conventional technology has a problem in that when controlling a power converter equipped with a plurality of rectifying bridges, the same number of phase shifters as the number of rectifying bridges are required.

An object of the present invention is to solve the problems of the prior art described above, to improve the responsiveness of control by making it possible to change the control delay angle command at any timing, and to improve control responsiveness even when there are a plurality of rectifying bridges. It is an object of the present invention to provide a digital phase shifter that allows these to be controlled with one phase shifter.

[Means for Solving the Problems] According to the present invention, the object is to compare a value corresponding to the electrical angle of the AC voltage and a value corresponding to the control delay angle command by a comparator, and to calculate the output of the comparator. This is achieved by selecting the specified rectifier bridge and using it as the firing command.

[Operation] One input of the comparator is given a value corresponding to the electrical angle of the AC voltage, and the other input is given a control delay angle command. These magnitude relationships are then compared by a comparator, and the comparison result is output as an ignition command. According to such a configuration, there is no need to change the control delay angle command depending on the electrical angle of the alternating current (in the prior art, when it is desired to change the control command at a point other than the zero-crossing point of the alternating current voltage, (It is necessary to change the command value according to the electrical angle.), it becomes possible to change the control delay angle command at any timing.

Also, if the output of the comparator, that is, the firing command, is given as a firing command to a certain rectifier bridge by a selection circuit such as a demultiplexer, and an on or off command is given to other rectifier bridges. ,1
It becomes possible to control multiple rectifier bridges with a single phase shifter.

[Embodiment] Hereinafter, an embodiment of the digital phase shifter according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, and FIG. 2 is a waveform diagram explaining its operation.

In FIG. 1, 1 is a counter, 2, 5, and 7 are flip-flops, 3 is a comparator, 4 is a demultiplexer,
6 is a logic circuit, 8 is a gate pulse generator, 9 is a pantograph, 10 is a transformer, 11 is a rectifier, 12 is a load, 14
is an overhead wire.

One embodiment of the digital phase shifter according to the invention, shown in FIG. Counter 1 that outputs corresponding data. Flip-flop 2 for latching the control delay angle command 28. A comparator 3 that compares the output of the counter 1 and the output of the flip-flop 2, a demultiplexer 4 that switches the output light of the comparator 3, a flip-flop 5 that latches the firing command 29, and a logical operation of the outputs of the demultiplexer 4 and the flip-flop 5. The logic circuit 6 includes a logic circuit 6 that performs the following, and a flip-flop 7 that holds the output of the logic circuit 6 until a zero-cross signal 15 is applied.

The power converter to be controlled by the digital phase shifter according to the embodiment of the present invention configured as described above is, for example,
This is the main circuit in an AC electric vehicle, and is composed of a gate pulse generator 8, a rectifier 11, and a transformer 10.

In this main circuit, a transformer 10 receives AC power from an overhead wire 14 obtained via a pantograph 9, and a rectifier 11
A load 12 such as a vehicle drive motor is driven through the motor. The rectifier 11 is composed of a plurality of rectifier bridges connected in series, and one rectifier bridge is controlled by a gate control signal given from the gate pulse generator 8, and the other rectifier bridges are turned on or off. and its output voltage is controlled.

In the waveform diagram shown in FIG. 2, the triangular wave 16 is an analog signal representing the output of the counter 1 that counts the clock 27, and corresponds to the electrical angle of the AC voltage 14. Moreover, the step-like waveform 17 is the control delay angle command 28
This is a control delay angle command that is output after being once latched by the flip-flop 2 that receives the control delay angle. The comparator 3 compares the output of the counter 1 and the output of the flip-flop 2, and generates an output when the output of the flip-flop 2, that is, the control delay angle command 17 becomes large. This output is a phase-shifted signal whose pulse width increases as the control delay angle command 17 increases, and serves as a firing signal for the rectifier bridge, as shown in a waveform 18. This signal is input to the demultiplexer 4.

Now, let us focus on the two outputs 20°21 of the demultiplexer 4. When the control signal 19 is '0'', the demultiplexer 4 sends the input signal 18 to the output 20,
Furthermore, when the control signal 19 is tlIll, the phase shift signal 1
It is assumed that the control signal 19 is "0" and the outputs 22 and 23 of the flip-flop 5 are "0" before time t1. The flip-flop 5 receives the ignition command 29 and latches information indicating which rectifying bridge in the rectifier 11 is to be turned on.

In the state before the aforementioned time t1, the control signal 19 is HOIT.
Therefore, the phase shift signal 18 is transmitted to the output 20 of the demultiplexer 4 and applied to the logic circuit 6. The output 22 of the flip-flop 6 applied to the logic circuit 6 is “O”
Therefore, the phase-shifted signal 1゛8 from the output 20 is
In this state, until the next zero-crossing signal, this phase shift signal 18 is applied to the gate pulse generator 8 as an ignition command signal 24 via a flip-flop that latches it.

The gate pulse generating circuit 8 thereby applies a gate control signal based on the phase shift signal 18 to the first rectifying bridge at the lowest stage of the rectifier 11 to control the rectifying bridge. At this time, in the other rectifier bridge, at time t1, the control signal 19 of the demultiplexer 4 becomes ``1'', and the output 22 of the flip-flop 5 becomes ``1''. As a result,
The phase shift signal 18 is passed through the output 21 of the demultiplexer and the logic circuit 6° flip-flop 7 to the firing command signal 25.
The signal is applied to the gate pulse generator 8 as a signal. In addition, since the output 22 of the flip-flop 5, that is, the firing command for the first rectifying bridge becomes ``1'',
The firing command signal 24, which is the output of the flip-flop 7, is
This becomes the signal of the control delay angle II Olj. The gate pulse generator 8 thereby controls the first rectifying bridge at the lowest stage to be in the on state, and applies a gate control signal based on the phase shift signal 18 to the second rectifying bridge at the next stage. and control the rectifier bridge. At this time, the other rectifier bridges located further above are in the off state, so the output voltage of the rectifier 11 is changed to the output voltage that is not controlled by the first rectifier bridge, and the output voltage of the rectifier 11 is changed to the output voltage that is not controlled by the first rectifier bridge. The output voltages are added to form a waveform 26 after time t1. By continuing such control, the output voltage of the rectifier 11 is controlled to gradually increase. Do the same.

It is also possible to perform control to lower the output voltage of the rectifier 11.

The embodiment of the present invention described above performs gate control on one of the rectifying bridges in the rectifier 11 in the manner described above using the control delay angle command 28 and the ignition command 29, and turns on or off the other rectifying bridge. Since it can be turned off, it is possible to control a rectifier made up of multiple rectifier bridges connected in series with a single phase shifter, and changes in control delay commands can be performed using AC voltage electricity. It can be performed at any time without being restricted by corners, making it possible to perform highly responsive control.

FIG. 3 is a block diagram showing the configuration of another embodiment of the present invention;
FIG. 4 is a waveform diagram explaining the operation.

In FIG. 3, 13 is a ROM, and other symbols are the first
This is the same as the case shown in the figure.

Another embodiment of the present invention shown in FIG. 3 uses the output of the counter 1 as the address signal of the ROM 13, and
This embodiment differs from the embodiment shown in FIG. 1 in that the signal 7 is applied to the comparator 3 as a signal corresponding to the electrical angle of the alternating current voltage 14, but otherwise the structure is the same.

Generally, in phase control of AC voltage, the ratio of the DC output voltage of the rectifier to the AC voltage is expressed as follows, if the control delay angle is α:
(1+cosα)/2. Therefore, in the embodiment of the present invention shown in FIG. 3, the data in the ROM 13 is set to output a waveform of (1+cosα)/2, as shown in waveform 27 in FIG. The embodiment shown in the figure is
Thereby, the control delay angle command 28 and the output voltage of the rectifier 11 can be made to have a proportional relationship, and nonlinearity can be canceled, so that control performance can be improved.

Although the embodiments of the present invention described above have been described as being used to control a rectifier in the main circuit of an electric vehicle, the present invention can also be used in other technical fields such as changing the DC voltage applied to a load. .

[Effects of the Invention] As explained above, according to the present invention, since the control delay angle command can be changed at any timing, the control can be performed in response to disturbances such as fluctuations in the power supply voltage at high speed. It is possible to adjust the delay angle command, improve control performance such as reducing the influence of disturbances, and even when multiple rectifying bridges are provided, the present invention Since this can be handled by a phase shifter according to the present invention, it is possible to downsize a control device particularly for controlling a rectifier having a multi-stage configuration.

Further, according to the present invention, by using the ROM, it is possible to generate a signal in which the control delay angle command and the rectifier output voltage are in a proportional relationship, so that nonlinearity between the command and the output voltage can be canceled out. This makes it possible to further improve control performance.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of one embodiment of the present invention, FIG. 2 is a waveform diagram explaining its operation, FIG. 3 is a block diagram showing the configuration of another embodiment of the present invention, and FIG. 4 5 is a block diagram showing the configuration of an example of the prior art, and FIG. 6 is a waveform diagram explaining the operation. 1...Counter, 2,5.7...Flip-flop, 3...Comparator, 4...
...Demultiplexer, 6...Logic circuit, 8
......Gate pulse generator, 9...Pantograph, 10...Transformer, 11...
Rectifier, 12...Load, 13...RO
M, 14... Catenary. Figure 4

Claims (1)

[Claims] 1. In a phase shifter that generates a firing command for a rectifying bridge, means for outputting a signal corresponding to the electrical angle of the power supply voltage, means for holding a control delay angle command, and these means and means for holding the output of the comparing means until the next zero-crossing position of the AC voltage,
A digital phase shifter characterized in that the output of the means for holding the output of the comparison means is outputted as an ignition command. 2. The digital phase shifter according to claim 1, further comprising distribution means for distributing the output of the comparison means to one of the plurality of rectifying bridges. 3. The method according to claim 2, further comprising means for performing a logical operation on the output of the distribution means and a firing command for another rectifier bridge that is not controlled by the output of the distribution means. Digital phase shifter. 4. The digital phase shifter according to claim 1, 2 or 3, wherein the means for outputting a signal corresponding to the electrical angle of the power supply voltage is constituted by a counter. 5. The digital phase shifter according to claim 1, 2 or 3, wherein the means for outputting a signal corresponding to the electrical angle of the power supply voltage is constituted by a ROM.