JP2533848B2 - Ignition pulse generation method at power converter startup - Google Patents

Description

TECHNICAL FIELD The present invention relates to an ignition pulse generation method at the time of starting a forward conversion device or a cycloconverter.

[Conventional technology]

As for this kind of ignition pulse generation method, conventionally there is no particular distinction between starting and steady state, and an appropriate sawtooth signal (sawtooth signal) synchronized with the input power supply voltage is made for each arm and the signal is generated. It is generally well known to provide an ignition signal by comparing the output signal (control signal) with the current regulator output signal. For example, thyristors Thu to Thw, T as shown in FIG.
FIG. 8 shows the situation in the case where the 6-arm forward conversion device consisting of hx to Thz is operated at a controlled control angle. In FIG. 8, (a) shows the power supply phase voltage, (b) shows the relationship between the control signal S and the sawtooth signals (U-W, X-Z), and (c) shows the same. The relationships of the firing arms are shown respectively. When the non-circulating current type cycloconverter is operated by utilizing such a firing pulse generation method, the pulse generation circuit can be shared by the corresponding arms of the forward and reverse conversion devices. For example,
In the case of a non-circulating current type cycloconverter with three-phase input and one-phase output as shown in FIG. 9, the circuit as shown in FIG. The firing signal generating circuit has one circuit for each corresponding arm (for example, arms U _F and U _R ), that is, 6 circuits (11a to 11a).
f).

However, when such a conversion device is switched forward or backward,
Even if the output of the current regulator suddenly changes and the output current tries to rise sharply, the firing pulse is not output to the appropriate firing arm correspondingly, and thus the output current cannot rise sharply. For example, if the output of the current regulator changes as shown by S in FIG. 11 (b) during the forward / reverse switching of the cycloconverter as shown in FIG. 9, and if an ignition signal can be issued to the arms Y and U immediately after the change. , The current can be sharply raised. However, immediately after this switching, since there is no intersection between the current regulator output and the sawtooth signals of the arms Y and U, the firing signals are not output to the arms Y and U and the firing signals are output to the arms V and X. As a result, the output current cannot be rapidly raised. Therefore, when it is desired to quickly raise the output current, each arm of the forward and reverse converters is separately provided with a preparation circuit for generating an ignition signal for each arm, and an ignition signal generation circuit for a converter that is not in operation is provided. For the input of, instead of the output of the current regulator, put a signal that gives a control angle that causes the current to rise steeply, and give a firing pulse to the optimum arm during forward / reverse switching. Was there.

[Problems to be solved by the invention]

However, in such a method, since a firing signal generation circuit for each arm and a circuit for switching between the current regulator output and a signal for rapidly raising the current at the time of starting are required for each arm, the control is performed. There is a problem that the circuit becomes complicated and it takes time to adjust the circuit. Therefore, it is an object of the present invention to provide an ignition pulse generation method in which ignition control at the time of starting the power converter is simple and easy.

[Means and Actions for Solving Problems] 1. Prepare a counter whose count value also changes by one cycle while the input voltage is one cycle, and always use the counter at a specific phase of the input voltage of a specific phase. Set to start down or up count, 2. For each arm of all phases, create a correspondence table in advance between this counter value and the arm that should fire at a certain control angle, 3.At start-up, by shifting the counter value in the correspondence table by the value corresponding to the difference between the control angle used when creating the correspondence table and the control angle for actually starting the operation, which arm is pointed to By determining whether to ignite and applying a firing pulse to the arm, the firing pulse can be promptly applied to the optimum arm when the power converter is started.

Example of Invention

FIG. 1 is a block diagram showing an embodiment of the present invention when applied to a 6-arm forward conversion device. This is as follows: 1. While the input voltage makes one cycle, the count value also changes from D (constant; digital amount) to 1 as shown in Fig. 2, and 2. The current regulator output is digital. A / D converter 1 to be digitized and its A / D converter output down counter 2
A data converter 3 for converting a control angle equivalent value having the same weight as the output of 3., an initial control angle setting device 4 for giving a control angle at the time of starting, 4. a processing device 5 such as a microprocessor, 5. It is composed of an output port 6 required for transmitting a signal to the drive circuit 6 of each arm, and a memory 7 for storing the operation procedure and a correspondence table of counter values and arms to be fired. There is. Incidentally, a correspondence table of the counter value of the field with reference to a certain control angle, for example, 0 °, and the arm to be fired at that time is prepared in advance as shown in FIG. 3, for example. At the time of starting, the microprocessor 5 is operated according to the flow of FIGS. 4 and 5, the details of which will be described below.

1. Before inputting the "start" signal, the output port 6 is cleared (see Fig. 4), the down counter 2 is activated and waits for an interrupt (see Fig. 4).

2. When the "start" signal (interrupt signal) comes in, read the set values from the down counter 2 and the initial control angle setter 4 (see Fig. 5), then (counter value) ± (initial Control angle) (1) Is calculated (see FIG. 5).

3. When the calculation result based on the formula (1) deviates from the count values 1 to D in the correspondence table of the counter value and the arm to be fired, the value of the formula (1) is set so as to be the value in the table. Correct the results (see Figure 5). For example, in the case of the advance control angle, the result of Expression (1) may take a negative value,
In that case, a constant D is added to the result of the equation (1) for correction.

4. The arm to be fired is obtained by comparing the correction value of the equation (1) obtained in the above item 3 with the counter value stored in the memory 7 and the correspondence table with the firing arm ( (See Fig. 5),
A firing signal is output to the arm (see FIG. 5).

In the above example, the control angle at the time of creating the table is set to 0 °, but if it is not 0 °, the counter value may be shifted according to the order.

In this way, an ignition pulse can be quickly applied to the optimum arm at the time of starting. The steady-state ignition control is performed in the same manner as this, but it is omitted here because it has no particular relation to it. Further, although the counter is mainly described as a down counter in the above, in the case of an up counter, the correspondence of the positive and negative symbols of the above equation (1) with the delay and advance of the control angle is reversed to the extent that the down counter It can be applied as in the case.

Next, FIG. 6 shows another embodiment of the present invention which is applied to a non-circulating current type cycloconverter having three input phases and one output phase as shown in FIG. The difference between FIG. 6 and FIG. 1 is that the output from the output port 6 is divided into two for the forward conversion device (see thyristors Thuf to Thzf) and the inverse conversion device (see thyristors Thur to Thzr). AND circuit 9 (9a to 9l) is added to each output to make "forward" or "reverse"
The other points are the same as those in FIG. 1 except that the ignition signal is given only to the drive circuits 8a to 8f and 8g to 8l of either one of the forward and reverse conversion devices by the selection signal.

First, a case where the forward conversion device is operated in such a circuit configuration will be described.

1. Clear output port 6 as in the case of forward converter,
The down counter 2 is activated.

2. Input the "start" signal and "forward" signal at the same time. The ignition pulse generation method at the time of starting thereafter is the same as that of the case of the forward conversion device as described above.

3. During forward / reverse switching of the converter, (1) Input the pulse-off signal to return to the interrupt waiting state of the flow in Fig. 4 immediately. At this time, the "forward" signal is also reset.

(2) Input "start" signal and "reverse" signal at the same time to operate.

By repeating such a method, the ignition pulse can be given to the optimum arm of the cycloconverter as shown in FIG. In addition, in the case of this embodiment, the following advantages are obtained.

1. Each arm, that is, the firing signal generating circuit for each arm, which requires 12 circuits in total, can be replaced by one digital processing device as shown in FIG.

2. The correspondence table between the counter value and the firing arm shown in Fig. 3 can be shared by the forward and reverse converters, so only one correspondence table needs to be prepared.

3. Since the call pulse can be generated by the same procedure as the ignition pulse generation method of the forward converter, it can be applied to the cycloconverter without changing the program developed for the forward converter.

Although the single-phase cycloconverter has been described above, the present invention can also generate a starting pulse at the time of starting a multiphase cycloconverter in the same manner as above.

〔The invention's effect〕

According to the present invention, the ignition signal can be output to the optimum arm at the time of starting only by providing an initial control angle setter, a counter, and a correspondence table between the counter value at a specific control angle and the ignition arm. Only one digital processor can generate the starting arc pulses for all phases. In addition, in the case of a hybrid conversion device that has a delay control angle (separately excited) operation and a lead control angle (self-excited) operation that has the effect of reducing the input reactive power, refer to the correspondence table when the control angle is 0 °. By preparing only one, the ignition pulse for the starting point can be generated for both.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is a reference diagram for explaining a relationship between an input voltage and a counter value, and FIG. 3 is a correspondence relationship between the counter value and a firing arm. 4 is a flow chart for explaining the operation at power-on of the present invention, FIG. 5 is a flow chart for explaining the operation at the start of the present invention, and FIG. 6 is this flow chart. FIG. 7 is a block diagram showing another embodiment of the invention, FIG.
FIG. 8 is a circuit diagram showing a specific example of the arm forward conversion device, FIG.
FIG. 9 is a waveform diagram of each part for explaining the operation when the forward converter of the figure is operated at an advanced control angle, FIG. 9 is a circuit diagram showing a specific example of the non-circulating current type cycloconverter, and FIG. 10 is shown in FIG. Circuit diagram showing the corresponding firing pulse generation circuit.
FIG. 10 is a waveform chart of each part for explaining the operation of FIG. 10. Explanation of symbols 1 ... A / D converter, 2 ... counter, 3 ... data converter, 4 ... initial control angle setting device, 5 ... microprocessor (processor), 6 ... output port, 7 ... … Memory, 8 (8a to 8l) …… Drive circuit, 9 (9a to 9l), 12
(12a ~ 12l) ... AND gate, 11 (11a ~ 11f) ... Ignition signal generation circuit, Thu ~ Thz, Thuf ~ Thzf, Thur ~ Thzr ...
Thyristor.

Claims (1)

(57) [Claims] 1. A power converter connected to a power supply for supplying power to a load, a counter for repeatedly down- or up-counting one cycle of a predetermined input phase voltage with a predetermined control angle as a reference, and the counter value and its time point. A memory that tabulates and stores the correspondence relationship with the switching element of the power converter main circuit that should be ignited, and the switching element that should be ignited is determined by referring to the table based on the counter value. A digital processing unit for performing ignition control is provided, and the processing unit counts a value corresponding to a difference between a control angle used as a reference at the time of creating the table and a control angle for actually starting the operation when the power converter is started. At the time of starting the power conversion device, the switching element to be fired is determined by referring to the table after shifting the value. Firing pulse generation system.