JP2533849B2 - Ignition pulse generation method in power converter - Google Patents

Description

The present invention relates to a firing pulse generation system for a forward conversion device or a cycloconverter.

[Conventional technology]

As this type of firing pulse generation method, conventionally, an appropriate sawtooth signal (sawtooth signal) synchronized with the input power supply voltage is made for each arm, and the signal and the current regulator output signal (control signal) It is generally well known to provide an ignition signal by comparison. For example, FIG. 12 shows the situation in the case of operating the separately excited conversion device including the thyristors Thu to Thw and Tkx to Tkz as shown in FIG. 11. In addition,
In FIG. 12, (a) shows the power supply phase voltage, (b) shows the relationship between the control signal S and the sawtooth signals (U to W, X to Z), and (c) shows the firing arm. The relationship of each is shown.

[Problems to be solved by the invention]

However, in such a firing pulse generation method,
Each arm requires one sawtooth signal generation circuit and one comparison circuit, which complicates the firing pulse generation circuit and also requires a lot of time to adjust the circuit.

Therefore, an object of the present invention is to provide an ignition pulse generation system capable of easily and easily generating an ignition pulse.

[Means and Actions for Solving Problems]

In a power converter that can sequentially determine the firing order of arms, the arm to be fired next to the newest firing signal is determined, and when to fire the arm to be fired next. This was done by paying attention to the fact that it is possible to give a firing pulse to the arm appropriately if only how it is known. Prepare a counter that also changes the value by one cycle, and set the counter so that the down or up count is always started at the specific phase of the input voltage of a certain specific phase. 2. For each arm of all phases in advance, In the case of a specific control angle, the counters calculate the values corresponding to the times to be fired, and the values are tabulated in correspondence with each arm. 3. During operation, (1) Immediately after outputting the ignition signal to a certain arm, the next ignition arm and the ignition time equivalent value corresponding to that arm are immediately obtained from the above correspondence table (table), and (2) the control used when creating the correspondence table. The ignition time equivalent value obtained in (1) is shifted by a value corresponding to the difference between the angle and the actual control angle, and whether the ignition signal is output by comparing the value with the counter value. By making a judgment, the ignition pulse of the power converter is sequentially given.

Example of Invention

Fig. 1 shows an embodiment of the present invention when applied to a 6-arm forward conversion device. 1. The count value is D (constant; Down counter 2 that changes from digital value) to 1. 2. A / D converter 1 that digitalizes the current regulator output, and its A / D converter output is equivalent to a control angle with the same weight as the output of the down counter Data converter 3 for converting into a value to be controlled, 3. initial control angle setting device 4 for giving a control angle at the time of starting, 4. processing device 5 such as a microprocessor, 5. drive circuit 8 (8a) of each arm ~ 8f) output port 6 required to transmit a signal, and 6. the operating procedure, the correspondence table between the counter value used at the time of starting and the arm to be fired, and each arm at a specific control angle used in the steady state. The counter value to fire And a memory 7 for storing the correspondence table of.

First, at the time of starting, the digital processing apparatus 5 is operated according to the flow charts of FIGS. 3 and 4, the details of which will be described below. Here, it is assumed that the correspondence between the counter value and the arm that should be firing at that time when the control angle is 0 ° is stored in advance in the memory 7 as shown in FIG.

1. Clear the output port 6 (see Fig. 3) before the "start" signal (interrupt signal) is input, and down counter 2
Is activated to wait for an interrupt (see Fig. 3).

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. 4), then (counter value) ± (initial control Corner) …… (1) (See FIG. 4).

3. When the calculation result based on formula (1) deviates from the count values 1 to D in the correspondence table between the counter value and the arm to be fired, the result of formula (1) is set to the value in the table. Is corrected (see FIG. 4). 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 section 3 with the counter value stored in the memory 7 and the correspondence table of the firing arm (fourth step). (See FIG. 4), and issues a firing signal to the arm (see FIG. 4).

In this way, it is possible to quickly give a firing pulse to the optimum arm at the time of starting.
This will be described with reference to FIGS. Also in this case, a table (correspondence table) showing the relationship between the counter value corresponding to the ignition timing of each arm and the ignition arm when the control angle is 0 ° is stored in advance in the memory 7 as shown in FIG. It is stored.

1. Referring to FIG. 7, from the previously issued ignition signal, the arm to be fired next and the counter value for firing that arm at a control angle of 0 ° (hereinafter, this value is the reference for the next firing). (Referred to as a value) (see FIG. 6). For example, if a firing pulse was given to the V arm last time, the next firing arm is X
It is an arm, and it can be seen that the next firing reference value is D / 2.

2. The control angle is read every moment from the data converter 3 (see FIG. 6), and it corresponds to the difference between the control angle and the control angle (control angle 0 ° in this embodiment) used as a reference when creating the table. The next ignition reference value is shifted according to the following formula (see FIG. 6) according to the value to be set (the next ignition timing correction value).

(Next ignition timing) = (Next ignition reference value) (Next ignition timing correction value) (2) However, the symbols are (−) for the delay control angle and (+) for the advance control angle. .

3. When the result of the equation (2) is out of the output range (D to 1) of the counter, that is, when it is less than 0 or exceeds D,
D is added to or subtracted from the result of equation (2) to correct the result so that it falls within the output range of the counter (see FIG. 6).

For example, in the case of the delay control angle, the result of the equation (2) becomes negative and sometimes deviates from the output range of the counter. However, at this time, by adding D to the result of the equation (2), the result falls within the output range of the counter. Can fit.

4. The next ignition reference value shifted in 2 (or 3) above is compared with the counter value of the counter to output the next ignition signal. Has a point (update point) at which its value changes discontinuously from 1 to D. When the update point is exceeded, the criterion for determining whether to issue the roll call signal changes, so it is determined by the following equation whether the counter value and the next ignition timing correction value have exceeded the update point (see FIG. 6).

(Next ignition timing correction value) ≧ (counter value) (3) An ignition signal is output to the arm to be fired only when the above expression (3) is satisfied (see FIG. 6), and the expression (3 ) Is not established, the process returns to the step “reading control angle”.

Here, if either the counter value or the next ignition timing correction value exceeds the update point, an erroneous ignition signal will be output only by the determination of the above equation (3).
Further, the following operation is performed.

(1) When only the counter value exceeds the update point (when the step proceeds from →→→), a firing signal is sent to the arm to be fired. (In this method, since the counter value is not continuously read, if the next ignition correction value is very small, the counter value may exceed the update point without reading the counter value below that value depending on the timing. (This is a countermeasure in that case.) (2) When only the next ignition correction value exceeds the update point (when the step proceeds from →→→), the control angle is read.

6. After sending the firing signal to the arm to be fired in this way, the process returns to the step to read the next firing arm and the next firing reference value.

By repeating such a procedure, it is possible to output appropriate ignition signals one after another. In the above example, the control angle at the time of creating the table is 0 °, but if not, the ignition timing reference value is shifted according to the value.

Next, another example of the present invention applied to a non-circulating current type cycloconverter of three-phase input and one-phase output as shown in FIG. 8 is shown in FIG. The difference between FIG. 9 and FIG. 1 is that the output from the output port 6 is used for the forward conversion device (see thyristors Thuf to Thzf) and the inverse conversion device (thyristor Th).
ur ~ Thzr) and AND for each output
Circuit 9 (9a-9f, 9g-9l) is added, and only the drive circuit 8a-8f, 8g-8l of either the forward or the reverse converter is selected by the "forward" or "reverse" selection signal. The other points are the same as in FIG. 1 except that an arc signal is input.

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

1 As in the case of the forward converter, the output port 6 is cleared and the down counter 2 is activated.

2. Input “Start” and “Forward” signals at the same time. The method of generating the ignition pulse at the time of starting and after that is the same as the method of the forward converter 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. 3 immediately. At this time, the "forward" signal is also reset.

(2) Simultaneously input the "start" signal and the "reverse" signal 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. Since the correspondence table between the firing arm and the firing timing reference value shown in Fig. 7 can be shared by the forward and reverse converters, it is only necessary to prepare one correspondence table.

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

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

〔The invention's effect〕

According to the present invention, a firing pulse can be sequentially generated using a table in which each arm at a specific control angle and counter values to be fired are arranged in firing order, an actual counter value, and a control angle command. Therefore, even if the power converters are multiplexed, by subdividing the correspondence table between each arm and the counter value to be fired, it is possible to give firing pulses to all arms by one digital processing device. For example, in the case of a 12-pulse converter, the correspondence table between each arm and the counter value to be fired may be subdivided as shown in FIG. 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 can be sequentially given to 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 diagram for explaining an operation at power-on of the present invention. FIG. 4 is a flow chart for explaining the operation at the time of starting of the present invention, and FIG. 5 is a reference diagram for explaining the relationship between the counter value and the ignition arm at the time of starting, and FIG. Is a flow chart for explaining the operation in the steady state in the present invention, FIG. 7 is a reference diagram for explaining the correspondence relationship between the ignition arm and the next ignition reference value in the steady state, and FIG. 8 is the non-circulation. FIG. 9 is a circuit diagram showing a specific example of a current source cycloconverter, FIG. 9 is a configuration diagram showing another embodiment of the present invention applied to the cycloconverter of FIG. 8, and FIG. 10 is a firing arm in a 12-pulse converter. And the next ignition reference value will be explained. FIG. 11 is a circuit diagram showing a specific example of the 6-arm forward conversion device, and FIG. 12 is a waveform diagram of each part for explaining the operation of the forward conversion device shown in FIG. 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-8l) …… Drive circuit, 9 (9a-9l) ……
Andgate, Thu ~ Thz, Thuf ~ Thzf, Thur ~ Thzr ... Thyristor.

Claims (2)

(57) [Claims] 1. A power converter connected to a power supply for supplying power to a load, comprising: a counter that repeatedly down-counts or up-counts one cycle of a predetermined input phase voltage based on a predetermined control angle; and the power converter. A memory for tabulating and storing the correspondence between the firing timing reference value and the firing arm, which serves as a reference when each switching element (arm) is sequentially fired at a predetermined control angle, and the contents of the table and the counter. A digital processing device that performs the roll control by determining the arm to be fired next from the value and its timing is provided, and during steady operation of the power converter, the processing device is based on the latest firing pulse. Next, the arm to be fired and the firing timing reference value when firing the arm at a predetermined control angle are obtained, and the control used as the reference when the table is created. And,
The ignition timing reference value is shifted by a value corresponding to the difference between the actual control timing and the ignition timing reference value, and an ignition signal is output based on the result of comparison between the shifted ignition timing reference value and the counter value. A method for generating an ignition pulse in a power conversion device, which is characterized by sequentially performing the following operations. 2. The ignition pulse generating method in the power converter according to claim 1, wherein when the ignition timing reference value is shifted, whether the control angle is a delay control angle or a lead control angle. Discriminating the ignition timing and shifting the ignition timing reference value according to the polarity of the ignition pulse generation method in the power conversion device.