JPS62285666A - Controller for power converter - Google Patents

Abstract

PURPOSE:To decrease the number of parts and the kinds of the parts by incorporating a program for a converter and a program for an inverter into one-chip microcomputer for control and selecting and starting one of these programs. CONSTITUTION:A three-phase AC power supply 1 is fed to an induction motor 7 as load through a converter section 3, a DC reactor 4 and an inverter section 5. The inverter section 5 is controlled by one-chip microcomputer 10. A program for controlling the converter section and a program for controlling the inverter section are each stored in program storage ROM areas 103A, 103B in one-chip microcomputer 10. A terminal 115 for selecting the programs of one-chip microcomputer 10 is controlled by an external signal, and the program for controlling the converter section or the program for controlling the inverter section is started.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a control device for a power conversion device, and is particularly suitable for a simple circuit configuration, reduction in converter cost, and improvement in reliability. The present invention relates to a control device for a power converter.

[Conventional technology]

Regarding using a one-chip microcomputer to control the inverter section of a power conversion device and also using a one-chip microcomputer to control the converter section to achieve a simple circuit configuration and at the same time improve performance and reliability, see the document title. "New Drive Electronics" (July 25, 1980, ■
It is described on page 217 of Denkishoinsha (Published by Denkishoinsha) and has been put into practical use. However, the control program for the inverter section and the control program for the converter section are significantly different in terms of their functions, and a microcomputer with a built-in dedicated program is custom-made and applied, or a ROM containing the program is used. The choice was made depending on the system, whether it was supported as an external device or not. Therefore, in the above case, for converters.

Two types of one-chip microcontrollers were required for the inverter, which increased manufacturing costs and made it difficult to manage each component. In the latter case, an external R
Since OM is required, there are problems such as an increase in the mounting space due to an increase in the number of parts, and a decrease in reliability.

[Problem that the invention seeks to solve]

The above conventional technology requires two types of one-chip microcomputers, one for the converter and one for the inverter, or requires an external ROM, which increases the number of parts and poses problems in terms of reliability.

The present invention improves the conventional drawbacks and uses simple hardware to reduce the number of parts in the control section of a power converter, reduce the number of parts, improve reliability, reduce costs, and reduce the number of parts management steps. The purpose is to

[Means for solving problems]

The above purpose focuses on the similarity of the pulse distribution functions of the converter section and the inverter section of a power conversion device.

In the program storage ROM area of the one-chip microcontroller,
This is achieved by storing a converter unit control program and an inverter unit control program, controlling a predetermined control bin of the one-chip microcomputer with an external signal, and activating the converter program or the inverter program. By doing so, it becomes possible to control pulse distribution of the power converter using one type of one-chip microcontroller without increasing the number of types of one-chip microcontrollers.

[Effect]

Generally, a ROM (read only memory) has a chip select terminal, which outputs an output signal when an active signal is input thereto, and is in a high impedance state when no active signal is input. Therefore, when the pulse distribution one-chip microcomputer is used for a converter, the output of the ROM for the inverter is set to high impedance, and when used for the inverter, the output of the ROM for the converter is controlled externally to set it to high impedance. By doing so, the purpose is achieved.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

1 is a three-phase AC power supply, 2 is an overvoltage suppression capacitor, 3 is a converter section, 31 to 36 are six transistors that constitute a current source converter, 4 is a DC reactor, 5 is an inverter section, and 51 to 56 are current source devices 6 Configuring the inverter
This transistor.

6 is a capacitor for overvoltage suppression, 7 is an induction motor as an example of a load, 8 is a DC current detector, 9 is a comparator for comparing the primary current command main 1- with the feedback value, 1
0.11 is a one-chip microcomputer that supplies pulse patterns to 12 transistors. Note that since 10 and 11 have the same configuration, the detailed internal explanation will be given using 10 as an example. 12 is a terminal for adding a primary current command main 1- given to the converter control system, and 13.14 is a terminal for adding a frequency command wi· and a phase command 0· to the inverter control system. A signal line 15 is an input line for a power synchronization signal to the converter control microcomputer. One-chip microcontroller 1
The inside of o is a command input port 1o1. Internal bus 1o2.
ROM 103A stores converter programs, pulse width data tables, etc.; ROM 103B stores inverter programs, pulse width data tables, etc.
, RAM10 used as temporary memory and registers
4. ALUI for performing calculations, etc. ○5. Output port 106
an event setting register 107 for setting an event to output a predetermined pulse pattern (event); and a time setting register 10 for setting a time for when to enable this event.
8. A holding register 109 that concatenates and holds the contents of both setting registers. An associative memory 110 in which several sets of setting data set in a holding register are stored, a comparator 112 that compares the timer 111 and the set time contents in the associative memory 110 and generates an output when they are equal to 1, and a comparator 112. Upon receiving the trigger, the execution controller 113 controls the output of the set event to the output port 106, and the program selection terminal 1
15, code conversion gate 114, etc.

Next, the operation in this configuration will be explained using a flowchart. However, here, the case of inverter control will be explained as an example. Since it is controlled by an inverter, a 5V signal is applied to the terminal 115 of the one-chip microcomputer from the outside.

Therefore, the chip select terminal CE of the ROM 103B becomes high (H), and this ROM is selected.

FIGS. 2 and 3 show flowcharts of two major processing systems.

FIG. 2 shows an event calculation processing program F100O for determining an event, that is, a pulse pattern, to be generated at the output port 106.
1 is a schematic flowchart. First, FIloo reads the frequency command ω1*1 phase command θ own from the input port 1o1. Of course, this ωl- and θ-fist are also one-chip microcontrollers 10
When calculating internally, port reading is not necessary. Next, this frequency command ω1 is integrated every fixed time Δt1, and is added to the phase command θ to obtain a total phase of 0. Processing F1
Find it in 2oo. Next, among the six modes in which the electrical angle of 36o° is divided into 60° increments, which mode should be used to output the pulse pattern for the total phase 0 that we have determined? Obtain by processing.

Note that the relationship between θT and the six modes will be explained in detail later. Finally, the pulse pattern is changed during the interrupt interval Δtz, and a process is performed in F1400 in which the time tEn until the change is determined is determined by referring to the data table with 0 units. Through this processing, the event details and event change times to be set in the two registers are determined.

Next, FIG. 3 shows a process F2000 in which the two previously determined items are set in the associative memory for output port control.

First, it is determined in F2100 whether the event setting and time setting necessary for the six transistors have been completed, and if NO, the corresponding event setting is performed in F2200, and the event change time setting is performed in F2300, and the process ends.

FIG. 4 shows how the two processes F1000 and F2000 are activated over time. The event setting process F2000 is activated in synchronization with a timer interrupt that occurs every Δtl. On the other hand, the event calculation process F100O is activated by a second timer interrupt that occurs prior to the timer interrupt, and is completed before F2000 is activated.

The reason I decided to complete the event calculation process F100O just before the event setting process F2000 was to update the latest data to F20.
This is because it can be used with 00. Of course, if it is acceptable to include a dead time element corresponding to the timer interrupt interval, use F200.
0 followed by FLOOO. In that case, the time required for interrupt determination becomes shorter, so the interrupt interval Δt
1 can be set short, making it possible to increase the frequency of the converter.

In the present invention, once the predetermined event and time settings are completed, the associative memory section within the microcomputer takes over control of the output port, thereby freeing the main processor section from output processing.

Next, the determination of the pulse pattern in process F1300 will be explained using FIG. Electrical angle 6 for inverter control
All you have to do is change the pulse pattern every 0° and repeat 6 sets of modes that go around 360°.Therefore, we selected 6 sets of modes M1 to M6 with an interval of 60° with a total phase of 0. . The flowchart is shown in FIG.

In addition.

360 if the 0th block appears in an area other than 0° to 36o°
A region check is performed at the beginning of Fl 300 to add and subtract degrees and bring θT back into the region.

Furthermore, in FIG. 6, in modes M1 to M6, a transistor is kept on for a period of Δ11, a transistor is on until an event occurs and then extinguished, a transistor is kept on until an event occurs, and a transistor is turned off until an event occurs. Each combination of transistors is then fired. Therefore, if the number 0 is known, the mode can be known and the transistor to be turned off and turned on can be specified. What is unknown at this point (when the process of F1300 is finished) is when to perform the vanishing point. Regarding ignition, for example, when setting an event, register II
The output is specified for each transistor by setting I and #OII for arc extinction.

In Figure 7, the process for determining the time to change the event (second
F1400) in the figure will be explained. In conclusion, it is sufficient to obtain a waveform close to a sine wave output, so the si
We used a method that distributes the interrupt interval Δt1 to the ratio of the peak value of nθ and 5 inches (60° - 0) with a 120" phase shift. In other words, the time tε until the event occurs (changing the pulse pattern) is Use the following formula to calculate the function for 0-cho, create a table, and search for 0-cho.

An example of a current source inverter is shown here, and since the inverter operates as a simple switch, it has the advantage of not requiring data table processing. When applied to a voltage source inverter, after searching the table, it is necessary to process the data in consideration of amplitude, etc.

FIG. 8 shows examples of operating modes and port output signals S51 to 55G given to transistors 51 to 56. The electrical angle variations in the modes are due to the asynchronous timer interrupt interval Δt1 with respect to the frequency command ω111. In order to eliminate this, it is possible to control Δt1 to be variable according to the ω1 fist.Let's take the first part of mode 1 in this figure as an example and explain the flowchart of the event setting process in detail. is shown in FIG. 9. In FIG. 3, a loop configuration is used for the sake of general explanation, but in reality, the processing is performed in series as shown in FIG.

This flowchart starts from time to in FIG. 8 to to+Δ1.
3 illustrates an event setting process for one timer interrupt period up to 1; First, when an interrupt occurs in to, an event set and a time are set so that an firing signal is immediately generated in the transistor (55) that always fires in this mode 1 in F2410 and the transistor (53) that fires until the event occurs. Do two sets for each transistor, i.e. 5
Set an event to generate "1" to ports 3 and 5 corresponding to ports 5 and 53, and then set the current time t as a time set.
A predetermined time td is added to o and set in a predetermined register.

Since ignition occurs immediately, td should be selected to have a sufficiently small value. As a result, the event and time are set in the associative memory, and 1'' signals are output to 55 and 53 after td has elapsed according to the schedule.

In the F2420, assuming that the operating mode has changed from the previous time due to a sudden change in the phase command θ, etc., in this mode, a process is performed to confirm the extinguishment of transistors that should be in the extinguished state.The process uses associative memory as in the F2410. However, since the event here is arc extinction, an event is set so that "0" is generated at ports 1, 2, and 4.6.

Next, at F2430, a schedule is processed in which the arc 53 is extinguished at time to+tf:n. The event is “
'O'' output and 1 time is set to+t!.

If td is a relatively large value, at this point, multiple events will have been scheduled at different times for one output port within the same timer interrupt.

Furthermore, in F2440, a schedule is set for ignition of 51 instead of extinguishing of 53. 6Here, the extinguishment of 53 and the ignition of 51 are set at the same time, but in order to prevent overvoltage, current source inverters use a "1" period. It is also possible to consider changing the period of tEn between F2430 and F2440 to create a non-lap period in the voltage type.

If the processes of F2410 to F2440 are completed in this manner, time comparison and output control are performed at predetermined time intervals in the associative memory section, and the ALU section is freed from output processing.

10 and 11, setting of multiple events for the same port within the same timer interrupt will be explained in detail. (a)
shows two sinusoidal curves and a pulse pattern S53 applied to the transistor 53 between to''to+Δt1, in this case, during the timer interrupt interval 611, port 3 is set to turn on and turned off at t6+t2n-t. The settings have been made twice.

On the other hand, in the example shown in FIG. 11, point arc extinction setting is performed four times during Δt1. This divides the timer interrupt interval Δtl into two sections, and in the first half, θ at time to
Δt ll 2 is distributed by the ratio of the sine wave peak value of T++-1, and in the latter half, the estimated value θT1 of 0 at time to+Δtz/2 is used. is obtained from θE1°on-Z, and based on this θTH, the residual Δt1/2 is distributed to the highest values of the sine wave. This produces the following effects. As shown in Figure 10 (c), which shows the operating state of the microcomputer, as the pulse generation interval is narrowed, the load factor (ratio of operating state to idle state) of the microcomputer increases, and the processing time essential for pulse width calculation etc. increases. Due to this relationship, a limit value naturally occurs in the timer interrupt interval Δt1.

This poses a major problem in increasing the frequency of power converters incorporating microcontrollers. On the other hand, the present invention has the feature that it is possible to set a plurality of events to the same port during the timer interrupt interval Δt1, making it possible to increase the frequency.

According to this embodiment, the following effects are achieved.

1) The I10 port built into one chip can be connected to a power converter directly or via a pulse amplifier, making the circuit configuration simple and highly reliable.

2) Since the configuration is such that a pulse pattern is completely created and output inside the one-chip microcontroller, an abnormality in the pattern is equivalent to an abnormality in the chip, and chip abnormalities can be countered by the microcontroller's self-diagnosis (for example, a watchdog timer, etc.) Therefore, the entire pulse pattern generator is monitored by the microcomputer, resulting in high reliability.

3) Changes in pulse patterns (events) are performed using an internal timer, but since event changes are always performed by the output control section including the associative memory, the ALU section does not output anything other than the process of setting the event and time in the register. This enables a division of labor system that is freed from processing and can run other user programs.

4) Events and times to be output from the same port can be set as many times as desired within the same timer interrupt interval as long as the number of storage registers allows, so the apparent chopping frequency of the inverter and converter can be increased. This makes it possible to increase the frequency of the power converter and realize a power converter with less ripple.

Next, a case where the present invention is applied to converter control will be explained.

In this case, in FIG. 1, the terminal 115 is grounded (GD) and the voltage is Ov. Then, the output of the code conversion gate 114 becomes high (H), and the ROM 10
3A is selected and the converter program is started. Concerning converter control, the processing becomes more complicated than the inverter control described above because the following two operations must also be performed in parallel. In other words, (1) in the case of an inverter, completely asynchronous would have been fine, but
In the case of a converter, it is necessary to synchronize with the power supply frequency.

(2) In the case of an inverter, a simple switch operation with a conduction rate of 1 is sufficient, but in the case of a converter, it is necessary to perform pulse width control that takes into account the value of the conduction rate of 0 to 1.

For synchronization (1), phase control used in conventional thyristor control is introduced, and in the case of inverter control, the event given to the associative memory is changed to pulse extinction command 1 (Q 11. "1").
'', this is a software timer interrupt event that interrupts the microcomputer itself, and the time is set to correspond to the phase data, and a series of schedules related to pulse switching starts from the moment this phase schedule operation is completed. I did it like that.

On the other hand, regarding (2), it is important to have separate time tables for various conduction rates as shown in Figure 7, and when the time until the occurrence of an event is long (there is ample time for various processes). We took into consideration the possibility of scheduling events and time settings for several subsequent events at a certain time.

Next, the main processing will be explained using a flowchart and a timing chart.

FIG. 12 shows the phase and pulse width command creation process F3000. F3200. In F3300, obtain the phase command ph and the conduction rate selection command γ. Of course ph.

It is also possible to create γ with an external analog circuit and input it by A/D conversion.

FIG. 14 shows power interrupt processing F4000.

For example, if the rising zero cross point of the U phase of a three-phase power supply is detected and an external interrupt is applied to the microcomputer, this interrupt will occur every 360 degrees of electrical angle.

When this interrupt is issued, an event is set in F4100 to issue a software timer interrupt to the microcomputer itself. Then, at F4200, F320 is set as the time of event occurrence.
Set the time corresponding to the phase command ph@ obtained at 0.

In inverter control, pulse switching processing is started by a timer interrupt that occurs at approximately regular intervals, whereas in converter control, this power supply interrupt processing F4000 starts a series of pulse switching processing after the power supply interrupt and the following phase time. will be done.

FIG. 15 shows phase completion interrupt processing F5000. This process is activated when the phase time set in power interrupt process F4000 is reached. First, F5100 writes "1" as an event to the port for transistors 33 and 35 that should be fired immediately, adds a small dummy time td to the current time to, and registers the operation in associative memory.6 Next, F5200 writes the following Event setting and time setting of 11 Q II and it l 11 are performed for the transistors 33 and 32, respectively, which are to be turned on and off.

The time Tw is determined by referring to a table from the conduction rate command γ- and the pulse width data. In addition, the F5300 sets a self-interrupt event at the above time Tw in preparation for the next pulse switching by issuing a self-interrupt at the time of the pulse switching set above.The F5400 sets the jump destination in the program for the next pulse switching process in advance. Perform the required processing.

FIG. 16 shows the beginning of the pulse switching process F6000. This part is executed following the phase completion interrupt process F5000. First, in F6010, setting of events "0" and "1" and time setting are scheduled for the next extinction-ignition transistors 31 and 32. Next, the event and time of the variable software timer interrupt that is applied to itself at the time scheduled in F6010 is F6020.
is set. Next, in F6030, pulse switching processing F
Find the destination when 6000 is activated. Here, the reason why Fe2O2 was used as sequence processing was because it was desired to set the minimum pulse width narrower by shortening the time required for jump destination determination. Next, pulse switching processing F6
The jump destination is set in F6030 so that when 000 is activated, the program jumps to the next line after F6030.

Next, FIG. 17 shows how the above-described process is activated over time. A power supply interrupt process F4000 is started by a power supply interrupt signal generated every 360'' electrical angle, and a phase completion interrupt process F5000 scheduled in F4000 is started after a time corresponding to the phase data Ph, and further scheduled in F5000. The pulse switching process F6000 is started at the time of extinction.

A specific example of the occurrence of the pulse switching process F6000 shown in FIG. 16 is shown in FIG. 18. Here, the electrical angle 60' section is shown, and the other sections differ only in the pulse distribution destination as in the case of inverter control. Therefore, it will be omitted. The conductivity command γ- ranges from 0 to 1, but here, γ-=0.75 is taken as an example. Roughly speaking, the γ pair pulse width data table is turned around at an electrical angle of 30" with four lines shown as solid lines, broken lines, and dotted lines. First, the phase completion interrupt process is activated. F5100゜F
5200. F5300, which corresponds to mode 1-1 in FIG. Transistors 33 and 35 are scheduled to fire immediately, 33 is extinguished after 1st Tl, and 32 is scheduled to be turned on, and mode 1-2 is set to 1st Tl.
Schedule it to start later. This mode 1-
In Mode 1, the vanishing point T1 for the value of γ- is determined by simply referring to Table 1, but in the next mode 1-2, the vanishing point Tz is determined by referring to Tables 1 and 2. You need to decide. Furthermore, as discussed here, γ
For example, if the fist value is large, mode l-3, 1-1
If it is 0, etc., inconvenience will occur. That is, mode 1-3.1
-10 is the pulse switching point (that is, the next mode 1-4.
1-11) is short, and the associative memory may not have enough time to schedule a vanishing arc, set an interrupt event for itself, etc. This phenomenon is γe
If the value of is small, mode 1-1.1-3°1-4.
1-6. Occurs at l-7, 1, -9, 1-10, 1-12, etc. In consideration of such a phenomenon, the pulse switching process F60 sets a plurality of extinguishing schedules in the associative memory between the same timer interrupts with reference to the value of γ umbrella.
It is set in 00. An example of this is shown in Figure 19.Here, we will explain the flow from mode 1-2 to mode 1-3.1-4 as an example, but the same idea can be applied before and after the other narrow modes mentioned above. Applicable. This sets the value of γ fist to F
6050, and if the value is small, it is determined that the time of the next mode, Mode 1-3, is short, and the mode 1-2 is
Vanishing arc processing F6080 that should be performed in the next 1-3 during the processing of
They end up doing the following. Therefore, the mode to be executed next after mode 1-2 is 1-4, so the jump destination is mode 1-4 in F6090, and the interrupt set to be applied to itself in F6100 is not after Tz, but ('rz+
T3) Wait for the next interrupt later.

Of course, if γ- is sufficiently large and modes 1-3 can be executed, F6060. By using multiple schedule processing within the same timer interrupt, such as F6070(7)/L/-, which does not skip modes, it is possible to generate narrow pulses that would be impossible with normal interrupt processing. Therefore, it has the effect of opening up possibilities for harmonic reduction control.

In the above explanation, we have explained the method of setting events one port at a time due to the relationship between the execution controllers, but in a one-chip microcontroller of the type that can set all six ports at the same time, for example, the processing shown in Figure 9 can be changed as shown in Figure 20. This simplifies the process and reduces the number of microcomputer instruction lines from, for example, 16 lines to 4 lines.

゛・, [Effects of the Invention] As described above, according to the present invention, a one-chip microcomputer with a built-in converter control program and an inverter control program can be used for the converter by externally connecting it with terminals,
Alternatively, since it can be selectively used for an inverter, it is sufficient to develop one one-chip microcomputer for use in a power conversion device, and it is possible to reduce development costs and the unit price of a one-chip microcomputer.

Additionally, since there is only one type of one-chip microcontroller, there is no confusion between converter and inverter applications when mounting printed circuit boards.

In addition, in the above example, a dedicated terminal was provided for program selection, and the application was selected by controlling this. However, the interrupt terminal of the one-chip microcontroller is used, and when there is an interrupt, the inverter program is selected. , it is also possible to select a converter program when there is no interrupt, but the same effect can be obtained.

[Brief explanation of drawings]

FIG. 1 is an overall configuration of the present invention, FIGS. 2 to 11 are diagrams for explaining the present invention in detail, and FIGS. 12 to 20 are diagrams for explaining other embodiments of the present invention. It is. 3...Converter section, 5...Inverter section 1.10
゜11...One-chip microcomputer, 31~36.51~
56...Transistor, 103A...ROM for converter, 103B...ROM for inverter, 106.
...Output port, 107...Event setting register, 10
8... Time setting register, 109... Holding register, 110... Associative memory, 111... Timer, 11
2... Comparison unit, 113... Execution controller. 114... Code conversion gate, 115... Terminal, F
1000...Event calculation processing, F2000...Event setting processing, F3000...Phase conduction rate command creation processing,
F4000...Power supply interrupt processing, F5000...Phase completion interrupt processing, F6000...Pulse switching processing, ω1 fist...Inverter frequency command, θ Season...Inverter phase command, 0th... Total phase of inverter, tE... Time until event occurrence, Δt1... Fixed timer interrupt interval, Δi1... Current deviation, ph...
Converter phase command, r-... converter conduction rate command, M1 to M6... mode.

Claims (1)

[Claims] 1. A power converter comprising a power converter having a converter section and an inverter section, and a control one-chip microcomputer having a plurality of output ports connected to each control element of the power converter directly or via a pulse amplifier. The control device is characterized in that a converter program and an inverter program are built into the one-chip control microcomputer, and one of the two programs is selectively activated depending on external signal conditions. Power converter control device.