JPH0667207B2 - Power converter controller - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a power converter control device, and particularly to a power converter suitable for improving reliability of a power converter that switches a self-extinguishing element at a high frequency. Control device.

[Prior Art] Conventionally, in a power converter that switches a self-extinguishing element, as a method for suppressing a temperature rise of the self-extinguishing element and preventing a decrease in reliability of the power converter, a practically developed method is disclosed.
There is one disclosed in Japanese Patent Publication No. 96. This conventional technology detects the temperature of the self-extinguishing element with a temperature sensor, and sets the maximum allowable switching frequency of the self-extinguishing element according to the detected temperature of the self-extinguishing element. The above switching loss is suppressed.

However, this prior art is to increase or decrease the carrier frequency equivalent to the switching frequency, to increase or decrease the switching frequency in an indirect manner, and to directly control the switching frequency itself of the self-extinguishing element. However, various additional circuits are required to stably switch the self-extinguishing element. That is,
Self-extinguishing element Maximum allowable frequency setting circuit that sets the maximum carrier frequency according to the temperature of the element, Frequency comparison circuit that compares the currently operating carrier frequency with the maximum allowable carrier frequency, Self-extinguishing when the switching frequency changes Minimum on-pulse securing circuit to secure the minimum on-time of the element, failure detection circuit added to the switching frequency variable part to prevent the permanent destruction of the system by operating the self-extinguishing element at an abnormal switching frequency Etc.

[Problems to be solved by the invention]

As described above, the control device for the power converter according to the related art requires various additional circuits in order to suppress the temperature rise of the self-extinguishing element to be switched, and the control circuit becomes complicated. There are problems such as an increase in cost due to an increase in circuits, a decrease in reliability, and a malfunction of an additional circuit due to noise or the like.

An object of the present invention is to provide a controller for a power converter that can reduce the switching frequency of the self-extinguishing element with a simple circuit configuration when the temperature of the self-extinguishing element of the power converter rises.

[Means for solving problems]

According to the present invention, the object is to hold a plurality of pulse pattern data having different switching frequencies in the storage means, and to store predetermined data from the storage means according to the temperature of the self-extinguishing element detected by the temperature detection means. This is achieved by selectively reading and switching the self-extinguishing element with the read data. The pulse pattern data having different switching frequencies may be set in advance in consideration of the minimum pulse width and the maximum allowable frequency.

[Work]

The temperature detecting means for detecting the temperature of the self-extinguishing element outputs a signal corresponding to the temperature of the self-extinguishing element. A microcontroller, which is a pulse pattern generator for control, selects pulse pattern data according to the output of the temperature detecting means. The control device of the power converter according to the present invention, when the temperature of the self-extinguishing element is high, since the selection of pulse pattern data having a low switching frequency, it is possible to reduce the switching loss of the self-extinguishing element, It is possible to prevent an excessive temperature rise of the self-extinguishing element without requiring an additional circuit such as a maximum allowable frequency setting circuit or a frequency comparison circuit as in the prior art.

〔Example〕

Hereinafter, a control device for a power converter according to the present invention will be described in detail with reference to the illustrated embodiments.

FIG. 1 is an embodiment of the present invention, in which 1 is a DC power supply, 2 is an input terminal for a frequency command ▲ ω ^* ₁ ▼, 3 is an input terminal for a phase command θ ^* , 4 is a DC reactor, 5 is GTO
Current source inverter main circuit consisting of self-extinguishing elements such as
Is a temperature sensor as means for detecting the temperature of the self-extinguishing element, 7 is an induction motor serving as a load of the power converter, 8 is a signal line for controlling switching of the self-extinguishing element, and 10 is a control pulse pattern generator. Is a one-chip micro computer (hereinafter referred to as a microcontroller).

The microcontroller 10 also includes an input port 101 for fetching various control commands, an internal bus 102, a ROM 1 for storing programs, pulse pattern data tables, and the like.
03, RAM 104 used as a temporary storage or register, ALU 105 for executing operations, output port 106, event setting register 107 for setting the event necessary to output a predetermined pulse pattern (event) to output port 106, Time setting register that sets the time when the business is enabled
108, a holding register 109 for connecting and holding the contents of these two setting registers 107, 108, an associative memory 110 in which some sets of setting data set in the holding register 109 are sequentially stored in a cycle, and an actual time is output. Timer 111,
The time set by the timer 111 is compared with the set time contents in the associative memory 110, and a comparison unit 112 that generates an output when they match, and a set event upon receiving a trigger from the comparison unit 112 is output port 106. An output execution controller 113 for controlling the output of the temperature sensor, an analog input port 114 for taking in a signal from the temperature sensor 6, an A / D converter 115 for converting a signal from the analog port 114 into a digital signal, and the like.

Next, the operation of this embodiment will be described.

FIG. 2 is a schematic flow chart of the event calculation processing program F1000 for obtaining the pulse pattern (event) generated at the output port 106 and the time for changing the pulse. First, in process F1100, the frequency command ▲ ω ^* ₁ ▼ and the phase command θ ^* are read from the input port 101. The frequency command ▲ ω ^* ₁ ▼ and the phase command θ ^* are usually obtained from a speed command device (not shown) for the induction motor 7 that is a load, but when calculating inside the microcontroller 10, this processing F110
It is not necessary to read the input port 101 at 0. Next, this frequency command ▲ ω ^* ₁ ▼ is integrated every fixed time Δt ₁ , and added with the phase command θ ^* to obtain the total phase θ _T in the process F1200.
Next, in the total phase θ _T obtained this time, which one of the plurality of self-extinguishing elements forming the inverter main circuit should be turned on or off, that is, the total phase θ _T
Which pulse pattern (actual image) should be output is calculated in process F1300. Next, processing F1400 for reading the output T of the temperature sensor 6 from the analog input port 114 is executed.
In process F1500, a process of selecting a pulse pattern time table to be referred to according to the output T of the temperature sensor 6 obtained in process 1400 is performed. In this process, the output T of the temperature sensor 6
Indicates that the higher the temperature of the self-extinguishing element is, the longer the time for one round, that is, the data of the pulse pattern having the lower switching frequency of the self-extinguishing element is selected. next,
Processing F1600 is executed which refers to the time until the pulse is changed according to the total phase θ _T from the pulse pattern time table selected in processing F1500. Further, depending on the output T of the temperature sensor 6, the next event calculation processing program F1000
And the processing to set the time until the event setting processing program F2000, which will be described later, is started in the timer for interrupt F1700
To execute.

By the above processing, the event contents and event change time set in the event setting register 107 and the time setting register 108 are obtained.

Next, a process for setting the event contents and the event change time thus obtained in the associative memory 110 for controlling the output port will be described with the event setting processing program F2000 shown in FIG.

First, in process F2100, it is determined whether or not the event content and event change time have been set for all of the plurality of self-extinguishing elements in the inverter main circuit 5, and if the determination result is NO, process F2
Execute the corresponding event content setting in 200, and further process F2300
Then, the event change time is set and the process ends.

The event calculation processing program F1000 and the event setting processing program F2000 described above are activated in order of F1000 and F2000 for each timer interrupt in synchronization with the timer interrupt generated at every predetermined time set in the timer in the process 1700. When the event setting processing program F2000 is completed, the associative memory 110 of the microcontroller 10 and the execution controller 113 are output ports.
ALU10 of the microcontroller 10 because it controls 106
The main processor section including 5 is released from the output processing and can execute the next event calculation processing program and the like.

Based on the result of the event setting processing program F2000, the self-extinguishing element in the inverter main circuit 5 is controlled by the associative memory 110 in the microcontroller 10 and the output port 106 executed by the execution controller 113 via the signal line 8. Alternatively, ON / OFF switching control is performed via a pulse amplifier (not shown) to supply three-phase AC power to the induction motor 7 as a load.

FIG. 4 shows an example of a pulse pattern train showing an on / off signal for one self-extinguishing element output from the output port 106. In this figure, when the signal is “1”, the self-extinguishing element is on. , When the signal is "0", the self-extinguishing element is off. Further, the pulse pattern trains (a) and (b) respectively show the case where the output of the temperature sensor 6 is low and the case where the temperature of the self-extinguishing element is high, and the event setting processing program 2000 is started for each case. The timing of the operation is indicated by an arrow.

Thus, in the embodiment of the present invention shown in FIG.
When the event calculation processing program F1000 shown in FIG. 2 is executed, the switching frequency of the self-extinguishing element is directly increased or decreased by selecting the pulse pattern time table to be referred to according to the state of the output T of the temperature sensor 6. You can Therefore, when the temperature of the self-extinguishing element rises, it is possible to suppress the temperature rise of the self-extinguishing element by selecting the pulse pattern time table so as to reduce the switching frequency of the self-extinguishing element.

If the temperature of the self-extinguishing element rises excessively,
By preparing in advance a pulse pattern time table for turning off all the self-extinguishing elements and selecting this table, it is possible to prevent permanent destruction due to abnormal heat generation of the self-extinguishing element. .

The temperature sensor 6 may be directly attached to the self-extinguishing element to directly detect the temperature of the self-extinguishing element, or may be provided around the self-extinguishing element to indirectly detect the temperature. . In addition, the temperature of the self-extinguishing element predicted from the input current value to the inverter main circuit 5 or the number of times of starting the induction motor 7, which is a load, is used as the output T of the temperature sensor 6 without using a temperature sensor that directly detects the temperature. May be used instead of.

〔The invention's effect〕

As described above, according to the present invention, a plurality of pulse pattern time tables are prepared, and the switching frequency of the self-extinguishing element can be changed only by selecting the table according to the temperature of the self-extinguishing element. Therefore, it is possible to reduce the switching loss when the temperature of the self-extinguishing element rises without the need for an additional circuit, and to provide a highly reliable power converter controller with a simple circuit configuration, compact size, and economy. can do. Further, according to the present invention, since the pulse pattern generator is configured to produce and output the pulse pattern in the microcontroller, the abnormality of the pulse pattern is equivalent to the abnormality of the semiconductor chip constituting the microcontroller. The abnormality can be self-diagnosed (for example, a watchdog timer) inside the microcontroller, and failure detection can be facilitated to further enhance the reliability of the entire system.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a control device for a power converter according to the present invention, FIGS. 2 and 3 are flow charts for explaining the operation of an embodiment of the present invention, and FIG. It is a figure which shows the example of the output waveform at the time of operation | movement of one Example of invention. 1 ... DC power supply, 2, 3 ... Command input terminal, 4 ... DC reactor, 5 ... Inverter main circuit, 6 ... Temperature sensor, 7 ... Induction motor, 8 ... Signal line, 10 ... Microcontroller, 101 ... Input port, 102 ... Internal bus,
103 ... ROM, 104 ... RAM, 105 ... ALU, 106 ... output port, 107 ... event setting register, 108 ... time setting register, 109 ... holding register, 110 ... associative memory, 111
...... Timer, 112 …… Comparison unit, 113 …… Execution controller, 114 …… Analog input port, 115 …… A / D converter.

Front Page Continuation (72) Inventor Kazuhiro Sakata 1070 Ige, Katsuta-shi, Ibaraki Hitachi, Ltd. Mito Plant (72) Inventor Masaro Nakazato 1070 Ige, Katsuta-shi, Ibaraki Hitachi Ltd. Mito Plant, Ltd. (56) References JP-A-60-245494 (JP, A)

Claims (3)

[Claims] 1. A self-arc-extinguishing element that constitutes an inverter main circuit, and a pulse pattern generator that is connected to the self-arc-extinguishing element to turn the self-arc-extinguishing element on or off directly or through a pulse amplifier circuit. In a power converter consisting of
Temperature detection means for detecting at least one of the temperature of the self-extinguishing element and the ambient temperature, storage means for holding a plurality of pulse pattern time tables, and the storage according to the detection value of the temperature detection means. Data selecting means for selecting predetermined pulse pattern data from a plurality of pulse pattern time tables held in the means, wherein the storage means and the data selecting means are provided in the pulse pattern generating device. Control device for power converter. 2. A means for selecting pulse pattern data for turning off the self-extinguishing element from the storage means when the detected value of the temperature detecting means exceeds a predetermined value is provided in the pulse pattern generator. The control device for a power converter according to claim 1, wherein the control device is a power converter. 3. A temperature value of a self-extinguishing element obtained by predicting from an input current value to the inverter main circuit or the number of times of starting a load connected to the inverter main circuit, instead of the detection value of the temperature detecting means. The control device for a power converter according to claim 1 or 2, characterized in that: