JPS59136089A - Normal and reverse switching method of digital thyristor leonard - Google Patents

Abstract

PURPOSE:To switch positive/reverse side thyristor converters by detecting the interruption time of the armature current of a motor by providing a current continuation/interruption detector and applying a counterelectromotive force via a microprocessor, thereby obtaining an accurate counter electromotive force value. CONSTITUTION:Positive/reverse side thyristor converters 2, 3 are connected to a DC motor 5, an armature current is applied from a shunt 4 to an A/D converter 7, and a voltage is applied to an A/D conveter 11, inputted to a bus 9, a normal/reverse switch 17 is controlled by a microprocessor 13, thereby switching the converters 2, 3. At this time a current continuation/interruption detector 20 is provided in the shunt 4 to detect the interruption of the armature current, the terminal voltage, i.e., the counterelectromotive voltage of the motor 5 is applied at a timing that the current is zero, and the switch 17 is controlled by the counterelectromotive voltage value. Accordingly, expected firing angle can be accurately calculated by the accurate counterelectromotive voltage value, thereby preventing the excess armature current.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an all-digital thyristor Leonard control device using a microprocessor, and in particular to a thyristor Leonard control device on the active side to a thyristor converter on the standby side. Regarding the method.

[Prior art]

Figure 1 shows a state in which the positive side thyristor converter Sl operates to rotate the DC motor M in the forward direction, and after a certain period of time in this state, the armature current changes to a state of 8-0, and as shown in Figure 2. The reverse thyristor converter S2 shown in FIG. 1 operates to enter a state of reverse conversion. Figure 3 shows the operation time chart for the above two states.
2 (positive) is flowing continuously. Next, the output voltage VTH (positive) of the positive side SiRisk converter is decreased, and the output voltage VTH (positive) is brought into an intermittent state. Completely 1. After (positive) becomes zero, the firing pulse of the positive thyristor is stopped to stop the output of this thyristor converter. Next, a firing pulse is applied to the opposite thyristor converter to utilize the output of the opposite thyristor converter. In order to determine the ignition phase at this time, the back electromotive force EMF of the DC motor is required. Tore is
In the initial operation state of the inverse conversion side thyristor in Fig. 3,
By starting the VTR (reverse) with a value higher than the back electromotive force EMF, an excessive 1. This is to prevent the (reverse) current from flowing to the DC motor M, thereby preventing deterioration of the DC motor and the Cyrisk converter.

FIG. 4 shows the configuration of a microprocessor-based all-digital Zairis Leonard control system using the conventional method for detecting the back electromotive force EMF of the DC motor. A three-phase AC power supply 1 is connected to the input sides of a positive three-phase full-wave thyristor converter 2 and a reverse three-phase full-wave thyristor converter 3. These forward and reverse three-phase full-wave Cyrisk converters 2
, 3 are connected to a DC motor 5 via a shunt resistor 4. The voltage on both sides of the shunt resistor 4 is inputted to an A/D converter 7 via a filter 6, and this A/D converter 7 outputs a current value 8 of the DC motor 5 to a common bus 9. The voltage across the DC motor 5 is input to the A/D converter 11 via the filter 10, and the A/D converter 11 outputs the terminal voltage value 12 of the DC motor to the common bus 9.

A microprocessor 13 and a memory 14 storing an execution program for the microprocessor 13 are connected to the common bus 9. The firing angle command 15 from the microprocessor 14 is input to the gate pulse generator 16 via the common bus 9, and the output signal of the gate pulse generator 16 is switched to the forward and reverse three-phase via the forward/reverse switch 17. The signal is input to either the gate of the full-wave thyristor converter 2 or 3.

The gate pulse generator 16 generates gate pulses for the positive three-phase full-wave thyrisk converter 2 and the reverse three-phase full-wave thyrisk converter 3. In addition, the forward/reverse switch 17 has a digital output 18.
The forward/reverse switching command 19 from the microprocessor 13 is input to this digital output 18 through the common bus 9.

Incidentally, the operation of the forward/reverse switch 17, that is, the operation of the digital output 18, is based on the calculation result of the microprocessor 13. In this calculation, VTR (reverse) > EMF
・・・・・・・・・・・・(1) VTH(
Reverse) = 1.35 It is necessary to satisfy both equations of EACCO8α - (2). However, EMF represents the back electromotive voltage (volts) of the DC motor 5, EAc represents the AC input effective voltage (volts), and α represents the control delay angle (degrees).

If the condition of equation (1) is not satisfied and VTH (inverse) < EM
F, the current of the DC motor 5 becomes 1. (The opposite) results in an excessive value. Further, when Vtu>EMF, problems arise such as the time required to switch the thyristor converter from positive to reverse.

In the prior art forward/reverse switching method of digital thyristor Leonard shown in FIG. 2, when detecting EMF,
A method is adopted in which the data is input to the microprocessor 13 using a filter 10 and an A/D converter 11. However, in such a conventional system, as shown in FIG.
When the armature current is continuous, it is possible to detect a voltage almost equal to the EMF, but as shown in Fig. It has the characteristic of detecting high EMF. Additionally, in general, in the conventional EMF detection method described above, during forward conversion when power flows from the three-phase AC power source 1 to the DC motor 5, the EMF is normally detected even when the true value is passed; During reverse conversion flowing through the AC power supply 1, there is a tendency for the EMF to be detected at a low level. Therefore, in any case, the conventional EMF detection method cannot detect the true back electromotive force EMF of the DC motor 5, so the standby voltage of the standby side converter cannot be accurately calculated, and as described above. There was a drawback that caused some inconvenience.

[Purpose of the invention]

An object of the present invention is to provide a forward/reverse switching method for a digital thyristor Leonard that eliminates the above-mentioned drawbacks, shortens the forward/reverse switching time, and does not cause excessive armature current to flow.

[Summary of the invention]

The present invention provides a thyristor Leonard control device that uses a microprocessor to switch a forward and reverse thyristor converter by non-circulating current control, in which the back electromotive voltage of a DC motor is converted to the output current of the thyristor converter (or The above object is achieved by capturing the back electromotive voltage value at the timing when the armature current (armature current) is zero, and using this back electromotive force value to determine an accurate initial switching firing angle of the timing side thyristor converter.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings, using the same reference numerals for the same parts as in the conventional example. FIG. 7 is a block diagram showing an embodiment of a digital thyristor Leonard control device to which the digital thyristor Leonard forward/reverse switching method of the present invention is applied. A three-phase AC power supply 1 is connected to the input sides of positive and reverse three-phase full-wave thyristor converters 2 and 3, and a shunt resistor 4 is connected to the output sides of these positive and reverse three-phase full-wave thyristor converters 2 and 3. It is connected to the DC motor 5 via the DC motor 5. or,.

The gates of the three-phase full-wave thyristor converters 2 and 3 on the forward and reverse sides are connected to the gate pulse generator 16 via a forward/reverse switch 17, and the output signal of the digital output 18 is input to the forward/reverse switch 17. ing. A microprocessor 13 and a memory 14 are connected to the common bus 9.
A firing angle command 15 and a forward/reverse switching command 19 are input to a gate pulse generator 16 and a forward/reverse switch 17 through a common bus 9, respectively.

The voltage across the DC motor 5 is directly input to an A/D converter 11, which outputs a DC motor terminal voltage value 12 to the common bus 9. The voltage across the 7 Yant resistor 4 is input to the current continuity detection device 20, where it becomes an intermittent signal 21 and is input to the digital human power 22, and the output side of the digital human power 22 is connected to the common bus 9. .

The voltage value across the shunt resistor 4 is changed to A via the filter 6.
/]) is input to the converter 7, and the A/D converter 7 outputs the current value 8 of the DC motor 5 to the common bus 9. As described above, the digital thyristor Leonard control device of this embodiment has almost the same configuration as that of the conventional example, but the difference from the conventional example is that the DC current of the motor 5 (same as the armature current) 1 A current continuity/disconnection detection device 20 is added to detect continuity/disconnection of the DC motor 5, and the voltage across the DC motor 5 is directly input to the A/D converter 11.

Next, the operation of this embodiment will be explained. To summarize the operation of this embodiment, when the armature current
The back electromotive force EMF of the DC motor 5 is generated through the /Di converter 11.
is detected by the microprocessor 12. FIG. 8 shows the operation time chart. That is, the current connection/disconnection detection device 20 detects the point in time when the armature current (or the output current of the forward and reverse side risk converter) 1.19 is disconnected, and at this timing, the terminal voltage of the DC motor 5 is detected by the A/D. An increasing operation is performed through the converter 11. It should be noted that when the current continuity/disconnection detection device 20 detects ``1° disconnection'' at a high level, it is the timing to detect the terminal voltage of the motor 5.There are two methods of detection as shown below.

FIG. 9(a) is a flowchart showing one method. This is step 101 and digital human power 2 in Figure 7
In this method, it is checked whether the output signal No. 2, that is, the current interruption signal, is 1 or not, and if it is 1, the back electromotive force EMF of the DC motor 5 is inputted in step 102.

FIG. 9(B) shows a system in which an interrupt occurs when the armature current (2) is cut off, and at this time, the back electromotive force EMF is input in step 101. The path shown by the dotted line connecting the output side of the current continuity detection device 20 to the microprocessor 13 in FIG. 7 is the above-mentioned interrupt line.

According to this embodiment, the current disconnection detection device 20 detects disconnection of the armature current of the DC motor, and when the current disconnection occurs, the microprocessor 13 detects the terminal voltage of the DC motor 5, that is, the back electromotive force EMF. By inputting the signal through the A/D converter 11, accurate EMF can be detected as shown in FIG.

Therefore, the microprocessor 13 can accurately calculate the timing firing angle of the timing side thyristor converter (for example, when switching from positive to reverse, the reverse side thyristor converter 3 becomes the timing side) using this accurate EMF. This reduces forward/reverse switching time, and prevents excessive armature current from starting when the thyristor converter starts operating.
, can be prevented from flowing, thereby improving the durability and reliability of the device.

〔Effect of the invention〕

As described above, according to the forward/reverse switching method of the digital thyristor Leonard of the present invention, the back electromotive voltage of the DC motor is captured at the timing when the output current of the forward and reverse side thyristor converters is zero, and this back electromotive voltage is used. By calculating the timing firing angle of the timing side risk converter, it is possible to shorten the forward/reverse switching time and prevent excessive armature current from flowing.

[Brief explanation of the drawing]

1 and 2 are explanatory diagrams showing a forward/reverse switching method when driving a DC motor using a forward/reverse sirisk converter, and FIG. 3 is an operation time chart diagram of FIGS. 1 and 2.
Fig. 4 is a configuration diagram showing an example of a digital thyristor Leonard control device using the conventional forward/reverse switching method, and Fig. 5 is an operating waveform diagram of each part of the device shown in Fig. 4 when the armature current is continuous. FIG. 6 is an operating waveform diagram of each part of the device shown in FIG. 4 when the armature current is intermittent, and FIG. 7 is an illustration of a digital thyristor Leonard control device to which the digital thyristor Leonard forward/reverse switching method of the present invention is applied. A configuration diagram showing the embodiment, FIG. 8 is an operation time chart of the embodiment shown in FIG. 7, and FIG. 9 (5) and IB) show the back electromotive force of the DC motor shown in FIG. 7. FIG. 3 is a flowchart illustrating an example of a method for capturing. 1... AC power supply, 2... Positive side three-phase full-wave thyristor converter, 3... Reverse-side three-phase full-wave thyristor converter, 5...
・DC motor, 11... A/D converter, 13... Microprocessor, 16... Gate pulse generator, 1
7... Forward/reverse switch, 20... Current connection detector, 21
... Digi 1 Ward 7 Mekaya 8 Ro41- Kayata Usu (A)

Claims (1)

[Claims] 1. It has positive and reverse thyristor converters connected to an AC power source and a DC motor connected to these positive and reverse thyristor converters, and has a positive and reverse thyristor converter. Switch and
In a digital thyristor Leonard control device that uses a microprocessor to control a DC motor, the microprocessor captures the back electromotive force of the DC motor during the period when the output current of the operating thyristor converter to the DC motor is zero, and this A method for forward/reverse switching of a digital thyristor Leonard, characterized in that the switching initial firing angle of a standby side thyristor converter is determined using a back electromotive voltage, and the standby side thyristor converter is operated. 2. Based on the detection timing of the current continuity detector, which takes in the output current of the Cyrisk converter and detects when this current is intermittent, the microprocessor directly detects the terminal voltage of the DC motor via the A/D converter. 2. A forward/reverse switching method for a digital thyristor Leonard according to claim 1, characterized in that the forward/reverse switching method of a digital thyristor Leonard is carried out in the following manner.