JPH03183389A - Controller for induction motor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention converts AC power output into DC using a phase-controlled rectifier capable of bidirectional power conversion, and further converts this DC into AC using an inverter. The present invention relates to a control device for an induction machine that converts the data into an induction machine to drive the induction machine.

(Prior art) When controlling the edible speed of an induction machine using a PWM inverter,
It is common practice to control a DC power supply to a constant voltage.

In addition, the induction machine rotates and rotates due to acceleration and deceleration, etc. When used in both L modes, the DC power supply is not just a rectifier;
It is required to have power regeneration capability.

FIG. 7 shows a conventional control circuit for such a PWM inverter. In FIG. 7, 1 is a phase control rectifier that rectifies the AC power output to obtain a constant voltage DC output, 2 is a smoothing filter that smoothes the DC voltage, and 3
4 is an induction machine driven by the output of the inverter 3; 5 is a speed sensor that detects the speed of the induction machine 4; is a speed control circuit that roughly controls the speed of the induction machine, 7 is a control circuit for the inverter 3, 8 is a constant voltage control circuit for the DC circuit, 9 is a current control circuit for the phase control rectifier 1, and 10 is also a phase control circuit. .

In the normal case, the inverter 3 and the phase-controlled rectifier 1 are controlled individually. That is, the phase control rectifier] detects its DC output voltage Vt'llK, and is controlled by the voltage control circuit 8 to reach a predetermined target value VREP. This voltage control circuit 8 has a current J! The quasi I REF is output, and the current I FBK of the phase control rectifier 1 is controlled by the current control circuit 9.
is controlled. The current control circuit 9 outputs the phase reference α of the phase control rectifier 1, and based on this, the current control circuit 10
controls the gate pulses G and P of the phase controlled rectifier 1.

On the other hand, the input/motor 3 is controlled by a speed control circuit 6 so that the speed SFnK of the induction machine 4 detected by the speed sensor 5 becomes a predetermined target speed. The output of the speed control circuit 6 is input to an inverter control circuit 7, and the inverter control circuit 7 controls the torque generated by the induction machine 4 by controlling the energization of the inverter 3. In this case, the inverter control circuit 7 controls the primary current (111PK) of the induction machine 4.
If the speed control circuit 6 is constructed using a vector system that detects and controls the torque and separates it into a torque component and a magnetic flux component, the output of the speed control circuit 6 is the reference value T IIE of the torque generated by the induction machine 4.
It becomes F. Inverter li! The Iga circuit 7 separates and controls the primary current of the induction machine 3 into a torque component and an excitation component based on the torque reference value TゎF.

On the other hand, in a system in which multiple induction machines are individually controlled by PWM inverters, each inverter is generally not provided with a DC power supply, and low voltage DC power is supplied to all inverters by one common DC constant voltage power supply. The voltage of each induction machine is controlled by an inverter.

FIG. 8 shows a control circuit for a PWM control inverter using such a common DC power supply system. In FIG. 8, the same parts as in FIG. 7 are given the same symbols and their explanations are omitted, and only the point of 5° C. will be described here. In Fig. 8, two inverters 3A and 3B are used as an induction motor 4A, respectively.
4B, and these inverters 3A, 3
B is controlled so that the speed signals detected by the speed sensors 5A and 5B become the target speed MISahp.

(Problem to be Solved by the Invention) The control device for an induction machine configured as described above has a problem in that the DC voltage There was a problem with the control response, and there was a drawback that overvoltage and undervoltage of DC 7I5 were generated.

Generally phase 1. In the phase controlled rectifier 'Pi1, a Zyristor is often used as an element constituting the main circuit, and the current control response of the phase controlled rectifier is significantly slower than that of the inverter 3. In particular, when the induction machine 4 suddenly decelerates and the inverter 3 regenerates power to the DC circuit, the phase control rectifier 1 using the anti-parallel Zyristor has a delay interval of several o+sec to switch from power to regeneration. During this time, the smoothing filter 2 was overcharged by the output power from the inverter 3, resulting in an overvoltage problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide a control device for an induction machine that does not cause overvoltage or undervoltage to occur in a DC circuit even when the induction machine is suddenly accelerated or decelerated.

[Structure of the Invention] (Means for Solving the Problem) In order to achieve the above object, the first invention converts alternating current into direct current using a phase-controlled rectifier capable of bidirectional power conversion nJ, and converts the direct current of this rectifier into direct current. In a control device for an induction machine in which the output is converted to alternating current by an inverter to drive the induction machine, a calculation means for calculating the output power of the inverter from the torque generated by the front grip induction machine or a reference value of the generated torque and the rotation speed. , voltage control means for controlling the output DC voltage of the phase control rectifier, current control means for controlling the output DC current or input current of the phase control rectifier, and the output power of the inverter and the output of the voltage control means. and an addition means for adding the values and using the result as a current reference for the phase control rectifier.

In the second invention, instead of the calculation means constituting the first invention, the primary current of the induction machine is separated into a torque component and an excitation component, and the torque current component or the reference value of the torque current component and the terminal voltage of the induction machine are calculated. This system is provided with calculation means for determining the output power of the inverter from the following.

In the third invention, alternating current is converted into direct current by a phase control rectifier capable of bidirectional power conversion, and the direct current output of this rectifier is converted into alternating current by a plurality of inverters to drive an induction machine corresponding to each inverter. In the induction machine control device as described above, the output power of each inverter is calculated from the torque generated by each induction machine or the reference value of the generated torque and the rotation speed. means, voltage control means for controlling the DC output voltage of the phase control rectifier, current control means for controlling the DC output current or input current of the phase control rectifier, and the output power of each inverter determined by the calculation means. and an output of the DC control means, and the sum is added to the output of the DC control means, and the sum is used as a current reference for the phase control rectifier.

In the fourth invention, instead of the calculation means constituting the third invention, the primary current of the induction machine is separated into a torque component and an excitation component, and the torque current component or the reference value of the torque current component and the terminal voltage of the induction machine are This system is provided with calculation means for determining the output power of the inverter from the following.

(Operation) Therefore, in the induction machine control device configured as in the first and second inventions, the output power of the inverter proportional to the input terminal of the phase control rectifier is controlled by the voltage control means of the phase control rectifier. Since the current reference of the phase control rectifier is controlled by feedforward by adding it to the output,
Even if the induction machine undergoes sudden over-deceleration, the responsiveness of voltage control is improved, making it possible to reduce fluctuations in DC voltage.

Furthermore, even in a control device that supplies the DC output of a phase-controlled rectifier to a plurality of inverters and independently controls the speed of the induction machine corresponding to each inverter, as in the third and fourth inventions, Since the total output power is added to the output of the DC control means to perform feedforward control of the current reference of the A-phase control rectifier, the responsiveness of voltage control is improved even if the induction machine suddenly accelerates or decelerates. , it becomes possible to reduce changes in DC voltage.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of the induction motor control device according to the present invention. Parts that are the same as those in FIG. . In the first embodiment, as shown in FIG. 1, the torque reference TAF is output from the speed control circuit 6 of the inverter control system.
, , by the magnetic flux component to obtain a torque component current IIq, and a divider 11 that supplies this to the inverter control circuit 7;
Torque distribution tM, I 1 output from this divider 11
q is multiplied by the terminal voltage VM of the induction machine 3 to obtain the output power P of the inverter, and a multiplier 12 is provided for adding this to the output of the voltage control circuit 8 of the phase control rectifier control system.

In the induction machine control device configured as described above, when the deviation between the speed reference S REF and the speed S2.3 of the induction machine 4 is given to the speed control circuit 6, the torque references TR, F are transmitted from the speed control circuit 6. is obtained. This torque standard T82
．． is input to the divider 11, the torque reference T. The torque current is determined by dividing F by the magnetic flux component Φ.1. is determined and added to the inverter control circuit 7 as well as to the multiplier 12, where the torque trace reference TREF of the induction machine 4 is multiplied by the terminal voltage VM to determine the output power P of the inverter.

This output power P is further added to the output of the voltage control circuit 8 to become the current base 41RFP of the phase control rectifier 1.

Therefore, since the input terminal IFBK of the phase control rectifier 1 is proportional to the output power of the inverter 3, the power and regeneration state of the induction machine 4 are determined based on the current reference I REP obtained from the torque current reference 11Q. The DC circuit 7 performs feedforward control of the pressure, thereby improving the responsiveness of voltage control and reducing fluctuations in the DC voltage.

FIG. 2 shows a second embodiment of the present invention, and the same parts as those in FIG. 7 are given the same symbols, and the explanation thereof will be omitted, and the previous points will be described here.

In the second embodiment, as shown in FIG. 2, the output of the speed control circuit 6 of the inverter control system and the speed of the induction machine 4 detected by the speed sensor 5 are multiplied by the multiplier 12 to obtain the output of the inverter 3. The power P is determined and the output power P is added to the current base /$IR1:P output from the voltage control circuit 8 of the control system of the phase control rectifier.

Therefore, even with this configuration, the voltage of the DC circuit is controlled feedforward in the same way as described above, so the responsiveness of voltage control can be improved and fluctuations in DC voltage can be reduced. This shows the third embodiment of the present invention, and the same parts as those in FIG. The control system is omitted from the illustration.

In FIG. 3, the difference from FIG. 1 is that the DC constant voltage circuit is used as a J+- supply source, and a plurality of inverters 3A are used.

3B and the induction machines 4A and 4B driven by the respective inverters 3A and 3B are connected to each other and their speeds are controlled independently. This direct current (in the case of the power supply method, calculate the output power PA, PB for each inverter,
The adder circuit 13 calculates the sum P of the output powers PA and Pr3, and adds this sum P to the current 2X$IRgp output from the voltage control circuit 8 of the phase nil in rectifier control system.

Since the sum P of the output powers PA, P of each inverter is proportional to the sum of the currents output from the DC circuit, the same effect as described above can be obtained by adding this to the current reference I 1F.

FIG. 4 shows a fourth embodiment of the present invention, in which the same parts as in FIG. 3 are given the same symbols and their explanation will be omitted, and only the different points will be described here. In addition, in FIG. 4, the control system on the inverter 3A side is omitted.

The difference between FIG. 4 and FIG. 3 is that when the plurality of inverters 3A and 3B have different output capacities, the rated output capacities KWA and kW B are calculated for each device in order to obtain the output power PA and PR for each inverter. is multiplied by [multiplier]4. As a result, the total output power P is proportional to the total current output to the DC circuit even if the output capacity of the inverter 3 connected to the DC circuit is different, so this is used as the current reference for the phase control rectifier. By adding , the same effect as described above can be obtained.

FIG. 5 shows a fifth embodiment of the present invention. Parts that are the same as those in FIG. 2 are given the same symbols and their explanation will be omitted, and only the most important points will be described here. Note that the control system on the inverter 3A side is omitted in FIG.

In the fifth embodiment, the embodiment of FIG.
, 3B's speed control circuits 6A, 6B.
Obtain the output power PA and PB of δB. By adding these output powers PA, P, and l in the adder circuit 13 and adding the sum P to the current reference ■REP of the phase control rectifier 1, the same as in the embodiment described above can be obtained. It is possible to obtain the following effects.

FIG. 6 shows a sixth embodiment of the present invention. Parts that are the same as those in FIG. 5 are given the same symbols, and the explanation thereof will be omitted, and only the different points will be described here. In addition, in FIG. 6, the control system on the inverter 3A side is omitted.

In Fig. 6, the difference from Fig. 5 is the inverter 3A.
If 3B is the older output capacitance, the output capacitance KWA of each inverter is the output of the multiplier 12.

The point is that K W s is multiplied by the multiplier 14 to obtain the output power pA, p for each device. As a result, the total power P becomes equal to the amount of power input and output from the four-stream common power supply, and the same effects as described above can be obtained.

In each of the embodiments shown in FIGS. 3 to 6, the case where two inverters are connected to a DC (current-carrying power source) is used as an example, but the present invention is not limited to two inverters, but can also be connected to three or more inverters. However, it can be implemented in the same manner as described above.

In addition, in each of the above-described embodiments, the torque reference TREF% or the torque current is calculated by 11 degrees, or the torque current is calculated from the torque detection value detected at the time of failure, or the torque current detected from the primary current detection value of the induction machine 4. Of course, this is a good thing.

[Effects of the Invention] As described above, according to the present invention, the current reference of the phase control rectifier is controlled by feedforward by adding an innovative output wheel to the voltage control four paths of the phase control rectifier control system. Therefore, it is possible to provide an induction machine control device that does not generate overvoltage or undervoltage in the DC constant voltage circuit even when the induction machine is suddenly accelerated or decelerated.

[Brief explanation of drawings]

1 to 6 are circuit configuration diagrams showing first to sixth embodiments of an induction motor control device according to the present invention, and FIGS. 7 and 8 are circuit diagrams showing different conventional induction motor control devices, respectively. FIG. 1... Phase control rectifier, 2... 1 self-waste filter,
3...Inverter, 4...Induction machine, 5...Speed sensor, 6...Speed control circuit, 7...Innoku Ichiyo control circuit, 8...Voltage control circuit, 9... - Current control circuit, 10... Phase control circuit, 11... Divider, L2.
14... Multiplier, 13... Adder.

Claims (4)

[Claims] (1) In the control device for an induction machine, which converts alternating current into direct current using a phase control rectifier capable of bidirectional power conversion, and drives the induction machine by converting the direct current output of the rectifier into alternating current using an inverter. calculation means for calculating the output power of the inverter from the torque generated by the induction machine or a reference value of the generated torque and the rotation speed; voltage control means for controlling the DC output voltage of the phase control rectifier; and the DC output current of the phase control rectifier. or current control means for controlling the input current;
A control device for an induction machine, comprising: an addition means that adds the output power of the inverter and the output of the voltage control means, and uses the result as a current reference for the phase control rectifier. (2) In the control device for an induction machine, which converts alternating current into direct current using a phase control rectifier capable of bidirectional power conversion, and drives the induction machine by converting the direct current output of the rectifier into alternating current using an inverter. a calculation means that separates the primary current of the induction machine into a torque component and an excitation component and calculates the output power of the inverter based on the torque current component or a reference value of the torque current component and the terminal voltage of the induction machine; and the phase control rectifier. voltage control means for controlling the DC output voltage of the phase control rectifier, current control means for controlling the DC output current or input current of the phase control rectifier, and adding the output power of the inverter and the output of the voltage control means to determine the phase 1. A control device for an induction machine, comprising: addition means that uses a current reference of a control rectifier. (3) AC is converted to DC using a phase-controlled rectifier that can convert power in both directions, and the DC output of this rectifier is converted to AC using multiple inverters to drive the induction machine corresponding to each inverter. In the induction machine control device, a calculation means for calculating the output power of each inverter from the generated torque or a reference value of the generated torque and the rotation speed of each induction machine, and a voltage control means for controlling the DC output voltage of the phase control rectifier. , current control means for controlling the DC output current or input current of the phase control rectifier, and the phase control by adding the sum of the output power of each inverter obtained by the calculation means and the output of the DC control means. 1. A control device for an induction machine, comprising: addition means that uses a current as a reference for a rectifier. (4) AC is converted to DC using a phase-controlled rectifier capable of bidirectional power conversion, and the DC output of this rectifier is converted to AC using multiple inverters to drive the induction machine corresponding to each inverter. In the induction machine control device, the primary current of each of the induction machines is separated into a torque component and an excitation component, and the output power of each of the inverters is determined based on the torque current component or a reference value of the torque current component and the terminal voltage of the induction machine. a calculation means for calculating, a voltage control means for controlling the DC output voltage of the phase control rectifier, a current control means for controlling the DC output current or input current of the phase control rectifier, and a calculation means for each inverter calculated by the calculation means. A control device for an induction machine, comprising: adding means for adding the sum of output power and the output of the DC control means to use the sum as a current reference for the phase control rectifier.