JP2645159B2 - Induction machine control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention converts an AC power supply output to DC by a phase control rectifier capable of bidirectional power conversion, and further converts this DC to AC by an inverter. The present invention relates to a control device of an induction machine that drives an induction machine after conversion.

(Conventional technology) When controlling the induction machine with a PWM inverter at variable speed,
It is common to control a DC power supply to a constant voltage.
Further, when the induction machine is used in both powering and regeneration modes due to acceleration / deceleration or the like, the DC power supply is required to have not only a rectifier but also a power regeneration capability.

FIG. 7 shows a control circuit of such a conventional PWM inverter. In FIG. 7, 1 is a phase control rectifier having a regenerative ability to rectify an AC power supply output to obtain a constant voltage DC output, 2 is a smoothing filter for smoothing a DC voltage, and 3 is a smoothing filter 2 from the phase control rectifier 1. An inverter for converting a direct current input through the inverter to an alternating current;
An induction machine driven by the output of the motor, 5 a speed sensor for detecting the speed of the induction machine 4, 6 a speed control circuit for controlling the speed of the induction machine, 7 a control circuit for the inverter 3, and 8 a constant voltage for the DC circuit. A control circuit, 9 is a current control circuit of the phase control rectifier 1, and 10 is a phase control circuit.

In a normal case, the inverter 3 and the phase control rectifier 1 are individually controlled. That is, the phase control rectifier 1 detects the DC output voltage V _FBK, and is controlled by the voltage control circuit 8 so as to have a predetermined target value V _REF . The voltage control circuit 8 outputs a current reference I _REF , and the current control circuit 9 controls the current _IFBK of the phase control rectifier 1. The current control circuit 9 outputs the phase reference α of the phase control rectifier 1, and based on this, the phase control circuit 10 outputs the gate pulse of the phase control rectifier 1.
Control the GP. On the other hand, the inverter 3 is controlled by the speed control circuit 6 so that the speed S _FBK 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, which controls the energization of the inverter 3 to control the torque generated by the induction machine 4. In this case, the inverter control circuit 7 controls the primary current (I
_1IFK ), the output of the speed control circuit 6 is the reference value T _{REF of the} torque generated by the induction machine 4 if the vector system is configured to detect and control the torque component and the magnetic flux component.
Becomes The inverter control 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 _REF .

On the other hand, in a system in which a plurality of induction machines are individually controlled by a PWM inverter, generally, no DC power supply is provided for each inverter, 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 of such a common DC power supply type PWM control inverter. In FIG.
The same reference numerals are given to the same parts as those in the drawings, and the description thereof will be omitted.
Here, only different points will be described. In FIG. 8, two inverters 3A and 3B drive induction machines 4A and 4B, respectively, and these inverters 3A and 3B
Control is performed so that the speed signals detected at A and 5B become the target speed reference S _REF .

(Problem to be Solved by the Invention) In the control device for an induction machine configured as described above, when an operation is performed in which the direction of power of a DC circuit including a phase control rectifier is rapidly changed, a DC voltage is However, there is a problem in the control response of the above, and there is a drawback that an overvoltage or an undervoltage of the DC voltage is generated. In general, the thyristor is often used as an element constituting the main circuit in the phase control rectifier 1, and the current control response of the phase control rectifier 1 is much slower than the current control response of the inverter 3. In particular, the induction machine 4 suddenly decelerates,
When the inverter 3 regenerates power to the DC circuit, the phase control rectifier 1 using the anti-parallel thyristor has a delay time of several milliseconds for switching from power running to regeneration, during which time the smoothing filter is regenerated by the regenerative power from the inverter 3. 2 was overcharged, resulting in an overvoltage.

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

[Constitution of the Invention] (Means for Solving the Problems) In order to achieve the above object, in the first invention, alternating current is converted to direct current by a phase control rectifier capable of bidirectional power conversion, and the dc output of the rectifier is changed. In an induction machine control device that drives the induction machine by converting the AC power into an AC by an inverter, a calculating means for calculating the output power of the inverter from the generated torque of the 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 adding the output power of the inverter and the output of the voltage control means The phase control rectifier is provided with an adding means for setting a current reference.

In the second invention, the primary current of the induction machine is separated into a torque component and an excitation component instead of the arithmetic means constituting the first invention, and the torque current component or the reference value of the torque current component and the terminal voltage of the induction machine are obtained. And arithmetic means for calculating the output power of the inverter from the above.

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 the rectifier is converted into alternating current by a plurality of inverters to drive an induction machine corresponding to each inverter. In the control device for an induction machine as described above, a calculation means for obtaining the output power of each inverter from the generated torque of each of the induction machines or the reference value of the generated torque and the number of rotations, and controls the DC output voltage of the phase control rectifier. Voltage control means, current control means for controlling the DC output current or input current of the phase control rectifier, and adding the sum of the output powers of the respective inverters obtained by the calculation means and the output of the DC control means The phase control rectifier is provided with an adding means for setting a current reference.

In the fourth invention, the primary current of the induction machine is separated into a torque component and an excitation component instead of the arithmetic means constituting the third invention, and the torque current component or the reference value of the torque current component and the terminal voltage of the induction machine are obtained. And arithmetic means for calculating the output power of the inverter from the above.

(Operation) Therefore, in the induction motor control device configured as in the first and second aspects, the output power of the inverter proportional to the input current of the phase control rectifier is controlled by the voltage control means of the phase control rectifier. Feed forward control of the current reference of the phase control rectifier by adding to the output improves the responsiveness of the voltage control even if the induction machine suddenly decelerates, reducing fluctuations in DC voltage. Becomes

Further, even in the control device that supplies the DC output of the phase control 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 sum of the output power is added to the output of the DC control means to control the current reference of the phase control rectifier in a feedforward manner, the responsiveness of the voltage control is improved even if the induction machine suddenly decelerates, and the DC control is improved. Voltage fluctuation can be reduced.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a first embodiment of a control device for an induction machine according to the present invention. The same parts as those in FIG. 7 are denoted by the same reference numerals, and the description thereof will be omitted. Only different points will be described here. . In the first embodiment, the torque reference T _AEF output from the speed control circuit 6 of the inverter control system as shown in FIG.
Was divided by magnetic flux component to obtain a torque current I _1q by a divider 11 to be provided to the inverter control circuit 7, the divider 11 the terminal voltage of the induction machine 3 to torque current I _1q output from V _M And a multiplier 12 for obtaining the output power P of the inverter by multiplying the output of the inverter and adding the output power P to the output of the voltage control circuit 8 of the phase control rectifier control system.

In the control device for an induction machine configured as described above, when a deviation between the speed reference S _REF and the speed S _FBK of the induction machine 4 is given to the speed control circuit 6, a torque reference T _REF is obtained from the speed control circuit 6. Can be If the torque reference T _REF is inputted to a divider 11, a torque current reference I _1q are determined by dividing the torque reference T _REF in magnetic flux component [Phi, applied to the multiplier 12 together applied to the inverter control circuit 7 , Where the induction machine 4
The output power P of the inverter is determined by multiplying the terminal voltage V _M to the torque reference T _REF of. This output power P is further added to the output of the voltage control circuit 8 to become the current reference I _REF of the phase control rectifier 1.

Therefore, since the input current _IFBK of the phase control rectifier 1 is proportional to the output power of the inverter 3, the power running of the induction machine 4
Current reference I _REF obtained from the regenerative state from torque current reference I _1q
By performing feedforward control of the voltage of the DC circuit on the basis of the above, it is possible to improve the responsiveness of the voltage control and reduce the fluctuation of the DC voltage.

FIG. 2 shows a second embodiment of the present invention. The same parts as those in FIG. 7 are denoted by the same reference numerals, and the description thereof will not be repeated.

In the second embodiment, as shown in FIG. 2, the output of the inverter 3 is obtained by multiplying 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 by the multiplier 12. The power P is obtained, and the output power P is added to the current reference _IREF output from the voltage control circuit 8 of the control system of the phase control rectifier.

Therefore, even in such a configuration, the voltage of the DC circuit is feed-forward controlled as described above, so that the response of the voltage control can be improved and the fluctuation of the DC voltage can be reduced.

FIG. 3 shows a third embodiment of the present invention. The same parts as those in FIG. 1 are denoted by the same reference numerals and their description is omitted, and only different points will be described here. In FIG. 3, the control system of the inverter 3A is omitted.

3 differs from FIG. 1 in that a plurality of inverters 3A, 3B and induction machines 4A, 4B driven by the respective inverters 3A, 3B are connected using a DC constant voltage circuit as a common power supply, and the speeds are independently controlled. The point is that control is performed.
For the DC common power system, the output power per each of inverters P _A, calculates the P _B, the output power P _A by the adder circuit 13, P _B
Is obtained, and this total P is added to the current reference I _REF output from the voltage control circuit 8 of the phase control rectifier control system. Since the sum P of the output powers P _A and P _B of each inverter is proportional to the sum of the currents input and output from the DC circuit, the same effect as described above can be obtained by adding this to the current reference I _REF. .

FIG. 4 shows a fourth embodiment of the present invention. The same parts as those in FIG. 3 are denoted by the same reference numerals, and the description thereof will be omitted. Only different points will be described. In FIG. 4, the control system on the inverter 3A side is omitted.

In FIG. 4, the difference from FIG. 3 is that when a plurality of inverters 3A and 3B have different output capacities, the rated output capacities KW _A and KW for each device to obtain output powers P _A and P _B for each inverter. _B
Is multiplied by the multiplier 14. As a result, the total output power P is proportional to the total current input to and output from the DC circuit even if the output capacity of the inverter 3 connected to the DC circuit is different. , The same operation and effect as described above can be obtained.

FIG. 5 shows a fifth embodiment of the present invention. The same parts as those in FIG. 2 are denoted by the same reference numerals, and the description thereof will be omitted. Only different points will be described here. In FIG. 5, the control system on the inverter 3A side is omitted.

In the fifth embodiment, an application of the embodiment of FIG. 2 to the DC common power system, a plurality of inverters 3A, 3B of the speed control circuit 6A, the induction unit 4A to the torque reference T _REF output from 6B,
4B rotational speed N _A, the resulting each inverter 3A multiplied by the multiplier 12 N _B, the output power P _A of 3B, the P _B, these output power P _A, P _B
Are added by an adder 13 and the sum P is added to the phase control rectifier 1
The same operation and effect as those of the above-described embodiment can be obtained by adding the current reference _IREF .

FIG. 6 shows a sixth embodiment of the present invention, in which the same parts as those in FIG. 5 are denoted by the same reference numerals, and the description thereof will be omitted. In FIG. 6, the control system of the inverter 3A is omitted.

6 differs from FIG. 5 in that inverters 3A, 3
When B has different output capacities, the output of the multiplier 12 is multiplied by the output capacities KW _A and KW _B of the respective inverters by the multiplier 14 to obtain output powers P _A and P _B for each device. As a result, the total power P becomes equal to the amount of power input / output to the DC common power supply,
The same operation and effect as described above can be obtained.

In each of the embodiments shown in FIGS. 3 to 6, the case where the number of inverters connected to the DC common power supply is two is described as an example. However, the present invention is not limited to two and may be three or more. This can be implemented in the same manner as described above.

Further, in each of the above-described embodiments, the torque reference T _REF or the torque current I _1q is used. However, the torque reference T _REF or the torque current I _Iq is obtained from the actually detected torque detection value or the primary current detection value of the induction machine 4. Of course, it may be possible.

[Effects of the Invention] As described above, according to the present invention, since the output power of the inverter is added to the voltage control circuit of the phase control rectifier control system, the current reference of the phase control rectifier is feedforward controlled. It is possible to provide a control device for an induction machine that does not generate overvoltage or undervoltage in the DC constant voltage circuit even when the induction machine is rapidly accelerated or decelerated.

[Brief description of the drawings]

FIGS. 1 to 6 are circuit diagrams showing first to sixth embodiments of a control device for an induction machine according to the present invention, and FIGS. 7 and 8 show control devices for different conventional induction machines, respectively. FIG. DESCRIPTION OF SYMBOLS 1 ... Phase control rectifier, 2 ... Smoothing filter, 3 ... Inverter 4, ... Induction machine, 5 ... Speed sensor, 6 ... Speed control circuit, 7 ... Inverter control circuit, 8 ... Voltage control circuit , 9 ... current control circuit, 10 ... phase control circuit, 11
... Dividers, 12,14 ... Multipliers, 13 ... Adders.

Claims (4)

(57) [Claims] 1. An induction machine control device which converts an alternating current into a direct current by a phase control rectifier capable of bidirectional power conversion, and converts the direct current output of the rectifier into an alternating current by an inverter to drive the induction machine. Calculating means for determining the output power of the inverter from the torque generated by the induction machine or the reference value of the generated torque and the number of revolutions; voltage control means for controlling a DC output voltage of the phase control rectifier; Current control means for controlling an output current or an input current; and addition means for adding an output power of the inverter and an output of the voltage control means to make a current reference of the phase control rectifier. Induction machine control device. 2. An induction machine control device in which an alternating current is converted into a direct current by a phase control rectifier capable of bidirectional power conversion, and a direct current output of the rectifier is converted into an alternating current by an inverter to drive the induction machine. Calculating means for separating a primary current of the induction machine into a torque component and an excitation component, and obtaining output power of the inverter based on a torque current component or a reference value of the torque current component and a terminal voltage of the induction machine; Voltage control means for controlling the DC output voltage of the 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. A control device for the induction machine, comprising: an adding means for setting a current reference of the phase control rectifier. 3. A method according to claim 1, wherein alternating current is converted into direct current by a phase control rectifier capable of bidirectional power conversion, and direct current output of the rectifier is converted into alternating current by a plurality of inverters to drive an induction machine corresponding to each inverter. In the control device for an induction machine, calculation means for respectively obtaining the output power of each inverter from the generated torque of each of the induction machines or a reference value of the generated torque and the number of revolutions, and a voltage for controlling a DC output voltage of the phase control rectifier. Control means, current control means for controlling the DC output current or input current of the phase control rectifier,
Control means for an induction machine, comprising: addition means for adding the sum of the output powers of the respective inverters obtained by the calculation means and the output of the DC control means to make the current reference of the phase control rectifier. apparatus. 4. A method according to claim 1, wherein alternating current is converted into direct current by a phase control rectifier capable of bidirectional power conversion, and direct current output of the 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, the primary current of each of the induction machines is separated into a torque component and an excitation component, and the output of each of the inverters is determined based on the torque current component or the reference value of the torque current component and the terminal voltage of the induction machine. Calculating means for obtaining power, voltage controlling means for controlling the DC output voltage of the phase-controlled rectifier, current controlling means for controlling the DC output current or input current of the phase-controlled rectifier, and each of the values determined by the calculating means. Adding means for adding the sum of the output power of the inverter and the output of the DC control means and using the sum as the current reference of the phase control rectifier. Electrical machine control unit.