KR20160053012A - Apparatus for motor drive control and method for energy storing in motor drive control - Google Patents

Abstract

An embodiment of the present invention relates to a motor driving apparatus and a method for storing energy of the motor driving apparatus. The motor driving apparatus comprises: a direct current-link (DC-link) for receiving energy to drive a motor from a power source; an inverter connected to the DC-link, and outputting alternating current voltage to the motor by converting the voltage of the DC-link from direct current to alternating current; and an energy storing unit connected to the DC-link, and storing energy. The energy storing unit charges the energy from the DC-link depending on the voltage in the DC-link or discharges energy to the DC-link, thereby increasing energy efficiency, and reducing a requirement capacity of a power facility.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an electric motor drive apparatus and an electric motor drive apparatus,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a motor drive apparatus and an energy storage method of a motor drive apparatus.

In general, an electric motor can consume a large amount of energy during an acceleration operation, and a large amount of energy may be generated during a regenerative operation.

In order to supply a large amount of energy to an electric motor for accelerating operation, the capacity of a power supply facility can be increased. However, since the required power during the normal driving operation of the motor is smaller than the power required during the acceleration operation, the capacity addition of the power supply facility for the acceleration operation of the motor may be a waste in terms of cost and energy efficiency.

A large amount of energy generated during regenerative operation of the motor can be dissipated as heat energy through the resistor. However, the thermal energy dissipated through the resistor is difficult to reuse and can be a waste of energy efficiency.

In order to improve the above-mentioned waste in terms of energy efficiency, one embodiment of the present invention provides a motor drive apparatus and a method for storing energy of the motor drive apparatus.

A motor driving apparatus according to an embodiment of the present invention includes: a DC-link (DC-link) that receives energy for operation of a motor from a power source; An inverter connected to the DC stage to convert the voltage of the DC stage from DC to AC and output an AC voltage to the motor; And an energy storage unit connected to the DC stage for storing energy; Wherein the energy storing unit charges energy from the DC terminal when the voltage of the DC terminal is higher than the first reference voltage and discharges energy to the DC terminal when the voltage of the DC terminal is lower than the second reference voltage, can do.

The energy storage unit may discharge energy when the inverter outputs an alternating voltage having a power higher than the rated power to the motor, and the energy storage unit may charge the energy when the motor performs a regeneration operation.

According to an aspect of the present invention, there is provided an energy storage method of a motor drive apparatus including: a power supply step of supplying energy from a power source to an electric motor; A discharging step of discharging energy stored in the battery when the electric power supplied to the electric motor is higher than the rated electric power; A stopping step of stopping the operation of the battery when the electric motor is driven and the electric power supplied to the electric motor is lower than the rated electric power; And a charging step of charging energy into the battery when the motor is in a regenerative operation mode. . ≪ / RTI >

Also, the discharging step discharges the stored energy even when the energy supply by the power source is interrupted, and the charging step may charge the energy even when the energy stored in the battery is lower than a predetermined energy.

The motor drive apparatus according to an embodiment of the present invention can increase the energy efficiency and reduce the required capacity of the power supply facility.

In addition, the motor driving apparatus can stably drive the motor even in the case of a power failure or a power supply failure, and can perform data storage in preparation for power failure and power supply abnormality.

1 is a view illustrating a motor driving apparatus according to an embodiment of the present invention.
2 is a diagram illustrating an energy flow of a motor driving apparatus according to an embodiment of the present invention.
3 is a circuit diagram showing the energy storage unit 130 included in FIG.
4 is a graph illustrating speed, torque, power, and energy flow according to driving time of a motor driving apparatus according to an embodiment of the present invention.
5 is a flowchart illustrating an energy storing method of a motor driving apparatus according to an embodiment of the present invention.

It is noted that the technical terms used herein are used only to describe specific embodiments and are not intended to limit the invention. It is also to be understood that the technical terms used herein are to be interpreted in a sense generally understood by a person skilled in the art to which the present invention belongs, Should not be construed to mean, or be interpreted in an excessively reduced sense. Further, when a technical term used herein is an erroneous technical term that does not accurately express the spirit of the present invention, it should be understood that technical terms that can be understood by a person skilled in the art are replaced. In addition, the general terms used in the present invention should be interpreted according to a predefined or prior context, and should not be construed as being excessively reduced.

Also, the singular forms "as used herein include plural referents unless the context clearly dictates otherwise. In this application, the term "comprising" should not be construed as necessarily including the various elements or steps described in the specification, and some of the elements or portions thereof may not be included, Or < / RTI > additional elements or steps.

Further, the suffix "part" for a component used in the present specification is given or mixed in consideration of ease of specification, and does not have a meaning or role that is different from itself.

Furthermore, terms including ordinals such as first, second, etc. used in this specification can be used to describe various elements, but the elements should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein like reference numerals refer to like or similar elements throughout the several views, and redundant description thereof will be omitted.

In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. It is to be noted that the accompanying drawings are only for the purpose of facilitating understanding of the present invention, and should not be construed as limiting the scope of the present invention with reference to the accompanying drawings.

1 is a view illustrating a motor driving apparatus according to an embodiment of the present invention.

Referring to FIG. 1, an electric motor driving apparatus 100 may supply energy to a motor 300 by supplying energy from a power source 200, thereby driving the motor 300.

Referring to FIG. 1, the motor drive apparatus 100 may include a DC stage 110, an inverter 120, an energy storage unit 130, and a rectification unit 140.

The DC stage 110 can receive energy for operation of the electric motor 300 from the power source 200. For example, the DC-link may comprise a capacitor. The capacitor can smooth the voltage converted to the direct current voltage by the rectifying part 140. The DC stage 110 may serve as a relay point of energy flow to the power source 200, the motor 300, and the energy storage unit 130. Details of the energy flow will be described later with reference to Fig.

The inverter 120 is connected to the DC terminal 110 to convert the voltage of the DC terminal 110 from DC to AC and output the AC voltage to the motor 300. For example, the inverter 120 converts a DC voltage into a plurality of phase AC voltages according to a drive control signal, and applies them to coils (corresponding to the plurality of phases) of the motor 300 to generate a magnetic field . Specifically, the stator of the motor 300 is a permanent magnet having a polarity. Specifically, three coils (three phases) are distributed in a stator of the motor 300, and the inverter 120 is disposed in a stator To generate a rotating magnetic field. A magnetic field may be induced in the rotor of the electric motor 300 according to the rotating magnetic field. Therefore, the rotor rotates about the stator due to the interaction of the generated magnetic field.

The inverter 120 may include a plurality of switches. The plurality of switches include a plurality of upper switch elements connected to the + power terminal, and each of the upper switch elements and the plurality of lower switch elements provided between the power terminals, and each of the upper switch elements and the lower switch elements The contacts may be connected to the respective coils of the motor (300).

Further, the plurality of switches can switch the DC voltage to the plurality of phase AC voltages by switching according to the drive control signal. For example, the plurality of switches may include a transistor and a diode, and the transistor may include an IGBT or a FET in consideration of power capacity, switching time, and the like. Here, switching can be performed by inputting the drive control signal to the gate terminal of the transistor.

The energy storage unit 130 may be connected to the DC terminal 110 to store energy. The energy storing unit 130 charges energy from the DC terminal 110 when the voltage of the DC terminal 110 is higher than the first reference voltage and the voltage of the DC terminal 110 is higher than the second reference voltage Energy can be discharged to the DC terminal 110 when the voltage is low. Here, the first reference voltage may be greater than or equal to the second reference voltage. For example, the first reference voltage may be slightly higher than the DC short-circuit voltage or equal to the DC short-circuit voltage during the normal driving operation of the motor. The second reference voltage may be slightly lower than the DC short-circuit voltage during the normal driving operation of the motor, or may be equal to the DC short-circuit voltage.

For example, when the inverter 120 outputs an AC voltage having a power higher than the rated power to the motor 300, the DC terminal 110 is less than the power received from the power supply 200 to the inverter 120 Can be. Accordingly, the DC voltage may be lowered, and the DC voltage may be lower than the second reference voltage. At this time, the energy storage unit 130 may discharge energy to the DC terminal 110.

For example, when the electric motor 300 performs a regenerative operation, the DC terminal 110 can receive energy from the electric motor 300. Accordingly, the DC short-circuit voltage can be raised, and the DC short-circuit voltage can be higher than the first reference voltage. At this time, the energy storage unit 130 may charge energy from the DC terminal 110. [

Also, the energy storage unit 130 may receive energy from the power source 200 when the stored energy is lower than a predetermined energy. Generally, since the energy efficiency of the motor drive apparatus 100 is not 100%, the energy stored in the energy storage unit 130 can be reduced as time passes. Accordingly, the energy storage unit 130 receives energy from the power source 200, so that the motor drive apparatus 100 can drive the motor 300 stably. For example, when the electric motor 300 is temporarily stopped, the energy storage unit 130 can receive energy directly from the power source 200.

Also, when the energy supply by the power source 200 is stopped, the energy storage unit 130 may discharge stored energy. Here, the interruption of the energy supply by the power source 200 means a power failure and a power source abnormality. That is, the energy stored in the energy storing unit 130 is discharged in the case of power failure and power supply failure, so that the motor driving apparatus 100 can stably drive the motor 300 and save data for power failure and power supply abnormality It can be done by hand.

The rectifying unit 140 can convert an AC voltage supplied from the power source 200 into a DC voltage. For example, the rectifying unit 140 may include a plurality of diodes to convert an AC voltage to a DC voltage.

Meanwhile, when the power source 200 supplies the DC voltage, the rectifying unit 140 may not be included in the motor driving apparatus 100.

2 is a diagram illustrating an energy flow of a motor driving apparatus according to an embodiment of the present invention.

First, the energy supplied from the power source 200 may flow through the rectifying unit 140 to the DC stage 110. The energy may be supplied to the motor 300 or to the energy storage unit 130.

Second, the energy supplied to the electric motor 300 can flow from the DC terminal 110 through the inverter 120. [ The energy generated by the regenerative operation of the electric motor 300 may flow through the inverter 120 to the DC stage 110. [ For example, the electric motor 300 can repeat the driving operation and the regenerative operation for the operation of the hoisting load (elevator, crane) and the inertial load which are the four-upper limit load. Accordingly, the electric motor 300 can repeatedly generate a large amount of energy and generate energy.

Third, the energy stored in the energy storage unit 130 may be discharged to the DC terminal 110 or charged from the DC terminal 110. The discharged energy can be used for the accelerating operation or the uninterrupted operation of the electric motor 300. The energy to be charged may be the energy that is generated through the regenerative operation of the electric motor 300 or the energy that is charged through the power source 200 to charge the insufficient energy.

3 is a circuit diagram showing the energy storage unit 130 included in FIG.

Referring to FIG. 3, the energy storage unit 130 included in the motor drive apparatus 100 may include a battery 131 and a converter 132.

The battery 131 may store energy for charging and discharging.

The converter 132 is connected between the battery 131 and the DC terminal 110 so as to step up or down the voltage. Here, the converter 132 may include a first switch 133, a second switch 134, a capacitor 135, and an inductor 136 as a bidirectional synchronous buck / boost converter.

The converter 132 can turn on or off the first switch 133 and the second switch 134 to boost or lower the voltage of the energized conduction.

Specifically, the intermediate voltage between the first switch 133 and the second switch 134 will be described. When the first switch 133 is turned on and the second switch 134 is turned off, the magnitude of the intermediate voltage is equal to the magnitude of the input voltage. Further, in the second state in which the first switch 133 is turned off and the second switch 134 is turned on, the magnitude of the intermediate voltage is zero. The on / off control of the first switch 133 and the second switch 134 may mean repetition of the first state and the second state.

By repeating the first state and the second state, the intermediate voltage can be in the form of a square wave. At this time, the capacitor 135 and the inductor 136 can filter high-frequency components contained in the intermediate voltage. Thus, the intermediate voltage may be converted into the form of a smoothed voltage while passing through the converter 132.

Here, the magnitude of the smoothed voltage is an average voltage of the square wave. Thus, the magnitude of the smoothed voltage is a product of the voltage of the first state of the square wave and the duty ratio of the square wave. If the duty ratio is not 100%, the magnitude of the smoothed voltage is smaller than the voltage of the first state of the square wave.

4 is a graph illustrating speed, torque, power, and energy flow according to driving time of a motor driving apparatus according to an embodiment of the present invention.

Referring to FIG. 4, (a) represents the speed of the electric motor with respect to time. (b) The graph shows the torque of the electric motor with respect to time. (c) The graph shows the electric power of the motor over time. (d) The graph shows the energy flow over time.

At intervals of 0 second to 2 seconds, the motor is accelerated. The torque is maintained at a value of 150% of the rated torque, and as the speed is increased, the electric power supplied to the motor can be increased. For example, when the electric power supplied to the electric motor is greater than the electric power of 67.5 kW, which is the electric power at the constant speed operation, the energy stored in the energy storage unit 130 can be supplied to the electric motor.

At intervals of 2 to 7 seconds, the motor is operated at a constant speed. The torque is maintained at a value of 90% of the rated torque, and the speed and power can be stabilized.

At intervals of 7 to 9 seconds, the motor is regeneratively operated. The torque is maintained at a value of -30% of the rated torque, and the electric power of 22.5 kW generated in the electric motor can be stored in the energy storage unit 130.

At intervals of 9 to 14 seconds, the motor stops. The electric power is not supplied to the electric motor, and the energy supplied from the electric power source can be charged to the energy storage unit 130.

At intervals of 14 to 23 seconds, the electric motor can be operated under pulley. At this time, the energy generated by the motor may be greater than during hoisting operation. Accordingly, the energy storage unit 130 can charge a large amount of energy.

In the whole section, the average power consumption is 24.8 kW. By supplying an average power consumption of 6.09 kW at the time of acceleration in the energy storage unit 130, energy consumption of about 25% can be saved.

Hereinafter, an energy storing method of a motor driving apparatus according to an embodiment of the present invention will be described. Since the energy storage method of the motor drive apparatus can be performed in the motor drive apparatus 100 described above with reference to FIG. 1, the same or corresponding contents to those described above will not be described redundantly.

5 is a flowchart illustrating an energy storing method of a motor driving apparatus according to an embodiment of the present invention.

Referring to FIG. 5, an energy storage method of a motor driving apparatus according to an embodiment of the present invention may include a power supply step S10, a discharge step S20, a stop step S30, and a charge step S40 have.

The electric motor driving apparatus in the power supply step S10 can supply energy from the electric power source and supply the energy to the electric motor.

The electric motor driving apparatus in the discharging step S20 can discharge the energy stored in the battery when the electric power supplied to the electric motor is higher than the rated electric power. Also, the motor driving apparatus in the discharging step (S20) can discharge the stored energy even when the energy supply by the power source is interrupted.

The motor driving apparatus in the stopping step S30 can stop the operation of the battery when the electric motor is in the driving operation and the electric power supplied to the electric motor is lower than the rated electric power. For example, when the motor operates at a constant speed, the energy supplied from the power source can be supplied to the motor as it is.

The motor driving apparatus in the charging step (S40) can charge the battery with energy when the motor is in the regenerative operation. In addition, the motor driving apparatus in the charging step S40 can charge the energy even when the energy stored in the battery is lower than a certain energy.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Therefore, the spirit of the present invention should not be construed as being limited to the above-described embodiments, and all of the equivalents or equivalents of the claims, as well as the following claims, I will say.

100: motor drive unit 110:
120: inverter 130: energy storage unit
131: Battery 132: Converter
140: rectification part 200: power source
300: electric motor
S10: Power supply step S20: Discharge step
S30: Stop step S40: Charging step

Claims (6)

A DC-link (DC-link) receiving energy from the power source for operating the motor;
An inverter connected to the DC stage to convert the voltage of the DC stage from DC to AC and output an AC voltage to the motor; And
An energy storage unit connected to the DC stage to store energy; Lt; / RTI >
Wherein the energy storage unit charges energy from the DC terminal when the voltage of the DC terminal is higher than the first reference voltage and discharges energy to the DC terminal when the voltage of the DC terminal is lower than the second reference voltage, .
The method according to claim 1,
Wherein when the inverter outputs an AC voltage having a power higher than the rated power to the motor, the energy storage unit discharges energy,
And the energy storage unit charges energy when the motor is in the regenerative operation.
The method according to claim 1,
Wherein the energy storage unit receives energy from the power source when the stored energy is lower than a predetermined energy,
And the energy storage unit discharges the stored energy when the energy supply by the power supply is interrupted.
The plasma display apparatus according to claim 1,
A battery for storing energy for charging and discharging; And
A converter connected between the battery and the DC terminal for boosting or reducing the voltage; And an electric motor drive device.
A power supply step of supplying energy from a power source and supplying energy to the motor;
A discharging step of discharging energy stored in the battery when the electric power supplied to the electric motor is higher than the rated electric power;
A stopping step of stopping the operation of the battery when the electric motor is driven and the electric power supplied to the electric motor is lower than the rated electric power; And
A charging step of charging energy into the battery when the motor is in a regenerative operation; Wherein the energy storage method comprises:
6. The method of claim 5,
Wherein the discharging step discharges stored energy even when the supply of energy by the power source is interrupted,
Wherein the charging step charges the energy even when the energy stored in the battery is lower than a predetermined energy.

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