KR20140050974A - Apparatus and method for driving motor - Google Patents

Abstract

The present invention relates to a motor driving device and a driving method thereof, capable of reducing noise generated in switching by configuring inverters within a power conversion device in parallel, minimizing heat generation due to the switching, and increasing energy conversion efficiency of the driving device by reducing a pulsating size of a motor phase current and improving motor efficiency. The motor driving device comprises a motor including multiple double coils including first and second sub-coils individually and multiple terminals connected to the first and second sub-coils individually; and the power conversion device including first and second inverters and supplying driving voltages output from the first and second inverters to the first and second sub-coils, respectively.

Description

[0001] Apparatus and method for driving motor [0002]

More particularly, the present invention relates to an electric motor driving apparatus and a driving method thereof. More particularly, the present invention relates to a motor driving apparatus and a driving method thereof, And more particularly, to a motor driving apparatus and a driving method capable of increasing the energy conversion efficiency of a driving apparatus by improving the efficiency of the motor by reducing the pulsation size of the motor.

An electric vehicle refers to a vehicle that is driven by the electrical power of a battery, which is a secondary battery, instead of the mechanical power of an engine using fossil fuel.

In this case, the induction motor for generating electric power in the electric vehicle is arranged in a distributed manner with a winding, and a three-phase power source having a phase difference of 120 degrees is used to make a rotating system.

In order to control these motors, frequency and voltage are controlled to control torque or speed. At this time, inverter is used, and the three-phase output of the inverter is connected to the three-phase terminal of the motor.

Referring to FIG. 1, a motor driving apparatus for a small capacity electric vehicle according to the related art includes an electric motor 10 having three internal windings and three terminals U, V and W respectively connected to the windings The PWM controller 21 includes a power inverter 20 having an inverter 22 controlled by the PWM controller 21 and is controlled by the PWM controller 21 to output a three phase The power source is supplied to the three terminals (U, V, W) of the electric motor 10 to generate torque in the electric motor 10, and the vehicle is driven by the generated torque.

2, an electric motor driving apparatus for a large capacity electric vehicle according to the related art has three double windings internally to receive a large current, and three terminals U ' And a power converter 40 including an inverter 42 controlled by a PWM controller 41. The inverter 30 is controlled by the PWM controller 41 to control the inverter 30, Phase power source having a phase difference of 120 degrees outputted from the motor 42 to the three terminals U ', V', W 'of the electric motor 30 to generate torque in the electric motor 30, Drive the vehicle with torque.

At this time, in order to flow a large current, a power device is further connected to the power device of the inverter 42 in parallel to provide a current on the motor 1.

Accordingly, the conventional small capacity electric vehicle and / or the electric motor drive apparatus of the large capacity electric vehicle have one inverter controlled by one PWM controller to drive the electric motor by controlling the power source and the frequency inputted to the electric motor.

At this time, PWM switching, which is used as a method for controlling voltage and frequency, inevitably generates noise. To reduce this noise, PWM switching frequency is used above the audible frequency.

This causes a problem that a large amount of heat is generated in a power device of an inverter which is switched at a high speed.

In addition, for power devices switching currents of hundreds of amperes, greater switching losses occur compared to relatively small power devices switching dozens of amperes.

Although an electric vehicle has been described as an example of driving by driving of the electric motor, the problem is not limited to an electric vehicle, but may occur in other fields driven by driving of the electric motor.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the conventional art as described above, and it is an object of the present invention to provide a power conversion apparatus and a power conversion apparatus which can reduce noise generated during switching, And to improve the efficiency of the motor to increase the energy conversion efficiency of the drive device.

According to an aspect of the present invention, there is provided an electric vehicle including: an electric motor including a plurality of double windings each including first and second sub windings and a plurality of terminals connected to the first and second sub windings; And a power conversion device that includes first and second inverters connected in parallel to each other and supplies a drive voltage output from the first and second inverters to the first and second sub windings, Lt; / RTI >

At this time, the first and second sub-windings of the plurality of double windings may be connected to one neutral point.

In addition, the first sub-winding of the plurality of double windings may be connected to a first neutral point, and the second sub-winding of the plurality of double windings may be connected to a second neutral point.

Meanwhile, the electric motor includes a plurality of terminals respectively connected to the first and second sub-windings, and the first and second inverters are respectively connected to the first and second sub-windings through the plurality of terminals , And simultaneously supplies the driving voltage.

The power conversion apparatus according to the present invention includes: a first PWM controller for outputting a first switching signal to the first inverter to control operation; A second PWM controller for outputting a second switching signal to the second inverter to control operation thereof; And a PWM controller coupled to the first PWM controller and the second PWM controller to synchronize the first and second switching signals while delaying the first switching signal or the second switching signal by 180 degrees do.

The present invention also provides a method of driving an electric motor including a plurality of double windings each including first and second sub windings, the method comprising the steps of: The present invention also provides a method of driving an electric motor by simultaneously supplying a drive voltage output from a first inverter and a second inverter to the first and second sub-windings.

In this case, the PWM controller connected to the first and second PWM controllers for controlling the first and second inverters outputs the first and second switching signals, respectively, to synchronize the first and second switching signals, 1 switching signal or the second switching signal by 180 degrees.

Therefore, the first and second switching signals have a phase difference of 180 degrees from each other and have the same frequency.

According to the present invention, since the inverters in the power converter are arranged in parallel, the current applied to the motor has a frequency twice that of the switching signal even if a switching signal having a frequency lower than that of the conventional one is used. And can be induced outside the audible frequency domain to reduce noise.

Further, by reducing the pulsation of the current applied to the motor, the harmonic amplitude can be reduced, and the loss due to the harmonic current, which can not contribute to the torque of the motor, can be reduced.

Therefore, not only the switching loss of the power semiconductor device of the inverter due to the low switching frequency can be reduced, but also the harmonic amplitude of the input current of the motor can be reduced to improve the efficiency of the motor.

1 is a diagram showing an example of a conventional motor drive apparatus for a small capacity electric vehicle.
2 is a diagram showing an example of a motor driving apparatus of a conventional large-capacity electric vehicle.
3 is a schematic view showing a motor driving apparatus according to an embodiment of the present invention.
4 is a detailed view showing a motor driving apparatus according to an embodiment of the present invention.
5 is a detailed view showing a motor driving apparatus according to another embodiment of the present invention.
6 is a diagram showing a waveform of a current applied to a winding according to a switching signal in the prior art.
7 is a graph showing a waveform of a current applied to a winding according to a switching signal in the embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The electric motor driving apparatus and the driving method according to the present invention described below can be applied in many fields such as an electric vehicle operated by driving a motor for the purpose of obtaining the same effect obtained by the present invention.

FIG. 3 is a schematic view showing a motor driving apparatus according to an embodiment of the present invention, FIG. 4 is a detailed view showing a motor driving apparatus according to an embodiment of the present invention, and FIG. FIG. 6 is a view showing a waveform of a current applied to a winding according to a switching signal in the prior art, and FIG. 7 is a graph showing the waveform of a current applied to a winding according to a switching signal Fig. 8 is a graph showing the waveform of the current.

3 and 4, an electric motor driving apparatus according to the present invention includes an electric motor 100 and a motor 100 connected to the electric motor 100. The electric motor 100 receives power supplied from the outside, And a power conversion device (200).

In detail, the electric motor 100 has three double windings internally powered by three phases of power, and includes a plurality of terminals each connected to the three double windings.

That is, the motor 100 has first, second, and third double windings 110, 120, and 130 internally supplied with power from one of three power sources, and each of the double windings 110 and 120 130 and the first sub-windings 110a, 120a, 130a and the second sub-windings 110b, 130a, 130b are comprised of first and second sub-windings 110a, 110b, 120a, 120b, 120b, and 130b are supplied power independently of each other.

Thus, the three double windings each comprise two sub-windings.

The electric motor 100 also includes terminals U1, U2, V1, V2, W1 and W2 connected to the first and second sub-windings 110a, 110b, 120a, 120b, 130a and 130b, Connected to the first sub-windings (110a, 120a, 130a) and first terminals (U1, V1, W1) connected to the second sub-windings (110b, 120b, 130b) 2 terminals U2, V2, and W2.

At this time, as in this embodiment, the first and second sub-windings 110a, 110b, 120a, 120b, 130a, and 130b may be connected to one neutral point S.

However, as shown at 5, the first sub-windings 110a, 120a and 130a are connected to the first neutral point S1 and the second sub-windings 110b, 120b and 130b are connected to the second neutral point S1, (S2), such that the first and second sub-windings are connected to different midpoints.

The power inverter 200 includes a first inverter 210 and a second inverter 220 connected in parallel to each other to receive power supplied from an external source and supply driving power to the motor 100, A first PWM controller 230 for controlling the first inverter 210, a second PWM controller 240 for controlling the second inverter 220 and a second PWM controller 240 for controlling the first PWM controller 230 and the second PWM And a PWM controller 250 for controlling the controller 240.

In this case, a power supply (external power supply) supplied from the outside is a power supply supplied from a power supply unit 300 and supplied via a power disconnect unit (PDU) 400, (200) and the power conversion apparatus (200) to intermittently supply power between the power supply unit (300) and the power conversion apparatus (200) Thereby protecting the apparatus 200 and the power supply unit 200.

The external power source is not limited to the above structure and may be provided between the power conversion apparatus 200 and the power cutoff unit 400 or between the power cutoff unit 400 and the power supply unit 300, And a structure in which a further installation is provided in between.

The first inverter 210 includes a plurality of power semiconductor devices 211 and performs switching operation under the control of the first PWM controller 230 to supply external power to the motor 100).

The second inverter 220 includes a plurality of power semiconductor devices 221 and performs switching operation under the control of the second PWM controller 240 to supply external power to the motor 100 .

The first and second inverters 210 and 220 convert the supplied DC power to AC power and supply the AC power to the motor 100 .

The first inverter 210 is connected to the first terminals U1, V1 and W1 and is connected to the first sub-windings 110a, 120a and 130a. The second inverter 220, Are connected to the second terminals U2, V2 and W2 and are connected to the second sub-windings 110b, 120b and 130b.

Accordingly, the first inverter 210 applies driving power to the first sub-windings 110a, 120a, and 130a, and the second inverter 220 applies driving power to the second sub-windings 110b, 120b, and 130b ), The first and second sub-windings are supplied with driving power through different inverters, respectively.

That is, the first and second sub-windings operate independently and receive the driving power from the first and second inverters 220 at the same time.

At this time, since the connection between the inverter and the sub-windings is a commonly used technique, detailed description is omitted.

The first PWM controller 230 is connected to the first inverter 210 to generate and output a first switching signal to control the operation of the first inverter 210. The first PWM controller 230 generates a first PWM signal, The voltage and the frequency of the external power supplied to the first inverter 210 are varied and output to be supplied to the motor 100 under the control of the controller 100. [

Similarly, the second PWM controller 240 is connected to the second inverter 220 to generate and output a second switching signal to control operation of the second inverter 220, and the second PWM controller 240 The voltage and the frequency of the external power supplied to the second inverter 220 are varied and output to be supplied to the motor 100 under the control of the controller 240. [

The PWM controller 250 is connected to the first and second PWM controllers 230 and 240 and generates a first switching signal generated from the first PWM controller 230 and a second switching signal generated from the second PWM controller 240 The first switching signal or the second switching signal is delayed by 180 degrees. Accordingly, the first and second switching signals have a phase difference of 180 degrees and have the same frequency.

According to the present invention, the motor 100 is driven by the first inverter 210 controlled by the first PWM controller 230 and output to the first sub-windings U1, V1, and W1 through the first terminals U1, The second PWM controller 240 controls the driving power supplied to the first and second inverters 110a, 120a and 130a and the second inverter 220 through the second terminals U2, V2 and W2, And is operated by receiving driving power supplied to the windings 110b, 120b, and 130b.

Meanwhile, in the present invention, the frequencies of the first and second switching signals output from the first and second PWM controllers 230 and 240 for controlling the first and second inverters 210 and 220, respectively, Use a low-frequency signal that is much lower or about half the frequency you are using.

At this time, the frequency of the second switching signal output from the second PWM controller 240 should be the same as the frequency of the first switching signal output from the second PWM controller 230.

Accordingly, in the present invention, the PWM controller 250 is provided to output the first and second switching signals having the same frequency and 180 degree phase difference.

The effect of the driving apparatus that operates according to the configuration of the present invention will be described with reference to FIGS. 6 and 7. FIG. In this case, the current is applied through the U terminal among the terminals of the motor, and the same applies to the case where the current is applied through the other terminal.

Referring to FIG. 7 showing a waveform of a current applied to a winding according to an embodiment of the present invention, the first switching signal S1 and the second switching signal S2 have a phase difference of 180 degrees The first and second inverters 210 and 220 output the driving currents Iu1 and Iu2 to the terminals U1 and U2 of the motor 100 in response to the first and second inverters 210 and 220, So that the electric current of Iu1 + Iu2 is supplied to the electric motor 100. [

Therefore, even if a switching signal having a frequency lower than that of the conventional one is used, the 1-phase current applied to the motor 100 has twice the frequency of the switching signal, so that noise caused by switching can be reduced, Noise can be reduced.

6 and 7, the current Iu applied to the motor according to the embodiment of the present invention is smaller than the current Iu applied to the motor according to the conventional art Iu1 + Iu2) shows a very small pulsation.

Further, by reducing the pulsation of the current applied to the motor, the harmonic amplitude can be reduced, and the loss due to the harmonic current, which can not contribute to the torque of the motor, can be reduced.

Therefore, not only the switching loss of the power semiconductor device of the inverter due to the low switching frequency can be reduced, but also the harmonic amplitude of the input current of the motor can be reduced to improve the efficiency of the motor.

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, Various modifications, alterations, and changes may be made without departing from the scope of the present invention.

Therefore, the embodiments described in the present invention and the accompanying drawings are intended to illustrate rather than limit the technical spirit of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments and accompanying drawings . The scope of protection of the present invention should be construed according to the claims, and all technical ideas within the scope of equivalents should be interpreted as being included in the scope of the present invention.

100: electric motor 110, 120, 130: double winding
200: power converter 210: first inverter
220: second inverter 230: first PWM controller
240: second PWM controller 250: PWM control unit
300: Power supply unit 400: Power interruption unit (PDU)

Claims (8)

An electric motor including a plurality of double windings each including first and second sub windings and a plurality of terminals respectively connected to the first and second sub windings; And
And a power conversion device including first and second inverters connected in parallel to each other and supplying a drive voltage output from the first and second inverters to the first and second sub-windings, respectively. The method according to claim 1,
Wherein the first and second sub-windings of the plurality of double windings are connected to one neutral point. The method according to claim 1,
Wherein a first sub-winding of the plurality of double windings is connected to a first neutral point and a second sub-winding of the plurality of double windings is connected to a second neutral point. The method according to claim 1,
Wherein the motor includes a plurality of terminals respectively connected to the first and second sub-windings,
Wherein the first and second inverters are connected to the first and second sub-windings through the plurality of terminals, respectively, and supply the drive voltage at the same time. The method according to claim 1,
A first PWM controller for outputting a first switching signal to the first inverter to control operation of the first inverter;
A second PWM controller for outputting a second switching signal to the second inverter to control operation thereof; And
And a PWM controller coupled to the first PWM controller and the second PWM controller to synchronize the first and second switching signals while delaying the first switching signal or the second switching signal by 180 degrees Motor drive device. A method of driving an electric motor including a plurality of double windings each including first and second sub windings,
A first sub-winding connected to the first sub-winding and a second sub-winding connected to the first and second sub-windings, the first and second sub-windings being connected to the first and second sub- Driving method. The method according to claim 6,
A PWM controller connected to the first and second PWM controllers for controlling the first and second inverters outputs the first and second switching signals, respectively, for synchronizing the first and second switching signals, Signal or the second switching signal is delayed by 180 degrees. 8. The method of claim 7,
Wherein the first and second switching signals have a phase difference of 180 degrees from each other and have the same frequency.

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