Patent Application
20140320051
1. Field of the Invention
The present invention relates to motor driving technology and more particularly, to a motor winding and power electronic switch assembly having switchable output capability.
2. Description of the Related Art
A conventional motor winding assembly is known, as shown in
However, according to the design of the aforesaid Y-connected motor winding assembly, if you wish to obtain a relatively higher no-load speed during operation of the motor, the starting torque of the motor will be lowered, on the contrary, enabling the motor to provide a relatively higher starting torque, the no-load speed of the motor will be constrained, thus, the motor operational speed range is limited.
Taiwan Patent Publication No. 401923 discloses a technique for switching motor windings between series and parallel configurations. Thus, the motor windings can be switched to the series configuration for low-speed and high-torque application to provide a high torque output. Further, if you wish to increase the speed range after the revolving speed of the motor has been increased, you can switch the motor windings to the parallel configuration to increase the speed range.
Further, Taiwan Patent Publication No. 200538322 discloses another technique for changing the motor driving configuration by using a switching control means to control every switch, determining the number of turns of winding to be connected to the motor.
The present invention has been accomplished under the circumstances in view. It is the main object of the present a motor winding and power electronic switch assembly having switchable output capability, which changes the motor driving configuration to increase the working speed range by means of controlling on/off status of every switch.
To achieve this and other objects of the present invention, a motor winding and power electronic switch assembly having switchable output capability comprises a first winding set comprising a first upper winding and a first lower winding, the first upper winding and the first lower winding each having one end thereof connected to a common contact, a first switch set comprising four power electronic switches electrically connected to the first winding set, a second winding set comprising a second upper winding and a second lower winding, the second upper winding and the second lower winding each having one end thereof connected to the common contact, a second switch set comprising four power electronic switches electrically connected to the second winding set, a third winding set comprising a third upper winding and a third lower winding, the third upper winding and the third lower winding each having one end thereof connected to the common contact, a third switch set comprising four power electronic switches electrically connected to the third winding set, and a configuration control means adapted for controlling on/off of the power electronic switches to selectively combine the first winding set, the second winding set and the third winding set into a H type configuration or Y type configuration, achieving the effect of switching output status. The first switch set, the second switch set and the third switch set are electrically connected to a power source and a ground terminal.
Other advantages and features of the present invention will be fully understood by reference to the following specification in conjunction with the accompanying drawings, in which like, reference signs denote like components of structure.
Referring to
The first winding set AW comprises a first upper winding AW1 and a first lower winding AW2. The first upper winding AW1 and the first lower winding AW2 each have one end thereof connected to a common contact P. Further, the first upper winding AW1 and the first lower winding AW2 are symmetrical. In this embodiment, the symmetrical characteristic means that the upper winding and the lower winding have the same number of turns. However, it is still allowable that the windings are configured to have a number of turns approximately similar, i.e., the aforesaid symmetric characteristic is not limited to the condition of having the same number of turns.
The first switch set 11 comprises four power electronic switches electrically connected to the first winding set AW. The four power electronic switches of the first switch set 11 are designated as the first power electronic switch S1, the second power electronic switch S2, the third power electronic switch S3, and the fourth power electronic switch S4. The first power electronic switch S1 and the second power electronic switch S2 are connected in series, and both connected to the first upper winding AW1 to exhibit a Y-connected circuit. The third power electronic switch S3 and the fourth power electronic switch 54 are connected in series, and both connected to the first lower winding AW2 to exhibit a Y-connected circuit.
The second winding set BW comprises a second upper winding BW1 and a second lower winding BW2. The second upper winding BW1 and the second lower winding BW2 each have one end thereof connected to the aforesaid common contact P. Further, the second upper winding BW1 and the second lower winding BW2 are symmetrical. In this embodiment, the symmetrical characteristic means that the upper winding and the lower winding have the same number of turns.
The second switch set 21 comprises four power electronic switches electrically connected to the second winding set BW. The four power electronic switches of the second switch set 21 are designated as the fifth power electronic switch S5, the sixth power electronic switch S6, the seventh power electronic switch S7, and the eighth power electronic switch S8. The fifth power electronic switch S5 and the sixth power electronic switch S6 are connected in series, and both connected to the second upper winding BW1 to exhibit a Y-connected circuit. The seventh power electronic switch S7 and the eighth power electronic switch S8 are connected in series, and both connected to the second lower winding BW2 to exhibit a Y-connected circuit.
The third winding set CW comprises a third upper winding CW1 and a third lower winding CW2. The third upper winding CW1 and the third lower winding CW2 each have one end thereof connected to the aforesaid common contact P. Further, the third upper winding CW1 and the third lower winding CW2 are symmetrical. This symmetrical characteristic, as stated above, is not limited to the condition of having the same number of turns.
The third switch set 31 comprises four power electronic switches electrically connected to the third winding set CW. The four power electronic switches of the second switch set 31 are designated as the ninth power electronic switch S9, the tenth power electronic switch S10, the eleventh power electronic switch S11, and the twelfth power electronic switch S12. The ninth power electronic switch 59 and the tenth power electronic switch S10 are connected in series, and both connected to the third upper winding CW1 to exhibit a Y-connected circuit, The eleventh power electronic switch S11 and the twelfth power electronic switch S12 are connected in series, and both connected to the third lower winding CW2 to exhibit a Y-connected circuit.
The mode control means is adapted for controlling on/off of the power electronic switches to combine the first winding set AW, the second winding set BW and the third winding set CW into an H type mode or Y type mode and to further achieve the desired output status switching effects. This embodiments to cause a synchronized action or complementary action on each power electronic switch S1˜S12 of the first switch set 11, second switch set 21 and third switch set 31. The synchronized action means that the switches of each selected matching pair are synchronously turned on or synchronously turned off. The complementary action means that one switch of each selected matching pair is OFF and the other switch is ON. Further, when each power electronic switch S1˜S12 is ON, a pulse width modulation (PWM) signal is applied to control each power electronic switch S1˜S12, combining the first winding set AW, the second winding set BW and the third winding set CW to form a H type mode or Y type mode.
The first switch set 11, the second switch set 21 and the third switch set 31 are electrically connected to a power source VCC and a ground terminal GND.
If you wish to combine the first winding set AW, the second winding set 11W and the third winding set CW into an H type mode, the operation is outlined hereinafter.
The status of the synchronous action in the mode control means is: the first power electronic switch S1 and the fourth power electronic switch S4 work synchronously; the second power electronic switch S2 and the third power electronic switch S3 work synchronously; the fifth power electronic switch S5 and the eighth power electronic switch S8 work synchronously; the sixth power electronic switch S6 and the seventh power electronic switch S7 work synchronously; the ninth power electronic switch S9 and the twelfth power electronic switch S12 work synchronously; the tenth power electronic switch S10 and the eleventh power electronic switch S11 work synchronously.
The status of the complementary action in the mode control means is; the first power electronic switch S1 and the second power electronic switch S2 work in a complementary manner; the third power electronic switch 53 and the fourth power electronic switch S4 work in a complementary manner; the fifth power electronic switch S5 and the sixth power electronic switch S6 work in a complementary manner; the seventh power electronic switch 57 and the eighth power electronic switch S8 work in a complementary manner; the ninth power electronic switch 59 and the tenth power electronic switch S10 work in a complementary manner; the eleventh power electronic switch S11 the twelfth power electronic switch S12 work in a complementary manner.
Further, the mode control means comprises: terminal voltages or voltage modulation rates for controlling the first switch set 11, the second switch set 21 and the third switch set 31 respectively.
By means of the aforesaid mode control means, the first winding set AW, the second winding set BW and the third winding set CW can be combined to form an H type mode for driving the motor.
In the H type mode, by means of the symmetrical relationship between the first, second and third upper windings AW1,BW1,CW1 and the first, second and third lower windings AW2,BW2,CW3, the electric current flowing from each winding through the common contact P to the other windings is zero (i=0), as shown in
If you wish to combine the first winding set AW, the second winding set BW and the third winding set CW into a Y type mode, the operation is outlined hereinafter.
The synchronous action and complementary action in the mode control means are same as the aforesaid H type mode.
However, the mode control means does not control the terminal voltage or voltage modulation rate of the first switch set 11, the second switch set 21 and the third switch set 31 respectively. It employs the known field oriented control (FOC) technique to control the pulse width modulation status of each power electronic switch S1˜S12.
By means of the aforesaid mode control means, the first winding set AW, the second winding set BW and the third winding set CW can be combined to form a Y type configuration for driving the motor, wherein the aforesaid complementary action enables each upper winding to provide an electric current to the other upper windings, or enables each upper winding to provide an electric current to the other lower windings, considering the combination of the winding sets as a Y type configuration. The operation of this Y type configuration will be described latter in conjunction with the annexed drawings.
When assembling the motor, the first winding set AW, the second winding set BW and the third winding set CW are respectively mounted in respective stator grooves. The number of the stator grooves should be a multiple of 3, matching the number of the three upper windings or three lower windings.
Further, in this embodiment, sinusoidal drive configuration or square wave drive configuration is selected for pulse width modulation. If square wave drive configuration is selected, six-step square wave drive configuration can be employed. If sinusoidal drive configuration is selected, sinusoidal pulse width modulation (SPWM) or space vector pulse width module (SVPWM) can be employed.
The following Table I shows an example of the application of six-step square wave drive configuration to drive each power electronic switch. This drive configuration can be used in an H type configuration to drive the motor.
In the case where the first winding set AW is phase A, the second winding set BW is phase B and the third winding set CW is phase C, the drive configuration is illustrated in
Normally, the motor mutual inductance (M) is low and can be decoupled, and therefore, control blocks ib and it can be provided, in which:
i
a
*=I sin ωet
i
b
*=I sin(ωet−120°)
i
c
*=I sin(ωet−240°).
At this point we can see that the sinusoidal drive method illustrated in
In the case for Y type configuration control, field oriented control (FOC) techniques can be employed to control the pulse width modulation of each power electronic switch. Under the architecture of the first, second, fifth, sixth, ninth and tenth power electronic switches S1,S2,S5,S6,S9,S10, the Y type configuration thus formed is as illustrated in
From the above we can see that the structure of the present invention is totally different from the prior art techniques, it changes the motor drive mode by means of controlling the on/off status of each switch.
