Motor apparatus

Details Motor apparatus Motor apparatus

2001-02-13

2003-03-25

Nappi, Robert E. (Department: 2837)

Electricity: motive power systems

Switched reluctance motor commutation control

C318S132000, C318S139000, C318S432000, C318S434000, C318S434000, C318S799000, C318S800000

Reexamination Certificate

active

06538404

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention concerns a DC brushless motor apparatus allowing to control the inverter circuit driving by position detection signal obtained through the position detection of a motor apparatus, particularly.
2. Background of the Invention
As for the composition of such DC brushless motor apparatus, for example, compositions as shown in
FIG. 9
,
21
,
30
are disclosed by Japan Patent Application Laid-Open Hei 8-182378. In
FIG. 9
,
21
,
30
, the power source section
1
,
11
,
21
is a DC power source, and obtains an bus voltage Vcc of the inverter circuit
2
,
12
,
22
for obtaining a pulse modified voltage mentioned below, and obtains a DC power source, for example, by rectification and flattening of the AC power source.
In
FIG. 9
, the inverter circuit
2
, generates multi-phase, for instance, three-phase pulse width modified voltage of U-phase, V-phase and W phase, by controlling transistors TrU~TrZ, for instance, power transistor, IGBT device or the like, by means of driving signal from the drive circuit
4
, creates a rotational magnetic field, and rotates the rotor
3
R by supplying respective stator coils
3
U,
3
V,
3
W of the DC brushless motor
3
. Though not illustrated, the rotor
3
R is composed of a plurality of magnetic poles, for example, by magnetizing two pairs of N pole and S pole, as necessary, an embedded magnet type rotor as mentioned in
FIG. 12
below is employed. In this invention, besides magnetic pole formed as rotor and then magnetized, and magnetic pole formed by embedding or fitting a permanent magnet in a rotor, the “magnetic pole” includes also those formed by the other methods.
The driving of transistors TrU~TrZ by the drive circuit
4
is as shown by [Transistor driving waveform] in
FIG. 10
; fine pulse waveform portions correspond to chopping portions, and the voltage output to the terminal R of U phase, terminal S of V phase and terminal T of W phase appear, for instance, as waveforms before the partial voltage of [Terminal voltage partial voltage waveform] in
FIG. 10
, FIG.
11
.
Here, as U phase, V phase and W phase are alternative current, from the time sequence viewpoint, U phase→V phase→W phase→U phase→V phase→W phase . . . are repeated, for V phase, U phase is the preceding phase, and W phase is the following phase, and for W phase, V phase is the preceding phase, and U phase is the following phase, and further, for U phase, W phase is the preceding phase, and V phase is the following phase.
Consequently, divided by the bleeder circuit of the resistor Rau, Rbu, bleeder circuit of the resistor Rav, Rbv and bleeder circuit of the resistor Raw, Rbw, the waveform of respective voltages input to respective positive terminals, namely respective + terminals of the comparator CPu, comparator CPv and comparator CPw result in U phase partial voltage Ua, V phase partial voltage Va and W phase partial voltage Wa having a waveform like U phase, V phase and W phase of [Terminal voltage partial voltage waveform] in FIG.
10
.
The voltage waveform of the imaginary neutral point voltage E
0
input to respective negative terminals, namely − terminals of the resistance comparator CPu, comparator CPv and comparator CPw, by dividing the buss voltage Vcc with the bleeder circuit of the resistor Rd, Rc is as shown by [Power source voltage partial voltage waveform (imaginary neutral point voltage) in FIG.
11
. Here, the imaginary neutral point voltage E
0
is positioned substantially at the center of the amplitude of U phase partial voltage Ua, V phase partial voltage Va and W phase partial voltage Wa, be setting the resistor Rd, Rc so that [Rb/(Ra+Rb)]=[2Rd/(Rc+Rd)] for respective resistors Ra~Rd in respective bleeder circuit of U phase, V phase and W phase.
Then, the comparator CPu becomes U phase position detection comparator, the comparator CPv V phase position detection comparator, and the comparator CPw W phase position detection comparator, and respective transistor TrU~TrZ of the inverter circuit
2
are driven by delivering the position detection signal Su, Sv and Sw obtained by detecting with respective comparator CPu, CPv and CPw to the control processing portion comprising mainly a microcomputer, namely to the microcomputer
5
, by controlling the drive circuit
4
through a predetermined control by the microcomputer
5
.
When the rotor
3
R rotates, as an induction voltage appears at the stator coil of the phase not conducted with pulse amplitude modified voltage among the stator coils
3
U,
3
V and
3
W, [Rising induction voltage] and [Falling induction voltage] appear after respective spike voltage, as shown in the same drawing.
Then, respective comparator CPu, CPv and CPw detect the intersection with said neutral point voltage in the portion of [Rising induction voltage] and [Falling induction voltage], namely zero cross point P by comparing these voltages, and output this detection signal as position detection signal.
For instance, taking the comparison detection state by the comparator CPu as example, it is as [U phase position detection comparator positive negative input voltage (overwrite)] of
FIG. 11
, and the zero cross point P is detected, and “U phase rising position detection point” and “U phase falling position detection point” are output as position detection signal, as [U phase position detection comparator output voltage] in FIG.
11
. Here, the comparison detection state by the other comparator CPv, CPw is the waveform state, in which the waveform of [U phase position detection comparator positive negative input voltage (overwrite)] of
FIG. 9
is shifted by the phase of 120 degrees.
Such DC brushless motor has an advantage of effective use of reluctance torque by performing weak field control, by using an embedded magnet type rotor, namely IPM type rotor as shown in
FIG. 12
; however, when this IPM rotor is used, a flat portion DX flat in the proximity of the zero cross point P is generated in the induction voltage waveform, making the position detection unstable. as shown in FIG.
13
.
Therefore, Jpn. Pat. Appln. Publication Laid-Open No. HEI 11-146685 discloses a composition, wherein, a vertical variation type imaginary neutral point voltage is generated by further adding a plurality of resistors Rf, Rh at the portion where the bus voltage Vcc is divided by respectively equal resistance value resistors Rd, Rc, and alternatively short-circuiting these additional points by respective switching device Tra, Trb according to the control signal from the microcomputer
5
, and wherein the zero cross point P is shifted to a position off said flat portion Dx, by comparing and detecting the intersection of this vertical variation type imaginary neutral point voltage and the aforementioned [Rising induction voltage] and [Falling induction voltage] by means of respective comparator CPu, CPv, CPw.
In addition, Jpn. Pat. Appln. Publication Laid-Open No. HEI 11-146685 or the like disclose a composition (called, no chopping composition, hereinafter) wherein the detection is performed by a detection composition similar to said respective position detection, by modifying to the waveform like
FIG. 15
, without performing the pulse amplitude modification by said chopping.
Such prior art required, disadvantageously, to dispose a switching device, and a composition to control its driving.
On the other hand, in
FIG. 21
, the inverter circuit 12 rotates the rotor
13
R by generating a multi-phase, for instance, three-phased pulse amplitude modified voltage of U phase, V phase and W phase by controlling the transistor TrU~Trz, for example power transistor, IGBT device or the like, with driving signal from the drive circuit
14
, and generating a rotary magnetic field by imparting to respective stator coils
13
U,
13
V and
13
W of the DC brushless motor
13
. Though not illustrated,

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