Electricity: single generator systems – Combined control of generator and driving means – Simultaneous control
Reexamination Certificate
1999-09-09
2001-03-06
Ponomarenko, Nicholas (Department: 2834)
Electricity: single generator systems
Combined control of generator and driving means
Simultaneous control
C322S022000, C290S04000F, C318S140000
Reexamination Certificate
active
06198256
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a control apparatus for a synchronous generator system for converting kinetic energy to electric power, and more particularly to a control apparatus which does not require to provide any sensor, such as an encoder, hole elements and so on, for detecting the position of rotating magnetic poles of a synchronous generator. Further, the present invention relates to a hybrid-type electric vehicle, to which the synchronous generator control apparatus as mentioned above is applied.
2. Description of Related Art
There is known a hybrid-type electric vehicle, in which an internal combustion engine as well as an electric motor and/or generator are used in combination as a driving power source, for the purpose of improving the fuel consumption and the exhaust gas purification. In such an electric vehicle, it is desired that an electric vehicle under the standstill state can be started only electrically.
By the way, as a motor or a generator for use in an electric vehicle of this kind, a synchronous type machine is usually utilized. As is well known, the positional relationship between a stator and a rotor thereof are necessary to be found, in order to operate the synchronous machine.
In a conventional control apparatus of this kind, there has been provided a position sensor for detecting the position of rotating magnetic poles of a synchronous machine. However, such a position sensor is very expensive, with the result that the whole cost of the control apparatus increases. Further, such a sensor also increases the size of the control apparatus as a whole.
To solve the problems as described above, the Japanese Patent Application laid-open No. 9-163507 (published Jun. 20, 1997) proposes a so called sensorless synchronous machine system, in which a control computer carries out a predetermined processing to presume the position of magnetic poles of a synchronous machine.
It is well known that the voltage induced across a winding of a certain phase has the phase difference of 90° from the magnetic flux produced by a magnetic pole. The prior art as disclosed in the JP-A-9-163507 utilizes the aforesaid known fact, and the control computer takes therein a signal concerning the induced voltage and executes a predetermined processing to presume the position of the magnetic poles.
However, the prior art as described above is on the assumption that the phase difference between the phase voltage and the magnetic flux is equal to 90°. This assumption is quite correct under the condition that a synchronous machine is not loaded. However, the phase difference does not become equal to from 90°, as a load current flows through the synchronous machine. Namely, the position of the magnetic poles can not presumed exactly under the loaded condition of the synchronous machine.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a control apparatus for a synchronous generator system, wherein A.C. electric power produced by a synchronous generator is converted by a converter into D.C. electric power, in which the position of magnetic poles of the synchronous generator can be sensed without using any expensive position sensor or the like even under the condition that the generator is loaded.
According to a feature of the present invention, voltage instructions (V
u
*, V
v
*, V
w
*) for controlling the converter are created by using a reference P* of power to be produced by the synchronous generator, currents (I
u
, I
v
) flowing through the synchronous generator and information (&thgr;
0
, &ohgr;
r
) concerning the position of magnetic poles of the synchronous generator. Further, the point, at which the voltage passes through zero, is detected. The information (&thgr;
0
, &ohgr;
r
) concerning the magnetic pole position is produced on the basis of the voltage instruction (V
u
*, V
v
*, V
w
*) and the power reference P* when the synchronous generator is under the generation mode, and on the basis of an output of the zero crossing point detection when the synchronous generator is under the stand-by mode.
According to another feature of the present invention, when the synchronous generator is under the generation mode, the information (&thgr;
0
, &ohgr;
r
) concerning the position of magnetic poles is calculated based on the power reference P* as well as the currents (I
u
, I
v
) flowing through the synchronous generator, instead of the voltage instruction (V
u
*, V
v
*, V
w
*).
As described above, according to the present invention, information concerning the position of magnetic poles of a synchronous generator, which is necessarily required for the operation thereof, can be calculated based on the information concerning the voltage or the current. Accordingly, a position sensor like an encoder becomes unnecessary, whereby a control apparatus for a synchronous generator becomes small in size and its manufacturing cost can be decreased. Further, the speed of processing, i.e., detection of the position of magnetic poles, can be much improved, compared with the conventional system.
The characteristic features as mentioned above are advantageous to an electric vehicle, because space for apparatuses is very limited and the high speed processing is required.
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patent: 5545928 (1996-08-01), Kotani
patent: 5550445 (1996-08-01), Nii
patent: 5726559 (1998-03-01), Taniguchi et al.
patent: 5798631 (1998-08-01), Spee et al.
patent: 5903061 (1999-05-01), Tsuzuki et al.
patent: 5994881 (1999-11-01), Miyazaki et al.
patent: 6127813 (2000-10-01), Tamagawa
patent: 6130486 (2000-10-01), Shimizu et al.
Kaneko Satoru
Masaki Ryoso
Matsudaira Nobunori
Miyazaki Taizou
Obara Sanshiro
Evenson, McKeown, Edwards & Lenahan P.L.L.C.
Hitachi , Ltd.
Ponomarenko Nicholas
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