JP3427001B2 - Drive device for brushless motor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects a change in an induced voltage generated in a stator winding that has a plurality of permanent magnets and is not energized by rotation of a rotor. Further, the present invention relates to a brushless motor driving device in which a stator winding to be energized is sequentially switched based on the detection signal. 2. Description of the Related Art As a prior art of a motor driving device,
There is one described in Japanese Patent Application Laid-Open No. 7-147795. The starting method of the brushless motor described in this publication and the like is started by synchronous operation in which the energization to the stator winding is sequentially switched, gradually increasing the energization cycle, and increasing the rotor speed to a predetermined speed, The operation was switched to a position detection operation based on the induced voltage. In the method of starting a brushless motor disclosed in the above publication, the rotor position is unknown at the time of starting and is not always the same. When energization is started from the beginning, the combination of the stator windings to start energization is not always appropriate, and the rotor cannot be reversed, or depending on the state of the load torque, cannot be drawn into the synchronous operation. There is a risk of not being able to start. In addition, when starting is failed and restarting is performed, energization is started from the same combination of stator windings as when starting is failed, so there is a possibility that the same failure in starting will be repeated. An object of the present invention is to provide a brushless motor starting device in which the starting of the motor is improved. In order to solve the above-mentioned problems, a rotor having a plurality of permanent magnets and a plurality of stator windings arranged to apply a rotating magnetic field to the rotor when energized are provided. A plurality of stator windings of the plurality of stator windings, and a rotating magnetic field is obtained by energizing some of the stator windings. In a brushless motor drive device configured to detect the change of the stator winding and sequentially switch the stator winding to be energized based on the detection signal, when the motor cannot be started normally and restarted, the motor starts normally. The configuration is such that the first energization is started from the combination of the stator windings that has been formed many times. Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a control block diagram of an embodiment of the present invention. The AC power supply 1 is connected to a brushless motor 5 via a semiconductor switching element 4 rectified by a rectifier circuit 2 and connected in a three-phase bridge. The microprocessor 7 includes a position detecting circuit 6
Then, based on a rotor position detection signal obtained by detecting a change in induced voltage from each motor terminal, a drive signal is supplied to a drive circuit so as to sequentially switch the stator windings to be energized. When starting a brushless motor, FIG.
As shown in (1), the combination of the stator windings is stored in the microprocessor in advance as an energization pattern, energization is started from energization pattern 1, the energization pattern is sequentially switched, and the stopped rotor is rotated. Here, the energizing pattern to be energized first at the time of starting is not the same energizing pattern, but is, for example, from energizing pattern 1 at the first start and energizing pattern 2 at the next start.
Each time the engine is started, the energization pattern to be energized first is changed. The pattern to be energized first may be selected in order from pattern 1 to pattern 6 or may be selected as shown in FIG. 3 or randomly. When energization starts from energization pattern 1 and fails to start, and restarts, the same energization pattern l
Instead, the energization is started from another energization pattern (for example, energization pattern 2), thereby preventing the same start failure from being repeated. Further, if it fails to start, the first energization pattern when the start fails is stored in the memory of the microprocessor, is not performed starting from the same energizing patterns as the case of failure. An example in which the selection of the energizing pattern to be energized first is performed in order from energizing pattern 1 to energizing pattern 6 will be described as an example. When starting for the first time, energization is started from energization pattern 1. When the engine is started next, energization is started from the energization pattern 2, and thereafter, every time the engine is started in the same manner, patterns 1 to 6 are sequentially selected. Here, when the energization is started from the energization pattern 1 and the start fails, the pattern 2 to the pattern 6 are sequentially selected so as not to start the energization from the energization pattern 1. In other words, by not starting to start energizing from the same energizing pattern as when starting has failed,
Prevents repeated start failures. If the number of failures in starting is large, the number of failures and the energization start pattern at that time are stored in a memory in the microprocessor. The probability of doing so can be reduced. As a result, the starting can be made good. As described above, according to the brushless motor driving apparatus of the present invention, when the number of failures in starting is large, the number of failures and the energization start pattern at that time are stored in the memory in the microprocessor. It is possible to store the current and start energization from an energization pattern with a small number of start failures, thereby reducing the probability of a start failure. As a result, the starting can be made good.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a control block diagram showing an embodiment of the present invention. FIG. 2 is an explanatory view showing an energization pattern of a stator winding to be energized. FIG. 3 is an explanatory diagram showing a relationship between the number of times of starting and an example of an energizing pattern for energizing first. [Description of Signs] 1 AC power supply 2 Rectifier circuit 3 Smoothing capacitor 4 Semiconductor switching element 5 3-phase DC brushless motor 6 Position detection circuit 7 Microprocessor 8 Drive circuit

Continuation of the front page (72) Inventor Tetsuo Nomoto 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Shin Shinno 2-5-2-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo (56) References JP-A-6-217759 (JP, A) JP-A-7-107777 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02P 6 / 18

Claims (1)

(57) [Claims] [Claim 1] Rotor having a plurality of permanent magnets and energization
Sometimes a rotor arranged to apply a rotating magnetic field to this rotor
And a plurality of stator windings, and among the plurality of stator windings,
Energizing several stator windings to obtain a rotating magnetic field.
, The rotation of the rotor to the stator windings that are not energized
The resulting induced voltage change is detected and based on this detection signal
Brass that switch the stator winding to be energized sequentially
In the drive system of the siles motor, the motor
When restarting is not possible because of starting, the number of times
Starting the first energization from a large number of stator winding combinations
A brushless motor driving device.