JP2003189667A - Motor control method and motor employing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce dimensions of a battery and extend an operation time of a motor using the battery by utilizing a regenerative power of a motor when the motor is in a PWM control state. <P>SOLUTION: When a motor 3 is subjected to the PWM control by an inverter circuit 2, if the motor 3 is in an accelerating operation state or in a steady operation state, the PWM is introduced only in the upper stage or in the lower stage of the inverter circuit 2 and, if the motor 3 is in a decelerating operation state, the PWM is introduced in both the upper and lower stages. With such a constitution, the power consumption of a battery 1 can be suppressed, the dimensions of the battery 1 can be reduced, and the operation time of the motor can be extended. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling a motor used in electric equipment such as an electric vacuum cleaner and a motor operated by the control method.

[0002]

2. Description of the Related Art In recent years, an increasing number of motors driven by inverter circuits use a battery power source.

When the speed of a motor driven by an inverter circuit is controlled by PWM, it is common to perform PWM only on the upper stage or the lower stage of the inverter circuit.

The details will be described below with reference to the circuit diagram and the energization timing diagram of the drive circuit of the motor driven by the conventional control method of the inverter circuit.

FIG. 3 is a drive circuit diagram of a motor driven by a conventional inverter circuit control method, and FIG.
In the conventional control method of the inverter circuit, only the lower stage has PW
FIG. 7 is a timing chart of energization when M is performed.

In FIG. 3, reference numeral 1 is a battery serving as a power source of the motor 3, 2 is an inverter circuit for driving the motor, and 3 is a motor having windings of three phases of U phase, V phase and W phase. The inverter circuit 2 has a switching element Tr1.
~ Tr6 and diodes D1 to D6,
It is driven by the control circuit 5 based on the rotor position signal 4 of the motor 3. Drive circuit according to the speed command signal 6,
PWM control is performed by the PWM circuit 5 to realize acceleration / deceleration of the motor 3.

In PWM, Tr1 is ON and Tr in PWM
4 represents the U-phase and V-phase current flows of the motor when OFF, and corresponds to the section b in FIG. The current flow 8 becomes Tr1 → U phase winding → V phase winding → D3 → Tr1 and it can be seen that the regenerative power of the motor 3 does not return to the battery 1.

[0008]

In a motor driven by an inverter circuit such as a brushless motor, the use as a battery power source is increasing, and the battery is downsized,
It is required to extend the operation time of the motor with battery power.

An object of the present invention is to reduce the size of a battery and extend the operating time of a motor with a battery power source by effectively utilizing the regenerative power during PWM control of the motor.

[0010]

In order to solve the above-mentioned problems, a motor control method of the present invention provides an inverter when the motor is PWM-controlled by an inverter circuit during acceleration or steady operation of the motor. Only the upper and lower stages of the circuit are PWM, and the upper and lower stages of the inverter circuit are PWM during the deceleration operation of the motor. According to the above motor control method, it is possible to reduce the switching loss of only one side of the upper stage or the lower stage during acceleration operation requiring steady work of the motor and steady operation speed, and it is possible to suppress the power consumption of the battery. . Further, during deceleration operation, the regenerative electric power of the motor can be returned to the battery in the period where the PWM of the inverter circuit is OFF, so that the battery can be downsized and the operating time of the motor can be extended.

[0011]

1 is a block diagram showing an inverter circuit for driving a motor according to a first embodiment of the present invention.
This is a control method characterized by M control, and PWM control for both upper and lower stages during deceleration operation of the motor. PWM is applied to only one side of the upper or lower stage during acceleration operation requiring steady work of the motor and steady operation speed. Thus, the switching loss can be reduced, and the regenerative power of the motor in the OFF section of the PWM of the inverter circuit can be returned to the battery during the deceleration operation.

According to a second aspect of the present invention, there is provided an inverter circuit driven motor using the motor control method according to the first aspect of the present invention, which reduces switching loss during acceleration operation and steady operation and reduces battery life. The power consumption can be suppressed, and the battery can be charged with regenerative power during deceleration operation.

According to a third aspect of the present invention, there is provided an electric device on which the motor according to the second aspect is mounted, and it is possible to reduce the size of the battery and extend the operating time of the device.

[0014]

Embodiments of the motor control method of the present invention will be described below.
Specific examples thereof will be described with reference to the drawings.

FIG. 1 is a drive circuit diagram of a motor driven by the control method of the present invention, and FIG. 2 is a PW in both the upper and lower stages in the control method of the inverter circuit of the present invention.
FIG. 7 is a timing chart of energization when M is performed.

In the circuit configuration of the motor driven by the control method of the present invention shown in FIG. 1, 1 is a battery serving as a power source of the motor, 2 is an inverter circuit for driving the motor, 3 is a U phase, V phase, W A motor having three-phase windings of three phases.

The inverter circuit 2 includes switching elements Tr1, Tr3 and Tr5 in the upper stage and a diode D in the upper stage.
1, D3 and D5, and the lower switching element T
r2, Tr4 and Tr6 and lower diodes D2 and D
4 and D6, a drive circuit, P, and P in accordance with the speed command signal 6 based on the rotor position signal 4 of the motor 3.
It is driven by the WM circuit 5.

In the above structure, only the upper stage or the lower stage of the inverter circuit is PWM during the acceleration operation or the steady operation of the motor, and the upper and lower stages of the inverter circuit are PWM during the deceleration operation of the motor.

7 indicates that Tr1 is turned off when the motor is decelerated.
The flow of the U-phase and V-phase currents of the motor when FF and Tr4 are turned off is shown and corresponds to the section a in FIG.

The current flow 10 is: battery → D2 → U
Phase winding → V phase winding → D3 → battery and regenerative electric power of the motor 3 can be returned to the battery 1.

[0021]

As described above, according to the present invention,
When performing the PWM control of the motor in the inverter circuit, only the upper stage or the lower stage of the inverter circuit is set to PWM during the acceleration operation or the steady operation that requires the work of the motor. By doing so, switching loss can be reduced during acceleration operation and steady operation, and battery power consumption can be suppressed, and regenerative power can be charged to the battery during deceleration operation, which reduces battery size and motor operating time. Can be extended.

[Brief description of drawings]

FIG. 1 is a drive circuit diagram of a motor in a control method according to an embodiment of the present invention.

FIG. 2 shows P in a control method according to an embodiment of the present invention.
Energization timing chart at WM

FIG. 3 is a motor drive circuit diagram according to a conventional control method.

FIG. 4 is a timing chart of energization during PWM in the conventional control method.

[Explanation of symbols]

1 battery 2 Inverter circuit 3 motor 4 Rotor position signal 5 Drive circuit, PWM circuit 6 Speed command signal 7 Current flow when Tr1 is ON and Tr4 is OFF

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Katsutoshi Fujita             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 5H007 BB01 BB06 CA01 CB05 DB01                       EA02                 5H560 AA10 BB04 BB12 DA17 EB01                       EB07 EC02 EC09 HB02 SS02                       UA02 XA12

Claims (3)

[Claims] 1. An inverter circuit for driving a motor is characterized in that only the upper stage or the lower stage is PWM controlled during acceleration operation or steady operation of the motor, and both upper and lower stages are PWM controlled during deceleration operation of the motor. Motor control method. 2. A motor driven by an inverter circuit, wherein the motor control method according to claim 1 is used. 3. An electric device on which the motor according to claim 2 is mounted.