JPS63249489A - Vacuum cleaner - Google Patents

Abstract

PURPOSE:To prevent resping noise by using an inverter-controlled brushless DC motor for a vacuum cleaner, controlling a closed loop speed, correcting a speed command from a load circuit, and delaying the timing of the correction amount. CONSTITUTION:An inverter controller 10 obtains a DC voltage Ed through a rectifier 15 and a smoothing condenser 16 from an AC power source 14, and drives a brushless DC motor 9 through an inverter 20. The speed controller of the motor 9 is composed of a microcomputer 13, a pole position detector 12 for a rotor 9-2, a load current ID detector 17, a base driver 19, a speed command circuit 18, etc. The controller 10 controls the motor 9 by a closed loop current on the basis of a speed command, and, the command is corrected according to load current value of the motor 9. Further, a correction amount corresponding to the load current value is delayed at its timing. Thus, the abrupt change of the rotating speed of the motor 9 can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vacuum cleaner, and more particularly to a speed control device for an electric motor serving as a drive source for the vacuum cleaner.

[Conventional technology]

An electric blower consisting of a fan and an AC commutator is used as the drive source for a vacuum cleaner. However, it involves mechanical sliding between a brush and a commutator, and with the recent trend toward smaller size and lighter weight due to higher speeds, commutation conditions have become stricter, causing sparks to be generated from the brushes and resulting in a shortened brush life.

As a countermeasure against this problem, an electric blower using a brushless DC motor has been proposed as described in Japanese Patent Application Laid-Open No. 60-242827. However, no consideration has been given to a speed control method for brushless DC motors suitable for vacuum cleaners.

[Problem that the invention seeks to solve]

The above-mentioned conventional technology does not consider the speed control method of a brushless DC motor suitable for a vacuum cleaner, and has the problem of not being able to respond to changes in the Wi vacuum cleaner load state.

An object of the present invention is to perform optimal speed control of a brushless DC motor depending on the load condition of a vacuum cleaner.

[Means for solving problems]

The above purpose is to perform closed-loop speed control of a brushless DC motor using an inverter control device based on a speed command, further correct the speed command according to the load current value of the motor, and delay this correction amount in time. ,
achieved.

[Effect]

A brushless DC motor is a synchronous motor that uses a permanent magnet for the field, and an inverter control device performs closed-loop speed control of the motor based on a speed command, and also corrects the speed command according to the load current value of the motor. By this,
Direct winding characteristics can be achieved.

Furthermore, by temporally delaying the amount of correction according to the load current value, sudden changes in the rotational speed of the motor can be suppressed, thereby preventing noise caused by changes in the rotational speed during cleaning.

〔Example〕

Conventionally, AC commutator motors using mechanical carbon brushes have been mainly used as electric motors for vacuum cleaners. However, in response to demands for higher speeds and higher performance, electric motors that are driven by inverters and do not require the brushes have been proposed.

Examples of electric motors that are not equipped with brushes and can be driven by an inverter include brushless DC motors, induction motors, reluctance motors, and even hysteresis motors, all of which can be used as vacuum cleaner motors. be.

Although the present invention is thus applicable to any electric motor drive device, for convenience, a brushless DC motor driven by an inverter will be described as an example of the present invention.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

FIG. 2 shows the overall configuration of a speed control device comprising a brushless DC motor and an inverter control device according to the present invention.

The inverter control device 10 connects the AC power source 14 to the rectifier circuit 1.
5 and the smoothing capacitor 16, the DC voltage Ed shown in the figure is obtained and supplied to the inverter 20.

This inverter 20 includes transistors TR1 to TR
This is a 120 degree conduction type inverter consisting of a freewheeling diode D s = De
It is assumed that the conduction period (120 electrical degrees) of Ra is controlled by chopper operation under pulse width modulation.

Furthermore, a low resistance R1 is connected between the common emitter terminals of the transistors TR4 to TRB and the common anode terminals of the freewheeling diodes D4 to Da.

The brushless DC motor 9 consists of a rotor 9-2 whose field is a two-pole permanent magnet and a stator into which an armature winding 9-1 is inserted, and the winding current flowing through the armature winding 9-1 is as follows. Since the voltage also flows through the low resistance R1, the load current IQ of the motor 9 can be detected by the voltage drop across the low resistance R1.

The control circuit that controls the speed of the brushless DC motor 9 is
Microcomputer 13. A magnetic pole position detection circuit 12 that receives the output from the Hall element 11 and detects the magnetic pole position of the rotor 9-2. Current detection circuit 17 that detects the value of load current Io from the voltage drop across low resistance R1. Transistor T R1
A pace driver 19 that drives the ``-T Re'' is composed of a speed command circuit 17 that transmits a reference speed to the microcomputer 13.

The magnetic pole position detection circuit 12 is a circuit that receives the output from the Hall element 11 and forms a position detection signal 12S corresponding to one rotor position. Then, using this position detection signal 12S, the rotational speed of the brushless DC motor 9 is calculated and determined by the microcomputer 13.

The current detection circuit 17 is a circuit that detects the load current Io in response to a voltage drop across the low resistance R1, and forms a current detection signal 17S using an A/D converter (not shown) or the like.

Further, the microcomputer 13 includes a CPU, R
It is composed of OM, RAM, etc., and is connected to each other by an address bus, a data bus, and a control bus (not shown).

The ROM stores various processing programs necessary to drive the brushless DC motor 9, such as speed calculation processing, command acquisition processing, speed control processing, and the like.

On the other hand, the RAM mentioned above is composed of a storage section for reading and writing various data required when executing various processing programs described in iw.

The transistor T Rs '' T Ra receives an ignition signal 13S from the microcomputer 13 and is driven by the pace driver 19.The voltage command circuit 21 forms a chopper signal as described later.

In other words, in a brushless DC motor, the winding current flowing through the armature winding corresponds to the output torque of the motor, and by controlling the winding current for each rotor position, continuous control of the output torque is possible. It is something.

FIG. 1 is a schematic block diagram showing the control circuit of the present invention. In the figure, when a command is input from the speed command circuit 18 to the microcomputer 13, the microcomputer 13 performs a command acquisition process and outputs a speed command N. This speed command N skewer is converted to D/ of the voltage command circuit 21.
This output is input to the A converter, this output is compared with the output of the triangular wave generation circuit by a comparator, and the output is the pace driver 1.
9 and the voltage applied to the brushless DC motor 9 is determined. Then, upon receiving the signal 12S from the magnetic pole position detection circuit 12, the microcomputer 13 performs speed calculation processing, calculates the number of rotations N, and compares it with the command value N. As a result, brushless DC power!
I! The JJ machine 9 is always controlled to follow the speed command N.

Furthermore, the output 17S of the current detection circuit 17 is input to the microcomputer ]-3, the microcomputer 13 calculates the load current IO, and calculates the difference (Ior-3) from the reference value IDI.
Io) is calculated, ΔN is calculated using the gain, delay processing is performed, and the result is added to the speed command N. As a result, the speed command N- of the brushless DC motor 9 is corrected with a time delay depending on the value of the load current Io corresponding to the load change, and the brushless DC motor 9 is operated under closed-loop speed control based on this new speed command N-+ΔN. Since the rotational speed increases as the load current In decreases, a series winding characteristic can be achieved, and sudden changes in the rotational speed can be prevented, a vacuum cleaner with suppressed noise and improved suction performance can be obtained.

Figure 3 shows the performance curve of a vacuum cleaner in which a brushless DC motor is driven by the speed control device of the present invention.The horizontal axis represents the air volume Q passing through the vacuum cleaner, and the vertical axis represents the suction performance The suction power P. Uty represents the rotational speed and load current Io of the electric motor, and the range from the maximum operating point to the minimum operating point is the operating range of the vacuum cleaner. From this, the brushless direct current motor has series winding characteristics with respect to changes in the wind ff1Q.

FIG. 4 shows changes in the rotational speed with respect to changes in the state of the mouthpiece, where the chain line shows the case without delay processing and the solid line shows the case with delay processing of the present invention. From this, without a delay circuit, the motor rotation speed N would fluctuate rapidly with respect to time t depending on the load condition (when the user is cleaning by moving the suction mouth back and forth)
At this time, the sound waves as the rotation speed changes, creating a harsh noise. On the other hand, with a delay circuit, the change in rotational speed is delayed with respect to time, and rapid fluctuations in rotational speed can be suppressed, which has the effect of preventing harsh noise.

〔Effect of the invention〕

According to the present invention, an inverter-controlled brushless DC motor is used as the drive source of the vacuum cleaner, closed-loop speed control is performed based on a speed command, and the speed command is corrected according to the load current, and the amount of correction is changed over time. By delaying the rotation speed, rapid fluctuations in the rotation speed can be suppressed, which has the effect of providing a vacuum cleaner that does not generate harsh noise.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram showing a control circuit for driving a brushless DC motor according to the present invention, and FIG. 2 is an overall configuration diagram of a speed control device comprising a brushless DC motor and an inverter control device according to the present invention. FIG. 3 is a performance curve diagram of the vacuum cleaner, and FIG. 4 shows changes in the rotational speed with respect to changes in the state of the suction port. 9... Brushless DC motor, 10... Inverter control device, 11... Hall element, 12... Magnetic pole position detection circuit, 13... Microcomputer, 18...
・Speed command circuit, 19... Pace driver, 20...
- Inverter, 21...voltage command circuit. Pavilion 2

Claims (1)

[Claims] 1. In a vacuum cleaner using an electric motor as a drive source and a speed control device for variable speeding the electric motor, the speed control circuit includes a microcomputer, a speed detection circuit, a current detection circuit, and a speed command circuit. . A vacuum cleaner characterized in that the microcomputer is configured to control the speed of the electric motor, the speed command is corrected by a load current value, and this correction has a time delay. 2. The vacuum cleaner according to claim 1, wherein the electric motor is a brushless DC motor, and the speed control device is a closed-loop speed control using an inverter control device.