JPS63249488A - Vacuum cleaner - Google Patents

Abstract

PURPOSE:To improve the suction performance of a vacuum cleaner by using an inverter-controlled brushless DC motor for the cleaner, controlling a closed loop current and correcting a current command from a rotating speed. CONSTITUTION:An inverter controller 10 obtains a DC voltage Ed by 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. Further, the command is corrected according to rotating speed to control the motor optimally in accordance with the load change of the cleaner by increasing the rotating speed varying range.

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 shortening the life of the brushes.

As a countermeasure to this problem, an electric blower using a brushless DC motor has been proposed as described in Japanese Patent 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 load condition of the vacuum cleaner.

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

[Means for solving problems]

The above object is achieved by performing closed-loop current control on the brushless DC motor using an inverter control device based on a speed command, and further correcting the speed command according to the rotational speed of the motor.

[Effect]

The brushless DC motor is a synchronous motor that uses a permanent magnet for the field, but since the inverter control device performs closed-loop current control of the 71 motor based on the speed command, the rotation speed will vary depending on the load change of the vacuum cleaner. It changes squarely, resulting in a direct winding characteristic.

Furthermore, by correcting the speed command according to the number of revolutions, the range of change in the number of revolutions becomes larger, allowing optimal motor control in response to changes in the vacuum cleaner's load, improving suction performance, and increasing the speed of the vacuum cleaner. 1! ) can be done.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

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 includes an AC power source 14 and a 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
120 consisting of s and freewheeling diodes D1 to DB.
It is a current-carrying type inverter, and its AC output voltage is a DC voltage E (1 positive potential side transistors T R1 to T R3
The current flow period (120 electrical degrees) is controlled by chopper operation under pulse width modulation.

Furthermore, a low resistance R1 is connected between the common emitter terminals of the transistors TRa to TRe and the common anode terminals of the freewheeling diodes D4 to D6.

The brushless DC motor 9 consists of a rotor 9-2 and a stator into which an armature winding 9-1 is inserted using a two-pole permanent magnet as a field, and the winding current flowing through the armature winding 9-1 is as described above. Since the voltage also flows through the low resistance R1, the load current Io 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
A magnetic pole position detection circuit 12 that receives the output from the Hall element 11 and detects the Mt12 position of the rotor 9-2 of the microcomputer 132. Load current T from voltage drop of low resistance R1
A current detection circuit 17 that detects the value of o. transistor T
Pace driver 19 that drives R1 to T Ra. It consists of a speed command circuit 18 that transmits the speed to be U based on a microcomputer 13.

The 6J1+1 detection circuit 12 is a circuit that receives the output from the Hall element 11 and forms a position detection signal L2S corresponding to the position of one rotor. Then, this position detection signal 12S
The rotational speed of the brushless DC motor 9 is calculated and determined by the microcomputer 13 using .

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 contains various processing programs necessary to drive the brushless DC motor 9.

For example, information related to speed calculation processing, command import processing, speed control processing, etc. is stored.

On the other hand, the above-mentioned RAM is made up of a storage section for reading/writing various data necessary for executing the above-mentioned various processing programs.

The transistors T Rs to T Ro receive the firing signal 13s from the microcomputer 13 and start the pace driver 19.
Driven by. Note that the current command circuit 21 forms a chopper signal as described later. That is,
In a brushless DC motor, the winding current flowing through the armature winding corresponds to the motor's output of 1-lux, and by controlling the single winding current for each magnetic pole position, continuous control of the output torque is possible. It is.

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 command import processing to determine the speed command N*, and outputs the current command ■D* with a gain of 1. . This current command Io1 is input to the D/A converter of the current command circuit 21, this output is compared with the output of the triangular wave generation circuit by a comparator, and the output is input to the pace driver 19 and applied to the brushless DC motor 9. The voltage to be applied is determined. Then, the output of the current detection circuit 17 is input to the microcomputer 13, and the microcomputer 13 calculates the load current Io and compares it with the command value D*. As a result, the brushless DC motor 9 is always controlled to follow the current command IO.

Furthermore, in response to the signal from the magnetic pole position detection circuit 12, the microcomputer 13 performs speed calculation processing to obtain the reference value N.
The difference (N - N 1 ) with respect to 1 is determined, AID is determined with a gain of 2, and the AID is compared with the current command ■D*. As a result, the current command ■D* of the brushless DC motor 9 is corrected according to the value of the rotation speed N corresponding to the load change (in other words, the speed command is corrected), and based on this new current command ■D* -ΔIn. Since it is operated under closed-loop current control (this control is referred to as series control), the variable range of the rotation speed becomes large.

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 POIIL + represents the rotational speed N of the motor and the load current Io, and the range from the maximum operating point to the minimum operating point is the operating range of the vacuum cleaner. The chain line shows the case when the electric motor is operated under normal closed-loop speed control, and since the rotation speed N is constant with respect to changes in the air volume Q, the suction power Pout is small and the required performance as a vacuum cleaner can be obtained. do not have. On the other hand, the solid line shows the case where the motor is operated with the closed loop current control of the present invention, and the wind ftQ
When Pout decreases, the load torque also decreases, so when closed-loop current control is performed, the rotation speed N increases squarely as the wind ff1Q decreases, so the suction power Pout is large and the required performance as a vacuum cleaner can be obtained. . Furthermore, the dashed-dotted line indicates the case where the motor is operated with the series winding control of the present invention,
Based on the rotation speed N1, the current correction amount ΔIn is calculated from the increase in the rotation speed N with respect to the change in the air volume Q (N
It is possible to suppress the increase in rotation speed N due to changes in Q,
Direct winding characteristics can be achieved. By setting this current correction amount ΔIn arbitrarily, the range of change in the rotational speed N can be expanded. As a result, it is possible to arbitrarily adjust the suction power Pouc by expanding the variation range of the rotation speed, and it is possible to obtain a vacuum cleaner with improved suction performance. [Effects of the Invention] According to the present invention, an inverter-controlled brushless DC motor is used as the drive source of a vacuum cleaner, closed-loop current control is performed based on a current command, and the current command is further corrected according to the rotation speed. As a result, there is an effect that a vacuum cleaner with arbitrary suction performance and improved suction performance can be obtained by optimal electric 6'JJ machine control according to load changes of the vacuum cleaner.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing in block form a control circuit of a speed control device according to an embodiment of the present invention, and FIG. 2 is an overall configuration diagram of the speed control device consisting of a brushless DC motor and an inverter control device 6. FIG. 3 is a performance curve diagram of the vacuum cleaner according to the present invention. 9 - Brushless DC motor, 10... Inverter control device, 11... Holle element, 12... Magnetic pole position detection circuit, 13... Microcomputer, 17... Current detection circuit, 18... Speed command Circuit, 19... Pace Done 2 Color IQ,... I;

Claims (1)

[Claims] 1. In a drive source that uses a brushless motor and an inverter speed control device for driving the same, the inverter speed control device includes a microcomputer, a current detection circuit, a magnetic pole position detection circuit, and a speed command circuit. A vacuum cleaner characterized in that the brushless electric motor is controlled in a closed loop based on a speed command from a speed command circuit. 2. The vacuum cleaner according to claim 1, wherein the brushless electric motor is configured to perform series winding control according to the actual rotation speed.