Drive system for household appliances

• US 5,241,257 A
• Filed: 07/01/1992
• Issued: 08/31/1993
• Est. Priority Date: 04/17/1989
• Status: Expired due to Fees

• Current Assignee: Emerson Electric Company
• Original Assignee: Emerson Electric Company
• Inventors: Nordby, Craig J., O'Breartuin, Ciaran, Sood, Pradeep K., Venturini, Marco
• Primary Examiner(s): Shoop, Jr., William M.
• Assistant Examiner(s): Cabeca, John W.
• Application Number:
  US07/908,758
• Time in Patent Office: 426 Days
• Field of Search: 318/811, 318/803, 318/805, 318/807, 318/802, 318/798, 318/599, 68/12 R, 68/207, 363/41, 363/97, 363/132
• US Class Current: 318/811
• CPC Class Codes: D06F 2103/46 of the motor driving the drum
• CPC Class Codes: D06F 2105/46 Drum speed; Actuation of motors, e.g. starting or interrupting
• CPC Class Codes: D06F 34/08 Control circuits or arrangements thereof
• CPC Class Codes: D06F 37/304 Arrangements or adaptations of electric motors
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers

Abstract

A drive system for a household appliance incorporates an electric motor. A control panel allows the user of the appliance to select from among various performance options which the appliance is able to perform. A microprocessor, functioning as a first control unit, is responsive to the selections and to various appliance sensors monitoring operational status of the appliance to control the operation of various components within the appliance by which the selected options are performed. An AC-DC converter and inverter supply electrical power to the motor. A second control unit, operating at a relatively faster rate of speed than the microprocessor, controls the supplying of power to the electric motor to achieve proper operation thereof.

Claims

1. A drive system for use in a household appliance incorporating an electric motor, the appliance having selectors by which a user of the appliance selects from among various performance functions of the appliance, the appliance operating at least the electric motor in accordance with the selected function, the drive system comprising:

power means supplying electrical power to the motor, said power means including AC-DC conversion means connected to a source of electrical energy and DC-AC inversion means connected to said motor, an output of said AC-DC conversion means being supplied as an input to said DC-AC inversion means;

first control means responsive to the selectors and the operational status of the household appliance for controlling operation of the various components within the household appliance by which the selected functions are performed, said first control means including microprocessor means for supplying a first control signal to said DC-AC inversion means; and

,

second control means interconnected with said first control means and including front end control means to which a second and separate signal is supplied by said microprocessor means, said front end control means including pulse width modulation means to which said second signal is supplied, said pulse width modulation means being responsive to said second signal to produce an output signal which is supplied as an input to said DC-AC conversion means, whereby said power means controls at least one of the voltage or current supplied by said power means to said motor.

2. The drive system of claim 1 wherein said motor is an AC induction motor.

3. The drive system of claim 2 wherein DC-AC inversion means is a six step inverter.

4. The drive system of claim 2 wherein said AC-DC conversion means is a buck converter.

5. The drive system of claim 2 wherein said AC-DC conversion means is a buck boost converter.

6. The drive system of claim 2 further including as the function selectors a control console on the household appliance accessible to the user.

7. The drive system of claim 6 wherein said control console includes a plurality of switches operable by the user to select those performance functions which the household appliance is to perform.

8. The drive system of claim 7 wherein said microprocessor means has as one set of inputs the user operated switch settings.

9. The drive system of claim 8 wherein said front end controller means further includes buffer means responsive to an input from said microprocessor means to control operation of said pulse width modulator.

10. The drive system of claim 9 wherein said front end controller means further includes harmonic control means interconnected with said pulse width modulator to prevent harmonic distortion in the ac current drawn from said electrical energy source.

11. The drive system of claim 10 wherein said front end controller means further includes driver current control means responsive to an output of said pulse width modulator to provide a current control signal to said AC-DC conversion means.

12. The drive system of claim 1 wherein said DC-AC inversion means includes respective current and voltage sensing means providing input signals to said microprocessor means, said microprocessor means in response thereto, supplying a control signal to said inversion means.