Synchronous operation system

• US 5,434,486 A
• Filed: 07/07/1993
• Issued: 07/18/1995
• Est. Priority Date: 06/22/1992
• Status: Expired due to Fees

• Current Assignee: Fuji Electric Company Limited (Fuji Electric Systems Company Limited)
• Original Assignee: Fuji Electric Company Limited (Fuji Electric Systems Company Limited)
• Inventors: Tanaka, Yoshikazu
• Primary Examiner(s): Cabeca, John W.
• Application Number:
  US08/086,709
• Time in Patent Office: 741 Days
• Field of Search: 318/44, 318/625, 318/52, 318/53, 318/59, 318/66, 318/68, 318/69, 318/77, 318/78, 318/85, 318/6, 318/7, 318/49, 318/568.11, 242/186, 242/191, 72/9, 72/17, 307/43, 307/46, 307/44, 364/431.05, 364/565
• US Class Current: 318/69
• CPC Class Codes: H02P 5/56 Speed and position comparison between the motors by electrical means

Abstract

In a synchronous operation system, rotating positions of two rotating elements MSP and SSP driven by induction motors IM₁ and IM₂ are maintained in a predetermined positional relation, what is called, a synchronous control by a position adjuster 7. A gain compensating circuit 10 for adjusting an output of the position adjuster 7 by using a detected speed of one rotation element SSP as a parameter is provided, and the gain compensating circuit 10 adjusts the output of the position adjuster 7. Thus, a slippage of the induction motor is compensated in a speed region where the position variation of the two rotating elements becomes excessively large, or in a high speed region (constant output region) exceeding a basic rotation speed in case the synchronous control is carried out by using an induction motor and an invertor for controlling a primary frequency of the induction motor.

Claims

1. A synchronous operation system for maintaining first and second rotating elements in a predetermined positional relation, comprising,

a first induction motor connected to the first rotating element for rotating the same,

a second induction motor connected to the second rotating element for rotating the same,

a position adjuster connected to the first and second rotating elements and outputting a signal for a difference of the second rotating element with respect to the first rotating element,

speed detecting means connected to at least one of the first and second rotating elements for detecting a speed of said at least one of the first and second rotating elements, and

a gain compensating circuit connected to the position adjuster and the speed detecting means, said gain compensating circuit adjusting the signal outputted from the position adjuster based on the speed detected by the speed detecting means, said adjusted signal being supplied to the second induction motor so that rotational speed of the second induction motor is maintained in the predetermined positional relation relative to the first rotating element.

2. A synchronous operation system according to claim 1, wherein said speed detecting means includes a first speed detecting circuit connected to the first rotating element for detecting a speed of the first rotating element, and a second speed detecting circuit connected to the second rotating element for detecting a speed of the second rotating element, said second speed detecting circuit being connected to the gain compensating circuit for providing a signal of the speed from the second rotating element.

3. A synchronous operation system according to claim 2, further comprising a speed adjusting circuit connected to the first and second speed detecting circuits, said speed adjusting circuit calculating a difference of the speed of the second rotating element relative to the speed of the first rotating element and outputting a signal to adjust the speed of the second rotating element.

4. A synchronous operation system according to claim 3, further comprising a power source connected to said both first and second induction motors for supplying a same power to the first and second induction motors.

5. A synchronous operating system according to claim 1, further comprising inverters connected to the first and second induction motors for controlling rotations of the first and second induction motors.

6. A synchronous operation system according to claim 5, wherein said gain compensating circuit includes data for a speed region where the position variation becomes excessively large and for a speed region where slippage of the second induction motor is increased, and adjusts the signal outputted from the position adjuster based on the data relative to the speed detected by the speed detecting means.