Device for disconnecting a neutral point of a motor

• US 6,577,086 B2
• Filed: 03/19/2001
• Issued: 06/10/2003
• Est. Priority Date: 03/19/2001
• Status: Expired due to Fees

• Current Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust), Steering Solutions IP Holding Corporation (Nexteer Automotive Group Ltd.)
• Original Assignee: Delphi Technologies, Inc. (Aptiv PLC)
• Inventors: Sebastian, Tomy
• Primary Examiner(s): Leykin, Rita
• Application Number:
  US09/811,935
• Publication Number:
  US 20020130631A1
• Time in Patent Office: 813 Days
• Field of Search: 318/254, 318/138, 318/43, 318/434, 318/439, 388/903
• US Class Current: 318/400.28
• CPC Class Codes: B62D 5/046 Controlling the motor
• CPC Class Codes: H02P 6/34 Modelling or simulation for control purposes
• CPC Class Codes: Y10S 388/903 Protective, e.g. voltage or current limit

Abstract

A circuit for disconnecting a neutral point of an electric machine includes an inductance connected to a lead of the electric machine; a three-terminal solid-state switch that has a first terminal connected to the inductance, a second terminal connected to the neutral point, and a third terminal for controlling a flow of current between the first and second terminals; a controlling circuit coupled to the three-terminal solid-state switch that includes a first loop that has a power source, a resistance, and a voltage regulator to maintain a first voltage upon the third terminal, and a second loop that has a power source, a resistance, and a trigger switch being controllably switched on to thereby close the first loop whereby a second voltage is applied to the three-terminal solid-state switch to thereby substantially electrically disconnect the first terminal from the second terminal.

Claims

1. A circuit for disconnecting a neutral point in an electric machine comprising:

at least one inductance;

at least one three-terminal solid-state switch, the at least one solid-state switch having a first terminal coupled to the at least one inductance, a second terminal coupled to the neutral point; and

a third terminal for controlling a flow of current between the first terminal and the second terminal; and

a controlling circuit coupled to the third terminal of the at least one three-terminal solid-state switch, the controlling circuit comprising;

a first loop having a power source, at least one resistance, and a signal regulator to maintain a first signal at the third terminal of the at least one solid-state switch; and

a second loop having the power source, the at least one resistance, and a trigger switch being controllably switched closed, to maintain a second signal at the third terminal of the at least one solid-state switch to thereby change the state of the at least one three-terminal solid-state switch.

2. The circuit of claim 1 wherein the second loop causes the at least one three-terminal solid-state switch to disconnect the first terminal from the second terminal and thereby disconnect the neutral point from the at least one inductance.

3. The circuit of claim 1 wherein:

the at least one inductance comprises three inductances; and

the at least one three-terminal solid-state switch comprises three three-terminal solid-state switches; and

the controlling circuit is coupled to each of the three three-terminal solid-state switches.

4. The circuit of claim 1 wherein the at least one resistance comprises two resistors.

5. The circuit of claim 4 wherein the two resistors are substantially equal in value.

6. The circuit of claim 1 wherein the signal regulator comprises a Zener diode.

7. The circuit of claim 1 wherein the at least one three-terminal solid-state switch comprises an n-channel metal-oxide semiconductor field effect transistor.

8. The circuit of claim 1 wherein the trigger switch comprises a solid-state switch.

9. The circuit of claim 1 wherein the trigger switch comprises a relay.

10. An Electric Power Steering system comprising:

a motor having a neutral point, coupled to a driving column for assisting steering; and

a circuit for disconnecting the neutral point in the motor, the circuit comprising;

at least one inductance of the motor;

at least one three-terminal solid-state switch, the at least one solid-state switch having a first terminal coupled to the at least one inductance, a second terminal coupled to the neutral point; and

a third terminal for controlling a flow of current between the first terminal and the second terminal; and

a controlling circuit coupled to the third terminal of the at least one three-terminal solid-state switch, the controlling circuit comprising;

a first loop having a power source, at least one resistance, and a voltage regulator to maintain a first voltage upon the third terminal of the at least one solid-state switch; and

a second loop having the power source, the at least one resistance, and a trigger switch being controllably switched closed, thereby closing the second loop such that the first voltage is altered from that of the first loop causing the at least one three-terminal solid-state switch to switch off to electrically disconnect the first terminal from the second terminal and thereby disconnect the neutral point from the at least one inductance.

11. A method for disconnecting a neutral point in an electric machine comprising:

regulating a signal at a control terminal of a solid-state switch to couple the neutral point to the electric machine;

closing a trigger switch to alter the signal at the control terminal of the solid-state switch; and

opening the solid-state switch in accordance with the altered signal at the control terminal to thereby disconnect the neutral point from the electric machine.