Integrated soft start and safety shutdown

Patent metadata

Field	Value
Publication number	US-10135367-B2
Application number	US-201314107811-A
Country	US
Kind code	B2
Filing date	Dec 16, 2013
Priority date	Dec 16, 2013
Publication date	Nov 20, 2018
Grant date	Nov 20, 2018

Abstract

The subject matter of this specification can be embodied in, among other things, a current control assembly that includes an electrical current flow path having a maximum current flow rate, a first current limiter in the electrical current flow path, the first current limiter comprising circuitry configured to adjustably restrict current flow along the electrical current flow path to a flow rate less than the maximum current flow rate in response to receipt of a first signal at a first input port, and a second current limiter in the electrical current flow path, the second current limiter arranged to interrupt the electrical current flow path in response to receipt of a second signal at a second input port.

First claim

What is claimed is:

1. A current control assembly comprising:
an electrical current flow path having a maximum current flow rate;
a first current limiter in the electrical current flow path, the first current limiter comprising circuitry configured to (i) in response to receipt of a first state of the first signal at a first input port, begin a soft start time period, restrict current flow from the electrical input toward the electrical load along the electrical current flow path to a restricted rate greater than zero current flow and less than the maximum current flow rate for the duration of the soft start time period, and permit current flow along the electrical current flow path from the electrical input toward the electrical load along the electrical current flow path at an unrestricted rate upon expiration of the soft start time, and (ii) stop current flow from the electrical input toward the electrical load along the electrical current flow path in response to a second state of the first signal; and
a second current limiter in the electrical current flow path and in series electrical connection with the first current limiter such that current flows through both current limiters simultaneously, the second current limiter arranged to interrupt current flow from the electrical input toward the electrical load along the electrical current flow path in response to receipt of a second signal at a second input port.

2. The current control assembly of claim 1 , wherein
the restricted rate is a variable restricted flow rate ranging from about zero current flow at the start of the soft start time period to an unrestricted rate at the expiration of the soft start time.

3. The current control assembly of claim 1 , wherein the second signal is the first signal.

4. The current control assembly of claim 1 , wherein at least one of the first current limiter and the second current limiter comprise a current limiting component in the electrical current flow path and is selected from one of a field effect transistor, an insulated gate bipolar transistor, or a relay.

5. The current control assembly of claim 1 , wherein the first current limiter comprises a field effect transistor and the second current limiter comprises a field effect transistor.

6. A motor control system with a soft-start capability, comprising:
an electrical current flow path having a maximum current flow rate;
an electrical input, configured to connect an input voltage to the electrical current flow path;
a voltage storage assembly in the electrical current flow path;
a current control assembly in the electrical current flow path, the current control assembly comprising:
a first current limiter in the electrical current flow path, the first current limiter comprising circuitry configured to (i) in response to receipt of a first state of the first signal at a first input port, begin a soft start time period, restrict current flow from the electrical input toward the voltage storage assembly along the electrical current flow path to a restricted rate greater than zero current flow and less than the maximum current flow rate for the duration of the soft start time period, and permit current flow from the electrical input toward the voltage storage assembly along the electrical current flow path at an unrestricted rate upon expiration of the soft start time, and (ii) stop current flow from the electrical input toward the voltage storage assembly along the electrical current flow path in response to a second state of the first signal; and
a second current limiter in the electrical current flow path and in series electrical connection with the first current limiter such that current flows through both current limiters simultaneously, the second current limiter arranged interrupt current flow from the electrical input toward the voltage storage assembly along the electrical current flow path in to receipt of a second signal at a second input port;

a motor controller arranged to receive electrical power from the voltage storage assembly; and
a motor configured to be controlled by the motor controller.

7. The system of claim 6 , wherein
the restricted rate is a variable restricted flow rate ranging from about zero current flow at the start of the soft start time period to an unrestricted rate at the expiration of the soft start time period.

8. The system of claim 6 , wherein the second signal is the first signal.

9. The system of claim 6 , wherein at least one of the first current limiter and the second current limiter comprise a current limiting component in the electrical current flow path and is selected from one of a field effect transistor, an insulated gate bipolar transistor, or a relay.

10. The system of claim 6 , wherein the first current limiter comprises a field effect transistor and the second current limiter comprises a field effect transistor.

11. A method for soft-starting an electrical current-consuming apparatus, the method comprising:
providing a motor control system comprising:
a current control assembly in an electrical current flow path, the current control assembly comprising:
a first current limiter in the electrical current flow path, the first current limiter comprising circuitry configured to (i) adjustably restrict current flow from an electrical input toward an electrical load along the electrical current flow path between an electrical input and a voltage storage assembly in response to a first state of a first signal and (ii) stop current flow from the electrical input toward the electrical load in the electrical current flow path in response to a second state of the first signal, and a first input port; and
a second current limiter in the electrical current flow path and in series electrical connection with the first current limiter such that current flows through both current limiters simultaneously, the second current limiter arranged to interrupt current flow from the electrical input toward the electrical load in the electrical current flow path, and a second input port;

resisting, by the first current limiter and the second current limiter, current flow from the electrical input toward the electrical load in the electrical current flow path;
receiving the first state of a first signal at the first input port;
receiving a second signal at the second input port;
permitting, by the second current limiter in response to the second signal, current flow in the electrical current flow path;
adjustably restricting, by the first current limiter in response to the first state of the first signal, current flow from the electrical input toward the electrical load along the electrical current flow path to a flow rate less than the maximum current flow rate and greater than zero flow;
interrupting, by the first current limiter in response to receipt of the second state of the first signal at the first input port, current flow along the electrical current flow path;
beginning, in response to receipt of the first state of the first signal at the first input port, a soft start time period;
restricting, for the duration of the soft start time period, current flow from the electrical input toward the electrical load along the electrical current flow path to a restricted rate greater than zero current flow and less than the maximum current flow rate; and,
permitting, upon expiration of the soft start time, current flow from the electrical input toward the electrical load along the electrical current flow path at an unrestricted rate.

12. The method of claim 11 ,
wherein the soft start time period has a start time and an end time, and the method further comprises:
restricting, at the st

Assignees

• Woodward Inc

Inventors

• Ried David L
• Kramer Dustin
• Gotko Dan
• Brunswig Charles M
• Opper Greg

Classifications

• H02P1/00 Primary

  Arrangements for starting electric motors or dynamo-electric converters (starting of synchronous motors with electronic commutators H02P6/20, H02P6/22; starting dynamo-electric motors rotating step by step H02P8/04; vector control H02P21/00) · CPC title

• H02H7/08

  for dynamo-electric motors · CPC title

• H02H9/002

  limiting inrush current on switching on of inductive loads subjected to remanence, e.g. transformers · CPC title

• H02P29/032

  Preventing damage to the motor, e.g. setting individual current limits for different drive conditions · CPC title

• H02H7/122 Primary

  for inverters, i.e. DC/AC converters · CPC title