Service Line Safety Monitor

• US 20120287542A1
• Filed: 05/14/2012
• Published: 11/15/2012
• Est. Priority Date: 05/12/2011
• Status: Active Grant

• Current Assignee: Control Module, Inc.
• Original Assignee: Control Module, Inc.
• Inventors: Bianco, James S.
• Granted Patent: US 8,587,911 B2
• Time in Patent Office: Days
• US Class Current: 361/86
• CPC Class Codes: B60L 53/14 Conductive energy transfer
• CPC Class Codes: G01R 31/69 of terminals at the end of a cable or a wire harness; of plugs; of sockets, e.g. wall sockets or power sockets in appliances
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles

Abstract

A service line safety monitor which may be configured as a separate module or incorporated into an EVSE is adapted to monitor the connection with the service line to determine whether there is a defect in the connection. The module preferably employs a current transformer to determine a no-load and a load applied to the EVSE. Comparisons are made to determine whether there is a power loss. In the event of a power loss beyond a safe limit, the monitor disconnects the EVSE from the service line. A warning indicator is also employed.

Claims

1. A method for detecting a defective connection to an EVSE comprising:

applying line power to the EVSE;

determining whether the EVSE is drawing a load current;

measuring the line voltage when there is no-load current;

storing the measured no-load line voltage in a memory;

applying a current load to the EVSE;

measuring the EVSE load voltage under a load;

determining a voltage loss differential from the load voltage and the no-load voltage;

deriving a power loss from the voltage loss differential;

determining whether the power loss exceeds a safe limit; and

disconnecting the EVSE load from line voltage if the safe limit is exceeded.

2. The method of claim 1 further comprising displaying a warning signal.

3. The method of claim 1 further comprising employing a current transformer to determine the load current.

4. The method of claim 1 wherein the step of disconnecting the EVSE load from line voltage further comprises employing a relay controlled line contact.

5. The method of claim 1 wherein the step of determining whether the power loss exceeds a safe limit further comprises storing safe limit data in a memory and comparing the power loss to said safe limit data.

6. A service line safety monitor comprising:

a connector for applying line power to an EVSE;

a current transformer for measuring the no-load line voltage when there is no-load current drawn by the EVSE;

a memory for storing the measured no-load line voltage;

means for measuring the EVSE load voltage when the EVSE is drawing a load current;

a microprocessor programmed to determine the differential voltage between the no-load voltage and the load voltage measurements, the power loss due to the voltage differential and whether power loss exceeds a safe limit; and

a line contact which is activatable to disconnect the EVSE from the line voltage if a safe limit has been exceeded.

7. The service line safety monitor of claim 6 wherein said line contact is controlled by a relay.

8. The service line safety monitor of claim 6 wherein said memory further stores safe limit data and said microprocessor accesses said safe limit data to determine whether power loss exceeds a safe limit.

9. The service line safety monitor of claim 6 wherein said monitor is configured as a module interposed between the service line and an EVSE.

10. The service line safety monitor of claim 6 wherein said monitor is integrated with said EVSE.

11. The service line safety monitor of claim 6 further comprising an indicator for displaying a warning signal when the safe limit is exceeded.