Robust inverter topology

Patent metadata

Field	Value
Publication number	US-10848053-B2
Application number	US-201916503781-A
Country	US
Kind code	B2
Filing date	Jul 5, 2019
Priority date	Jul 13, 2018
Publication date	Nov 24, 2020
Grant date	Nov 24, 2020

Abstract

An inverter system includes an inverter controller and at least one surge protection device. The inverter controller is configured to operate multiple switches to provide an alternating current to an output. The at least one surge protection device is configured to limit a voltage on a direct current link of the inverter. The at least one surge protection device includes a variable resistance component coupled to the direct current link of the inverter, a sensing resistor selectively connected in parallel to the variable resistance component by a switching component, a detection device configured to measure a parameter of the sensing resistor, and a control circuit including failure sensing logic configured to detect a failure in the variable resistance component in response to information from the variable resistance component and information from the detection device for the parameter of the sensing resistor.

First claim

We claim:

1. An inverter comprising:
an inverter controller configured to operate a plurality of switches to provide an alternating current to an output; and
a first surge protection device for limiting a voltage a direct current link of the inverter, a first surge protection device comprising:
first variable resistance component coupled to the direct current link of the inverter;
a first sensing resistor selectively connected in parallel to the variable resistance component by a switching component;
a first detection device configured to measure a parameter of the sensing resistor; and
a control circuit including failure sensing logic configured to detect a failure in the variable resistance component in response to information from the variable resistance component and information from the detection device for the parameter of the sensing resistor,

wherein the variable resistance component is a first variable resistance component, the sensing resistor is a first sensing resistor, the switching component is a first switching component, and the detection device is a first detection device, the inverter further comprising:
a second surge protection device for limiting a voltage on the direct current link of the inverter, a second surge protection device comprising:
a second variable resistance component coupled to the direct current link of the inverter;
a second sensing resistor selectively connected in parallel to the second variable resistance component by a second switching component; and
a second detection device configured to measure a voltage across the second sensing resistor.

2. The inverter of claim 1 , wherein the failure sensing logic analyzes information from the first detection device and the second detection device to determine a conduction voltage for the first variable resistance component and the second variable resistance component.

3. The inverter of claim 1 , further comprising:
a direct current link voltage sensor coupled to the direct current link of the inverter.

4. The inverter of claim 3 , wherein the failure sensing logic is configured to selectively connect a second switching resistor using the second switching component and calculate a conduction voltage for the first variable resistance component as a difference between the voltage across the second sensing resistor and the output of the direct current link voltage sensor.

5. The inverter of claim 4 , wherein the control circuit is configured to compare the conduction voltage for the first variable resistance component to an open circuit threshold and determine an open variable resistance element or open condition when the conduction voltage exceeds the threshold.

6. The inverter of claim 5 , wherein the control circuit is configured to activate a failure indicator when the conduction voltage exceeds the threshold.

7. The inverter of claim 4 , wherein the control circuit is configured to compare the conduction voltage for the first variable resistance component to a shorted range and determine shorted variable resistance element or open condition when the conduction voltage is within the shorted range.

8. The inverter of claim 7 , wherein the control circuit is configured to activate a failure indicator when the conduction voltage is within the shorted range.

9. The inverter of claim 8 , wherein the failure indicator includes a message to a management device.

10. The inverter of claim 3 , further comprising:
a fuse connected to the first variable resistance component, wherein the control circuit is configured to determine the fuse is blown in response to data from the direct current link voltage sensor.

11. The inverter of claim 10 , wherein the control circuit is configured to activate a failure indicator when the fuse is blown.

12. The inverter of claim 1 , wherein the variable resistance component includes a metal oxide varistor (MOV), a gas discharge tube, or a Zener diode.

13. The inverter of claim 1 , wherein the control circuit generates a control signal for operation of a semiconductor component, in parallel with the variable resistance component, in response to an output of a direct current link voltage sensor.

14. A method for limiting a voltage on a direct current link of an inverter with a plurality of surge suppression devices, each including a variable impedance component and a sensing component, the method comprising:
receiving first measurement data from a first voltage detection device configured to measure a voltage across a first sensing component;
receiving second measurement data from a second voltage detection device configured to measure a voltage across a second sensing component;
performing an analysis of the first measurement data for the voltage across the first sensing component and the second measurement data for the voltage across the second sensing component;
determining a conduction voltage for the variable impedance component based on the analysis;
performing a comparison of the conduction voltage and a threshold; and
signaling a failure for the inverter in response to the comparison.

15. A system comprising:
an inverter controller configured to operate a plurality of switches to provide an alternating current to an output; and
a plurality of surge protection devices for limiting a voltage on a direct current link of an inverter, each surge protection device comprising:
a plurality of variable impedance components coupled to the direct current link of the inverter;
a plurality of sensing components selectively connected in parallel to the plurality of variable impedance components;
one or more detection devices configured to measure a parameter of the plurality of sensing components; and
a control circuit including failure sensing logic configured to detect a failure in the one of the plurality of variable impedance components in response to information from the one or more detection devices for the parameter.

16. The system of claim 15 , further comprising:
an indicator configured to provide a user with an indication of the failure.

17. The system of claim 15 , wherein the inverter controller is configured to disconnect the inverter from a power grid in response to the failure.

18. The system of claim 15 , wherein the inverter controller is configured to generate a notification to replace one of the plurality of surge protection devices in response to the failure.

Assignees

• Kohler Co

Inventors

• Frampton Isaac S
• Larson Adam

Classifications

• H02M1/32 Primary

  Means for protecting converters other than automatic disconnection · CPC title

• H02H9/042 Primary

  comprising means to limit the absorbed power or indicate damaged over-voltage protection device · CPC title

• G01R31/52

  Testing for short-circuits, leakage current or ground faults · CPC title

• H02H7/1222

  responsive to abnormalities in the input circuit, e.g. transients in the DC input · CPC title

• H02H1/0007

  concerning the detecting means (in general G01R or other subclasses of G01; reed switches H01H71/2445) · CPC title