# US 2018/0026548 A1 · System and Method for a Power Inverter with Controllable Clamps

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- Number: US 2018/0026548 A1
- Document ID: US20180026548A1
- Status: Published application
- Kind: A1
- Application number: 15/214,994
- Filed: 2016-07-20
- Published: 2018-01-25
- Earliest claimed: 2016-07-20
- Assignees: Infineon Technologies AG
- Applicants: Infineon Technologies AG
- Inventors: Johannes Georg Laven; Heiko Rettinger; Roman Baburske; Uwe Jansen; Thomas Basler
- Web page: https://patentgrep.com/patent/US20180026548A1

## CPC

- H02M 7/44: by static converters
- H02M 1/32: Means for protecting converters other than automatic disconnection
- H02M 7/487: Neutral point clamped inverters
- H03K 5/08: by limiting; by thresholding; by slicing, i.e. combined limiting and thresholding (H03K5/07 takes precedence; comparing one pulse with another H03K5/22; providing a determined threshold for switching H03K17/30)
- H02M 1/0048: {Circuits or arrangements for reducing losses (using snubbers H02M1/34)}
- Y02B 70/10: Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
- H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P)
- H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M)
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS

## Abstract

A system and method for a power inverter with controllable clamps comprises a first voltage swing path, the first voltage swing path including a first plurality of power transistors, the first voltage swing path producing portions of a positive half-wave of an output signal when active; a second voltage swing path, the second voltage swing path including a second plurality of power transistors, the second voltage swing path producing portions of a negative half-wave of the output signal when active; a first clamping component coupled to the first voltage swing path, the first clamping component forming a freewheeling path for the first voltage swing path, the first clamping component comprising a control terminal, the first clamping component having a first stored charge when the control terminal is in a first state and a second stored charge when the control terminal is in a second state, the first stored charge being greater than the second stored charge; and a second clamping component coupled to the second voltage swing path, the second clamping component forming a freewheeling path for the second voltage swing path, the second clamping component comprising a control terminal, the second clamping component having the first stored charge when the control terminal is in the first state and the second stored charge when the control terminal is in the second state.

## Claims

### Claim 1

A device comprising:
a first voltage swing path, the first voltage swing path including a first plurality of power transistors, the first voltage swing path producing portions of a positive half-wave of an output signal when active;
a second voltage swing path, the second voltage swing path including a second plurality of power transistors, the second voltage swing path producing portions of a negative half-wave of the output signal when active;
a first clamping component coupled to the first voltage swing path, the first clamping component forming a freewheeling path for the first voltage swing path, the first clamping component comprising a control terminal, the first clamping component having a first stored charge when the control terminal is in a first state, the first clamping component having a second stored charge when the control terminal is in a second state, the first clamping component having a third stored charge when the control terminal is in a third state, the first stored charge being greater than the second stored charge, the third stored charge being less than the second stored charge; and
a second clamping component coupled to the second voltage swing path, the second clamping component forming a freewheeling path for the second voltage swing path, the second clamping component comprising a control terminal, the second clamping component having the first stored charge when the control terminal is in the first state, the second clamping component having the second stored charge when the control terminal is in the second state, the second clamping component having the third stored charge when the control terminal is in the third state.

### Claim 2 (depends on 1)

The device of claim 1, wherein:
the first voltage swing path comprises a first plurality of power switches coupled to a positive voltage source and a common terminal, the common terminal outputting the output signal;
the first clamping component comprises an anode and a cathode, the anode of the first clamping component coupled to an input signal, the cathode of the first clamping component coupled to the first plurality of power switches;
the second voltage swing path comprises a second plurality of power switches coupled to a negative voltage source and the common terminal; and
the second clamping component comprises an anode and a cathode, the cathode of the second clamping component coupled to the input signal, the anode of the second clamping component coupled to the second plurality of power switches.

### Claim 3 (depends on 2)

The device of claim 2, wherein the first clamping component and the second clamping component are diodes that have a low anode efficiency when the control terminals are in the first state and have a high anode efficiency when the control terminals are in the second state.

### Claim 4 (depends on 3)

The device of claim 3, wherein the diodes include a buried n-doped layer throughout the diodes in a lateral direction between the anode and the cathode.

### Claim 5 (depends on 3)

The device of claim 3, wherein the diodes are metal-oxide-semiconductor (MOS) gated diodes.

### Claim 6 (depends on 1)

The device of claim 1, wherein the first clamping component and the second clamping component are reverse conducting insulated-gate bipolar transistors with diode control (RCDC IGBTs).

### Claim 7

(canceled)

### Claim 8 (depends on 1)

The device of claim 1, wherein the first clamping component and the second clamping component are coupled to a controller, the controller configured to:
measure the output signal; and
switch the control terminals of the first clamping component and the second clamping component to the first state in response to the output signal falling below a predetermined threshold.

### Claim 9 (depends on 8)

The device of claim 8, wherein the controller is further configured to:
switch the control terminals of the first clamping component and the second clamping component to the second state in response to the output signal rising above the predetermined threshold.

### Claim 10 (depends on 8)

The device of claim 8, wherein the controller is further configured to:
switch the control terminal of the first clamping component to the third state;
switch the control terminal of the first clamping component to the second state after a time period elapses; and
activate the first voltage swing path.

### Claim 11

A system comprising:
a neutral point clamped (NPC) inverter comprising a plurality of clamping devices, each of the plurality of clamping devices having a control terminal, each of the plurality of clamping devices having a first stored charge when the control terminal is in a first state and a second stored charge when the control terminal is in a second state, the first stored charge being greater than the second stored charge, the NPC inverter producing an AC output signal from a DC input signal;
a detector configured to measure the AC output signal of the NPC inverter; and
a controller coupled to the detector and the NPC inverter, the controller configured to switch the control terminal of each of the plurality of clamping devices to the first state when the AC output signal measured by the detector falls below a predetermined threshold.

### Claim 12 (depends on 11)

The system of claim 11, wherein the plurality of clamping devices comprise insulated-gate bipolar transistors (IGBTs) in parallel with controllable diodes, the IGBTs and controllable diodes being in voltage swing paths of the NPC inverter.

### Claim 13 (depends on 11)

The system of claim 11, wherein the plurality of clamping devices are diodes that have a low anode efficiency in the first state and a high anode efficiency in the second state.

### Claim 14 (depends on 13)

The system of claim 13, wherein the diodes include a controllable active semiconductor area, and wherein the size of the controllable active semiconductor area in the first state is greater than the size of the controllable active semiconductor area in the second state.

### Claim 15 (depends on 13)

The system of claim 13, wherein the diodes include buried n-doped layers throughout the diodes in a lateral direction between anodes and cathodes of the diodes.

### Claim 16 (depends on 13)

The system of claim 13, wherein the diodes are MOS gated diodes.

### Claim 17 (depends on 11)

The system of claim 11, wherein the plurality of clamping devices are reverse conducting insulated-gate bipolar transistors with diode control (RCDC IGBTs).

### Claim 18 (depends on 11)

The system of claim 11, wherein the controller is further configured to:
switch the control terminal of each of the plurality of clamping devices to the second state when the AC output signal measured by the detector rises above a predetermined threshold.

### Claim 19 (depends on 11)

The system of claim 11, wherein each of the plurality of clamping devices have a third stored charge when the control terminal is in a third state, the third stored charge being less than the second stored charge.

### Claim 20 (depends on 19)

The system of claim 19, wherein the controller is further configured to:
switch the control terminal of a first clamping device of the plurality of clamping devices to the third state;
switch the control terminal of the first clamping device to the second state after a time period elapses; and
activate a path of the NPC inverter coupled to an anode and a cathode of the first clamping device.

### Claim 21 (depends on 20)

The system of claim 20, wherein the path of the NPC inverter is activated between 100 ns and 2 μs after the control terminal of the first clamping device is switched to the second state.

### Claim 22 (depends on 20)

The system of claim 20, wherein the time period is between 1 ms and 10 ms, and a blocking voltage of the clamping devices is less than 2000 V.

### Claim 23 (depends on 20)

The system of claim 20, wherein the time period is between 20 ms and 100 ms, and a blocking voltage of the clamping devices is 6.5 kV.

### Claim 24 (depends on 11)

The system of claim 11, wherein the DC input signal is sourced from a solar panel.

### Claim 25 (depends on 11)

The system of claim 11, wherein the DC input signal is sourced from a wind turbine.

### Claim 26 (depends on 11)

The system of claim 11, wherein the AC output signal is transmitted to an electricity grid.

### Claim 27

A method comprising:
configuring a clamping device in an inverter to operate in a first mode, the inverter producing an output signal equal to a first voltage in the first mode;
switching the clamping device to a second mode;
waiting a time period;
switching the clamping device back to the first mode;
after switching the clamping device back to the first mode, enabling a branch of the inverter coupled to the clamping device;
measuring the output signal; and
switching the clamping device to operate in a third mode in response to the measured output signal being a second voltage less than the first voltage.

### Claim 28

(canceled)