# US 12,119,758 B2 · High frequency multi-level inverter

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- Number: US 12,119,758 B2
- Document ID: US12119758B2
- Status: Granted
- Kind: B2
- Application number: 18/350,880
- Filed: 2023-07-12
- Published: 2024-02-15
- Granted: 2024-10-15
- Earliest claimed: 2013-03-14
- Assignees: Solaredge Technologies Ltd.
- Applicants: Solaredge Technologies Ltd.
- Inventors: Ilan Yoscovich
- Web page: https://patentgrep.com/patent/US12119758B2

## CPC

- H02M 7/4837: {Flying capacitor converters}
- H02M 7/42: Conversion of DC power input into AC power output without possibility of reversal
- H02M 7/483: Converters with outputs that each can have more than two voltages levels
- H02M 1/0043: {Converters switched with a phase shift, i.e. interleaved (non-isolated DC/DC converters H02M3/1586)}
- H02M 1/088: for the simultaneous control of series or parallel connected semiconductor devices
- H02M 7/487: Neutral point clamped inverters
- 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)
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS

## Abstract

A multi-level inverter having at least two banks, each bank containing a plurality of low voltage MOSFET transistors. A processor configured to switch the plurality of low voltage MOSFET transistors in each bank to switch at multiple times during each cycle.

## Claims

### Claim 1

A method comprising: switching, at different times and at a switching frequency that is greater than a first frequency, each of a plurality of low voltage MOSFET transistors connected in series in a first bank of an inverter such that a sine-wave alternating current (AC) output signal comprising the first frequency is generated by the inverter.

### Claim 2 (depends on 1)

The method of claim 1, wherein the switching comprises sequentially shifting each of the plurality of low voltage MOSFET transistors connected in series in the first bank by 1/N of a switching period of the switching frequency, and wherein N is a number of the plurality of low voltage MOSFET transistors connected in series in the first bank.

### Claim 3 (depends on 1)

The method of claim 1, wherein the first frequency is 50 Hz or 60 Hz, and wherein the switching frequency is above 16 kHz.

### Claim 4 (depends on 1)

The method of claim 1, wherein each of the plurality of low voltage MOSFET transistors connected in series in the first bank are switched at staggered times based on a duty cycle ratio which changes based on the sine-wave AC output signal.

### Claim 5 (depends on 4)

The method of claim 4, further comprising:
turning on any one of the plurality of low voltage MOSFET transistors connected in series in the first bank, wherein turning on another one of the plurality of low voltage MOSFET transistors is followed after a time delay.

### Claim 6 (depends on 1)

The method of claim 1, wherein the inverter comprises four banks comprising the first bank, a second bank, a third bank, and a fourth bank, each of the second, third, and fourth banks comprising a plurality of low voltage MOSFET transistors, the first bank being connected in series with a second bank, a third bank being connected in series with a fourth bank, and the first and the second bank being in parallel to the third bank and the fourth bank, and
wherein the method further comprises:
controlling each of the plurality of low voltage MOSFET transistors in the first bank at staggered times during each cycle of the switching frequency;
controlling each of the plurality of low voltage MOSFET transistors in the second bank at staggered times during each cycle of the switching frequency;
controlling each of the plurality of low voltage MOSFET transistors in the third bank at staggered times during each cycle of the switching frequency; and
controlling each of the plurality of low voltage MOSFET transistors in the fourth bank at staggered times during each cycle of switching first frequency.

### Claim 7 (depends on 6)

The method of claim 6, wherein the inverter comprises
a first terminal between the first bank and the second bank, a first inductor being connected to the first terminal, and
a second terminal between the third and the fourth bank, a second inductor being connected to the second terminal, and
wherein the method further comprises:
controlling the pluralities of low voltage MOSFET transistors in the first bank, the second bank, the third bank, and in the fourth bank to generate the sine-wave AC output signal between the first inductor and the second inductor.

### Claim 8 (depends on 6)

The method of claim 6, further comprising:
controlling each of the plurality of low voltage MOSFET transistors in the first bank based on a control signal that is:
the same as a control signal provided to a respective transistor of the plurality of low voltage MOSFET transistors in the fourth bank;
an inverted version of a control signal provided to a respective transistor of the plurality of low voltage MOSFET transistors in the second bank; and
an inverted version of a control signal provided to a respective transistor of the plurality of low voltage MOSFET transistors in the third bank.

### Claim 9 (depends on 6)

The method of claim 6, further comprising:
generating a first plurality of control signals, a second plurality of control signals, a third plurality of control signals, and a fourth plurality of control signals, wherein each control signal of the second and third pluralities of control signals is an inverse of a respective one of the first plurality of control signals, and wherein each control signal of the fourth plurality of control signals is the same as a respective one of the first plurality of control signals;
controlling each of the plurality of low voltage MOSFET transistors in the first bank with one of the first plurality of control signals;
controlling each of the plurality of low voltage MOSFET transistors in the second bank with one of the second plurality of control signals;
controlling each of the plurality of low voltage MOSFET transistors in the third bank with one of the third plurality of control signals; and
controlling each of the plurality of low voltage MOSFET transistors in the fourth bank with one of the fourth plurality of control signals.

### Claim 10 (depends on 6)

The method of claim 6, wherein each transistor of the plurality of low voltage MOSFET transistors of each of the first and the second banks is rated for 20, 40, 60, 80, 100, or 120 volts.

### Claim 11 (depends on 1)

The method of claim 1, wherein the switching comprises switching, at different times, each of at least three low voltage MOSFET transistors of the plurality of low voltage MOSFET transistors.

### Claim 12 (depends on 1)

The method of claim 1, wherein the inverter is a single-phase inverter.

### Claim 13

An inverter comprising:
a first bank comprising a plurality of low voltage MOSFET transistors connected in series; and
a controller configured to:
switch, at different times and at a switching frequency that is greater than a first frequency, each of the plurality of low voltage MOSFET transistors connected in series in the first bank such that a sine-wave alternating current (AC) output signal comprising the first frequency is generated by the inverter.

### Claim 14 (depends on 13)

The inverter of claim 13, wherein the first frequency is 50 Hz or 60 Hz, and wherein the switching frequency is above 16 kHz.

### Claim 15 (depends on 13)

The inverter of claim 13, wherein the plurality of low voltage MOSFET transistors connected in series in the first bank comprise at least three low voltage MOSFET transistors.

### Claim 16 (depends on 13)

The inverter of claim 13, wherein the controller is further configured to:
switch each of the plurality of low voltage MOSFET transistors connected in series in the first bank at staggered times based on a duty cycle ratio which changes based on the sine-wave AC output signal.

### Claim 17 (depends on 16)

The inverter of claim 16, wherein the controller is further configured to:
turn on any one of the plurality of low voltage MOSFET transistors connected in series in the first bank, wherein turning on another one of the plurality of low voltage MOSFET transistors in the first bank is followed after a time delay.

### Claim 18 (depends on 13)

The inverter of claim 13, further comprises:
a second bank comprising a plurality of low voltage MOSFET transistors, the first bank being connected in series with the second bank;
a third bank comprising a plurality of low voltage MOSFET transistors;
a fourth bank comprising a plurality of low voltage MOSFET transistors, the third bank being connected in series with the fourth bank, and wherein the first and the second bank are parallel to the third bank and the fourth bank, and wherein the controller is further configured to:
control each of the plurality of low voltage MOSFET transistors of the first bank at staggered times during each cycle of the switching frequency;
control each of the plurality of low voltage MOSFET transistors in the second bank at staggered times during each cycle of the switching frequency;
control each of the plurality of low voltage MOSFET transistors in the third bank at staggered times during each cycle of the switching frequency; and
control each of the plurality of low voltage MOSFET transistors in the fourth bank at staggered times during each cycle of switching first frequency.

### Claim 19 (depends on 18)

The inverter of claim 18, further comprising
a first terminal between the first bank and the second bank, a first inductor being connected to the first terminal, and
a second terminal between the third and the fourth bank, a second inductor being connected to the second terminal,
wherein the controller is further configured to:
control the pluralities of low voltage MOSFET transistors in the first bank, the second bank, the third bank, and in the fourth bank to generate the sine-wave AC output signal between the first inductor and the second inductor.

### Claim 20 (depends on 19)

The inverter of claim 19, wherein each transistor of the plurality of low voltage MOSFET transistors of each of the first and the second banks is rated for 20, 40, 60, 80, 100, or 120 volts.

### Claim 21 (depends on 13)

The inverter of claim 13, wherein N is a number of the plurality of low voltage MOSFET transistors connected in series in the first bank; and wherein each of the plurality of low voltage MOSFET transistors connected in series in the first bank is configured to be sequentially shifted by 1/N of a switching period of the switching frequency.

### Claim 22 (depends on 13)

The inverter of claim 13, wherein the inverter is a single-phase inverter.