Multilevel Converter Circuit and Method

• US 20200136523A1
• Filed: 10/22/2019
• Published: 04/30/2020
• Est. Priority Date: 10/24/2018
• Status: Active Grant

• Current Assignee: Solaredge Technologies Incorporated
• Original Assignee: Solaredge Technologies Incorporated
• Inventors: Gazit, Meir, Walsh, Menashe
• Granted Patent: US 10,972,016 B2
• Time in Patent Office: Days
• CPC Class Codes: H02J 3/38 Arrangements for parallely feeding a single network by two or more generators, converters or transformers
• CPC Class Codes: H02M 1/0009 Devices or circuits for detecting current in a converter
• CPC Class Codes: H02M 1/0048 Circuits or arrangements for reducing losses using snubbers H02M1/34
• CPC Class Codes: H02M 1/0054 Transistor switching losses periodically suspending operation of switching converter in low power mode H02M1/0035
• CPC Class Codes: H02M 1/0058 by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826
• CPC Class Codes: H02M 1/007 Plural converter units in cascade push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826
• CPC Class Codes: H02M 1/10 Arrangements incorporating converting means for enabling loads to be operated at will from different kinds of power supplies, e.g. from ac or dc
• CPC Class Codes: H02M 7/483 Converters with outputs that each can have more than two voltages levels
• CPC Class Codes: H02M 7/4833 Capacitor voltage balancing
• CPC Class Codes: H02M 7/49 Combination of the output voltage waveforms of a plurality of converters
• CPC Class Codes: H02M 7/537 using semiconductor devices only, e.g. single switched pulse inverters
• CPC Class Codes: H02M 7/5395 by pulse-width modulation
• CPC Class Codes: H02M 7/64 by combination of static with dynamic converters; by combination of dynamo-electric with other dynamic or static converters
• CPC Class Codes: 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

Abstract

A power conversion system including a first converter configured to convert an input voltage into a plurality of discrete voltages. A second converter configured to convert the plurality of discrete voltages into a plurality of modulated voltages. Each modulated voltage of the plurality of modulated voltages comprises two voltage levels equal, respectively, to two of the discrete voltages of the plurality of discrete voltages. A selection unit configured to alternatively output each modulated voltage of the plurality of modulated voltages across a pair of output terminals.

Claims

1. A system comprising:

a first converter comprising first switching circuitry configured to convert an input voltage into a plurality of discrete voltages;

a second converter comprising second switching circuitry configured to convert the plurality of discrete voltages into a plurality of modulated voltages, wherein each modulated voltage of the plurality of modulated voltages comprises two voltage levels equal, respectively, to two of the discrete voltages of the plurality of discrete voltages; and

a selection circuit configured to alternatively output each modulated voltage of the plurality of modulated voltages across a pair of output terminals.

2. The system of claim 1, further comprising a sensor and configured to sense an electrical parameter,

wherein the selection circuit is further configured to alternatively output the each modulated voltage based on the electrical parameter, and

wherein the electrical parameter is selected from at least one of:

voltage, current, impedance, resistance, phase angle, power factor, harmonic distortion, frequency, or power.

3. The system of claim 1, wherein the selection circuit comprises:

a rotary switch comprising terminals, a pole, and a shaft,

wherein the terminals are connectable to one or more output terminals of the second converter, and

wherein the pole is configured to provide the each modulated voltage of the plurality of modulated voltages based on a velocity of rotation of the shaft.

4. The system of claim 1, wherein the selection circuit comprises:

a plurality of interconnected switches configurable to output at least one of the plurality of modulated voltages that are output by the second converter.

5. The system of claim 1, further comprising a controller configured to, based on an electrical parameter, control the second converter according to a modulation scheme.

6. The system of claim 5, wherein the modulation scheme is at least one of:

pulse width modulation (PWM), frequency modulation, or variable frequency and variable pulse width.

7. The system of claim 1, further comprising:

a filter connected to the pair of output terminals of the selection circuit and configured to filter the each modulated voltage that is output by the selection circuit.

8. The system of claim 1, wherein the first switching circuitry comprises at least one of:

a buck circuit, a boost circuit, a buck/boost circuit, or a buck plus (+) boost circuit.

9. The system of claim 1, wherein the first converter is controlled according to a first modulation scheme based on an electrical parameter,

wherein the second converter is controlled according to a second modulation scheme based on the electrical parameter, and wherein the selection circuit is controlled according to a third modulation scheme based on at least one of the electrical parameter or a reference signal.

10. The system of claim 9, wherein a frequency of at least one of the first modulation scheme or the second modulation scheme is lower than a frequency of the third modulation scheme.

11. The system of claim 9, wherein at least one of the first modulation scheme, the second modulation scheme, or the third modulation scheme is at least one of:

pulse width modulation (PWM), frequency modulation, or variable frequency and variable pulse width modulation.

12. The system of claim 1, wherein the second switching circuitry comprises a two-level inverter configured to output at least one modulated voltage of the plurality of modulated voltages.

13. The system of claim 1, wherein second switching circuitry comprises a multi-level inverter configured to output at least one modulated voltage of the plurality of modulated voltages.

14. A method comprising:

converting, by a first converter, an input voltage into a plurality of discrete voltages;

converting, by a second converter, the plurality of discrete voltages into a plurality of modulated voltages, wherein each modulated voltage of the plurality of modulated voltages comprises two voltage levels equal, respectively, to two of the discrete voltages of the plurality of discrete voltages; and

alternatively outputting, by a selection circuit, each modulated voltage of the plurality of modulated voltages across a pair of output terminals.

15. The method of claim 14, wherein the alternatively outputting the each modulated voltage is based on an electrical parameter sensed by a sensor, and wherein the electrical parameter is selected from at least one of:

voltage, current, impedance, resistance, phase angle, power factor, harmonic distortion, frequency, or power.

16. The method of claim 14, wherein the alternatively outputting the each modulated voltage is based on a reference signal comprising at least one of:

a sine wave, a triangular wave, a square wave, or a sawtooth wave.

17. The method of claim 14, wherein the converting by the first converter is performed according to a first modulation scheme based on an electrical parameter,

wherein the converting by the second converter is performed according to a second modulation scheme based on the electrical parameter, and

wherein the alternatively outputting by the selection circuit is performed according to a third modulation scheme based on at least one of the electrical parameter or a reference signal.

18. The method of claim 17, wherein a frequency of at least one of the first modulation scheme or the second modulation scheme is lower than a frequency of the third modulation scheme.

19. The method of claim 17, wherein at least one of the first modulation scheme, the second modulation scheme, or the third modulation scheme is one of:

pulse width modulation (PWM), frequency modulation, or variable frequency and variable pulse width modulation.

20. The method of claim 14, wherein at least one modulated voltage of the plurality of modulated voltages is generated by the second converter via one of a two-level inverter or a multi-level inverter.