Multi-port power converter and associated system and use
The invention relates to a multi-port power converter and a power conversion system that implements the power converter of the invention to connect at least two elements in direct current (DC) with at least one element in alternating current (AC) using a single simultaneous conversion stage. Furthermore, the invention relates to the use of the power conversion system.
1. A multi-port power converter, comprising: an array of power transistors, at least one arrangement of inductors, and three bidirectional ports;
wherein the three bidirectional ports comprise: a first direct current (DC) port configured to connect to a first DC element; a second DC port configured to connect to a second DC element; and an AC port configured to connect to at least one single-phase or polyphase alternating current (AC) element;
wherein:
the first DC port is connected to the AC port using the array of power transistors forming a Full-Bridge topology; and
the second DC port is connected to the first DC port using the array of power transistors and the at least one arrangement of inductors forming an interleaved Half-Bridge Buck-Boost topology;
wherein the power converter further comprises:
a multivariable control subsystem configured to control respective currents in the at least three bidirectional ports through voltage signals to be generated with each branch of the power converter and through on and off signals of each of the power transistors of the array of power transistors, wherein the voltage signals are generated based on instantaneous power requirements in each of the three bidirectional ports; and
wherein each inductor of the at least one arrangement of inductors is connected between one of the phases of the first AC port and the second DC port, wherein each inductor is subjected to a sinusoidal voltage of magnitude and frequency predetermined by the first AC port and the second DC port, depending on the at least one AC element to be connected to the AC port and a voltage to be defined in the second DC port;
wherein the power converter is configured to connect the at least one AC element with the at least two DC elements in a single-stage multiport power converter such that power conversion between the three bidirectional ports occurs simultaneously by operation of the array of power transistors.
2. The multi-port power converter according to claim 1 , wherein each inductor of the at least one arrangement of inductors is a inductively coupled to another inductor of the at least one arrangement of, wherein coupled inductors, when subjected to the sinusoidal voltage, introduces inverse coupling between magnetic fluxes that are generated between the AC port and the second DC port, increasing the impedance associated with the at least one AC element and reducing a circulating electric current generated during the operation of the power converter.
3. The multi-port power converter according to claim 1 , wherein the multivariable control subsystem comprises at least one modulation stage to set a harmonic spectrum of an output voltage of the power converter at predetermined values, wherein the at least one modulation stage receives the voltage signals to be generated with each branch of the power converter and generates the on and off signals of the power transistors.
4. The multi-port power converter according to claim 1 , wherein:
the power converter comprising four transistors and two inductors for use in a single base system;
the power converter comprising six transistors and three inductors for use in a three phase system; or
the power converter is multiplied by N transistors and N inductors for use in in an N-phase polyphase system.
5. The multi-port power converter according to claim 1 , wherein the at least one AC element is one or a combination of the electrical grid, an AC motor, an AC generator, an AC load or an AC source.
6. The multi-port power converter according to claim 1 , wherein the first DC element and/or the second DC element are one or a combination of photovoltaic systems, batteries, capacitors, ultracapacitors, fuel cells, DC microgrids, DC loads or DC sources.
7. The multi-port power converter according to claim 1 , wherein the second DC port is decoupled from the AC port via the at least one arrangement of inductors and therefore allows the connection of a low voltage DC element compared to the first DC port.
8. A multi-port power conversion system, comprising:
a multi-port power converter according to claim 1 ;
the single-phase or polyphase alternating current (AC) element connected to the AC port of the power converter; and
the first DC element is connected to the first DC port of the power converter and wherein the second DC element is connected to the second DC port of the power converter;
wherein the first DC port is connected to the AC port of the power converter through the Full-Bridge topology, and wherein the second DC port of the power converter is connected to the first DC port of the power converter through interleaved Half-Bridge Buck-Boost topology;
wherein the currents in the three bidirectional ports are controlled by the multivariable control subsystem of the power converter through voltage signals to be generated with each branch of the power converter and through on and off signals of each of the power transistors of the power transistor arrangement, wherein the voltage signals are generated based on instantaneous power requirements in each of the at least three bidirectional ports;
wherein each inductor of the at least one arrangement of inductors is connected between the AC port and the second DC port;
wherein each inductor of the at least one arrangement of inductors is subjected to a sinusoidal voltage of magnitude and frequency predetermined by the AC port and the second DC port, and
wherein the power converter connects the AC element with the two DC elements in the single-stage multiport power converter.
9. The multi-port power conversion system according to claim 8 , wherein each inductor of the at least one arrangement of inductors is a coupled to another inductor, wherein an arrangement of coupled inductors when subjected to the sinusoidal voltage, introduces reverse coupling between magnetic fluxes that are generated between the AC port and the second DC port, increasing the impedance associated with the AC element and reducing a circulating electric current that is generated in the power converter during its operation.
10. The multi-port power conversion system according to claim 8 , wherein the multivariable control subsystem comprises a modulation stage to set a harmonic spectrum of an output voltage of the power converter at predetermined values, wherein the modulation stage receives the voltage signals to be generated with each branch of the power converter and generates the on and off signals of the power transistors.
11. The multi-port power conversion system according to claim 8 , wherein:
the power converter comprises four transistors and two inductors for use with a single phase system;
the power converter comprises six transistors and three inductors for use with a three phase system; or
the power converter is multiplied by N transistors and N inductors for use in an N-phase polyphase system.
12. The multi-port power conversion system according to claim 8 , wherein the AC element is selected from one of the electrical grid, an AC motor, an AC generator, an AC load or an AC source.
13. The multi-port conversion system according to claim 8 , wherein the first DC element and/or the second DC element are one or a combination of photovoltaic systems, batteries, capacitors, ultracapacitors, fuel cells, DC micro-grids, DC loads or DC sources.
14. The multi-port power conversion system according to claim 8 , wherein the second DC port is decoupled from the AC port via the at least one arrangement of inductors and therefore allows the connection of a low voltage DC element compared to the first DC port.