Power conversion systems

Abstract

A bridge configured for use with a power converter is provided herein and comprises a dual maximum power point tracking (MPPT) circuitry configured to support multiple independent maximum power point tracking (MPPT) inputs and located on a DC side of the power converter. The dual maximum power point tracking (MPPT) circuitry comprises an inductor configuration connected to an H-bridge formed from switches on the DC side and one of connected to or integrated into a transformer that connects to an AC side of the power converter. The dual maximum power point tracking (MPPT) circuitry cycles between a first switching cycle pattern and a second switching cycle pattern when a DC bus voltage meets a first predetermined voltage and a second predetermined voltage, respectively.

Description

PATENTAttorney Docket No.: EE435WOPOWER CONVERSION SYSTEMS BACKGROUNDField of the Disclosure

[0001] Embodiments of the present disclosure relate generally to power conversion systems and, for example, to power conversion systems comprising dual Maximum Power Point Tracking (MPPT) input microinverters.Description of the Related Art

[0002] Conventional power converters (microinverter) suitable for use with power conversion systems are known. Some power converters circuit are suitable for a single photovoltaic (PV) (or battery) DC input with a single Maximum Power Point Tracking (MPPT) control (charge control). In certain instances, multiple PV inputs can be accommodated based on one or more design decisions. For example, a single MPPT can be used, but the two PV modules need to be connected in series or parallel. While such configurations are relatively inexpensive, they provide low performance. Alternatively, an active MPPT balance / bias circuit can be added to enable two independent MPPT inputs. While such configurations provide high performance, they are relatively expensive, and the bias circuit can create EMI design challenges.

[0003] Thus, the inventor provides herein improved power conversion systems comprising dual MPPT input microinverters.SUMMARY

[0004] In accordance with at least some embodiments, there is provided a bridge configured for use with a power converter. The bridge comprises a dual maximum power point tracking (MPPT) circuitry configured to support multiple independent maximum power point tracking (MPPT) inputs and located on a DC side of the power converter. The dual maximum power point tracking (MPPT) circuitry comprises an inductor configuration connected to an H-bridge formed from switches on the DC side and one of connected to or integrated into a transformer that connects to an AC side of the power converter. The dual maximum power point tracking (MPPT) circuitry cycles between a first switching cycle pattern and a second1813121_v1PATENTAttorney Docket No.: EE435WOswitching cycle pattern when a DC bus voltage meets a first predetermined voltage and a second predetermined voltage, respectively.

[0005] In accordance with at least some embodiments, there is provided a power conversion system comprising a converter and a bridge configured for use with the converter. The bridge comprises a dual maximum power point tracking (MPPT) circuitry configured to support multiple independent maximum power point tracking (MPPT) inputs and located on a DC side of the power converter. The dual maximum power point tracking (MPPT) circuitry comprises an inductor configuration connected to an H-bridge formed from switches on the DC side and one of connected to or integrated into a transformer that connects to an AC side of the power converter. The dual maximum power point tracking (MPPT) circuitry cycles between a first switching cycle pattern and a second switching cycle pattern when a DC bus voltage meets a first predetermined voltage and a second predetermined voltage, respectively.

[0006] In accordance with at least some embodiments, there is provided a method for controlling a converter. The method comprises determining, based on multiple independent maximum power point tracking (MPPT) inputs received by dual maximum power point tracking (MPPT) circuitry located on a DC side of the power converter, when a DC bus voltage meets at least one of a first predetermined voltage or a second predetermined voltage. The dual maximum power point tracking (MPPT) circuitry comprises an inductor configuration connected to an Id-bridge formed from switches on the DC side and one of connected to or integrated into a transformer that connects to an AC side of the converter. The method comprises cycling between at least one of a first switching cycle pattern or a second switching cycle pattern, respectively.

[0007] Various advantages, aspects, and novel features of the present disclosure may be appreciated from a review of the following detailed description of the present disclosure, along with the accompanying figures in which like reference numerals refer to like parts throughout.1813121_v1PATENTAttorney Docket No.: EE435WOBRIEF DESCRIPTION OF THE DRAWINGS

[0008] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments.

[0009] Figure 1 is a schematic diagram of a power conversion system comprising a switched mode power converter, in accordance with embodiments of the present disclosure;

[0010] Figure 2 is a schematic diagram of a power conversion system comprising a DC port (input) inductors, in accordance with embodiments of the present disclosure;

[0011] Figure 3 illustrates schematic diagrams of power conversion systems configured for use with the power conversion systems of Figures 1 and 2 and comprise a DC port (input side) inductors, in accordance with embodiments of the present disclosure;

[0012] Figure 4 is a schematic diagram of DC bridge switching cycle patterns, in accordance with embodiments of the present disclosure; and

[0013] Figure 5 is a flowchart of a method for controlling a converter, in accordance with embodiments of the present disclosure.DETAILED DESCRIPTION

[0014] Embodiments of the present disclosure are directed to improved power conversion systems comprising dual MPPT input microinverters. For example, a bridge configured for use with a power converter can comprise a dual maximum power point tracking (MPPT) circuitry configured to support multiple independent maximum power point tracking (MPPT) inputs. The dual maximum power point tracking (MPPT) circuitry can be located on a DC side of the power converter. The dual maximum power point tracking (MPPT) circuitry comprises an inductor configuration connected to an H-bridge formed from switches on the DC side and 1813121_v1PATENTAttorney Docket No.: EE435WOone of connected to or integrated into a transformer that connects to an AC side of the power converter. The dual maximum power point tracking (MPPT) circuitry cycles between a first switching cycle pattern and a second switching cycle pattern when a DC bus voltage meets a first predetermined voltage and a second predetermined voltage, respectively. Unlike conventional dual MPPT input microinverters, the dual MPPT input microinverters described herein are relatively inexpensive, high performance, and do not create EMI design challenges.

[0015] The foregoing description of embodiments of the disclosure comprises a number of elements, devices, circuits and / or assemblies that perform various functions as described. These elements, devices, circuits, and / or assemblies are exemplary implementations of means for performing their respectively described functions.

[0016] Figure 1 is a schematic diagram of a power conversion system 100 comprising a converter 102 (e.g., a switched mode power converter) in accordance with embodiments of the present disclosure. This diagram only portrays one variation of the myriad of possible system configurations. The present disclosure can function in a variety of power generation environments and systems.

[0017] The power conversion system 100 comprises multiple DC components 120, such as a PV module (e.g., two PV modules) or a battery, coupled to a DC side of the converter 102 (referred to herein as “converter 102”). In other embodiments the DC component 120 may be any suitable type of DC components, such as another type of renewable energy source (e.g., wind farms, hydroelectric systems, and the like), other types of energy storage components, and the like.

[0018] The converter 102 comprises a capacitor 122 coupled to the DC component 120 as well as across an H-bridge 104 formed from switches S-1, S-2, S-3 and S-4. The switches S-1 and S-2 are coupled in series to form a left leg of the H-bridge 104, and the switches S-3 and S-4 are coupled in series to form a right leg of the H-bridge 104. In at least some embodiments, a dual maximum power point tracking (MPPT) circuitry comprising a pair of inductors 121 connects the multiple DC components 120 to the switches S-1, S-2, S-3 and S-4, as described in greater detail below.1813121_v1PATENTAttorney Docket No.: EE435WO

[0019] The output of the H-bridge 104 is coupled across a series combination of a capacitor Cr and inductor L, which form a resonant tank, and the primary winding of a transformer 108. In other embodiments, the resonant tank may be formed by a different configuration of the capacitor Cr and the inductor Lr (e.g., the capacitor Cr and the inductor L may be coupled in parallel); in some embodiments, Lr may represent a leakage inductance from the transformer 108 rather than a physical inductor.

[0020] A series combination of the secondary winding of the transformer 108 and an inductor L is coupled across a bridge which produces a three-phase AC output, although in other embodiments the bridge may produce one or two phases of AC at its output. The bridge can be a half-bridge, full-bridge, Hex-bridge, etc. formed using switches that are arranged to enable current flow to be alternated. For example, the switches can comprise one or more semiconductor (or vacuum tube) devices, e.g., Field Effect Transistor (FET), Junction FET (JFET), Metal Oxide Semiconductor FET (MOSFET), High Electron Mobility Transistor (HEMT), etc. The switches can be used for AC-DC conversion and / or DC-AC conversion (e.g., switches that are controllable). The bridge can be a Bi-directional bridge (sometimes referred to as a cycloconverter bridge or cycloconverter for short) that uses two unidirectional switches connected in series (back-to-back, which can be referred to as Bidirectional switches) -which can conduct current in either direction (when turned on), can block a voltage of either polarity (when turned off), and can also block a voltage in both polarities (e.g., block polar voltage). For illustrative purposes, the secondary winding of the transformer 108 and the inductor L are assumed coupled across a cycloconverter 110. The cycloconverter 110 comprises three 4Q bidirectional switches Q-1 , Q-2, and Q-3 (which may be collectively referred to as switches Q) respectively in a first leg, a second leg, and a third leg coupled in parallel to one another. In accordance with embodiments of the present disclosure, each of the switches Q-1 , Q-2, and Q-3 is a native four quadrant bi-directional switch comprising one or more of the aforementioned semiconductor (or vacuum tube) devices. Alternatively or additionally, the cycloconverter 110 can comprise three monolithically formed switches (e.g., a Monolithic Bi-Directional Switch (MBDS)) -Gallium-Nitride (GaN) based on a HEMT structure, as described in greater detail 1813121_v1PATENTAttorney Docket No.: EE435WObelow. That is, the MBDS refers to the fact that this Bi-Directional Switch (BDS) can be built in a single semiconductor die. In at least some embodiments, each of the switches Q-1 , Q-2, and Q-3 comprises a pair of Gallium-Nitride (GaN) High Electron Mobility Transistors. In at least some embodiments, each of the switches Q-1, Q-2, and Q-3 comprises a first pair of Gallium-Nitride (GaN) High Electron Mobility Transistors and a second pair of Gallium-Nitride (GaN) High Electron Mobility Transistors connected in series.

[0021] The first cycloconverter leg comprises the 4Q switch Q-1 coupled to a capacitor C1, the second cycloconverter leg comprises the 4Q switch Q-2 coupled to a capacitor C2, and the third cycloconverter leg comprises a 4Q switch Q-3 coupled to a capacitor C3. A first AC output phase line is coupled between the switch Q-1 and the capacitor C1 , a second AC output phase line is coupled between the switch Q-2 and the capacitor C2, and a third AC output phase line is coupled between the switch Q-3 and the capacitor C3. The converter 102 may also include additional circuitry not shown, such as voltage and / or current monitors, for obtaining data for power conversion, data reporting, and the like.

[0022] The converter 102 additionally comprises a controller 106 coupled to the H-bridge switches (S-1, S-2, S-3, and S-4) and the cycloconverter switches (Q-1, Q-2, and Q-3) for operatively controlling the switches to generate the desired output power. In some embodiments, the converter 102 may function as a bi-directional converter.

[0023] The controller 106 comprises a CPU 184 coupled to each of support circuits 183 and a memory 186. The CPU 184 may comprise one or more conventionally available microprocessors or microcontrollers. Additionally or alternatively, the CPU 184 may include one or more application specific integrated circuits (ASICs). The support circuits 183 are well known circuits used to promote functionality of the CPU 184. Such circuits include, but are not limited to, a cache, power supplies, clock circuits, buses, input / output (I / O) circuits, and the like. The controller 106 may be implemented using a general purpose computer that, when executing particular software, becomes a specific purpose computer for performing various embodiments of the present disclosure.1813121_v1PATENTAttorney Docket No.: EE435WO

[0024] The memory 186 is a non-transitory computer readable storage medium such as random access memory, read only memory, removable disk memory, flash memory, and various combinations of these types of memory. The memory 186 is sometimes referred to as main memory and may, in part, be used as cache memory or buffer memory. The memory 186 generally stores the OS 187 (operating system), if necessary, of the controller 106 that can be supported by the CPU capabilities. In some embodiments, the OS 187 may be one of a number of commercially available operating systems such as, but not limited to, LINUX, Real-Time Operating System (RTOS), and the like.

[0025] The memory 186 may store various forms application software (e.g., instructions), such as a conversion control module 189 for controlling power conversion by the converter 102, for example maximum power point tracking (MPPT), switching, performing the methods described herein, and the like. The memory 186 may further store a database 199 for storing various data. The controller 106 further processes inputs and outputs to external communications 194 (i.e., gateway) and a grid interface 188.

[0026] Figure 2 is a schematic diagram of a power conversion system 200 comprising a converter 202 (e.g., a switched mode power converter) in accordance with embodiments of the present disclosure.

[0027] The power conversion system 200 comprises the multiple DC components 120 (e.g., two PV modules) coupled to a DC side of the converter 202. The converter 202 comprises the capacitor 122 coupled to the multiple DC components 120 and the H-bridge 104, and in at least some embodiments the dual maximum power point tracking (MPPT) circuitry comprising a pair of inductors 121 connects the multiple DC components 120 to the switches S-1, S-2, S-3 and S-4, as described above with respect to the converter 102. The output of the H-bridge 104 is coupled across a series combination of the capacitor Cr and the inductor Lr, which form a resonant tank, and the primary winding of the transformer 108, as described above with respect to the converter 102. In other embodiments, the resonant tank may be formed by a different configuration of the capacitor Cr and the inductor Lr (e.g., the capacitor Cr and the inductor L may be coupled in parallel); in some1813121_v1PATENTAttorney Docket No.: EE435WOembodiments, Lr may represent a leakage inductance of the transformer 108 rather than a physical inductor.

[0028] A series combination of the secondary winding of the transformer 108 and the inductor L can be coupled across a bridge as described above with respect to Figure 1. For example, the secondary winding of the transformer 108 and the inductor L can be coupled across a cycloconverter 210 which produces a single-phase AC output. For example, the cycloconverter 210 comprises two bi-directional switches Q-1 and Q-2, (collectively referred to as switches Q) respectively in a first leg and a second leg coupled in parallel to one another. In accordance with embodiments of the present disclosure, each of the switches Q-1 and Q-2 is a native four quadrant bi-directional switch comprising one or more of the aforementioned semiconductor (or vacuum tube) devices. Alternatively or additionally, the cycloconverter 210 can comprise two monolithically formed switches (e.g., a Monolithic Bi-Directional Switch (MBDS)) — Gallium-Nitride (GaN) based on a HEMT structure, as described in greater detail below. In at least some embodiments, each of the switches Q-1 and Q-2 comprises a pair of Gallium-Nitride (GaN) High Electron Mobility Transistors. In at least some embodiments, each of the switches Q-1 and Q-2 comprises a first pair of Gallium-Nitride (GaN) High Electron Mobility Transistors and a second pair of Gallium-Nitride (GaN) High Electron Mobility Transistors connected in series.

[0029] The first cycloconverter leg comprises the 4Q switch Q-1 coupled to the capacitor 01 , and the second cycloconverter leg comprises the 4Q switch Q-2 coupled to the capacitor C2. A first AC output phase line is coupled between the switch Q-1 and the capacitor 01 , and a second AC output phase line is coupled between the switch Q-2 and the capacitor C2. The converter 202 may also include additional circuitry not shown, such as voltage and / or current monitors, for obtaining data for power conversion, data reporting, and the like.

[0030] The converter 202 additionally comprises a controller 206 coupled to the H-bridge switches (S-1 , S-2, S-3, and S-4), and the cycloconverter switches (Q-1 and Q-2) for operatively controlling the switches to generate the desired output power. In some embodiments, the converter 202 may function as a bi-directional converter.

[0031] The controller 206 comprises a CPU 284 coupled to each of support circuits 283 and a memory 286. The CPU 284 may comprise one or more conventionally 1813121_v1PATENTAttorney Docket No.: EE435WOavailable microprocessors or microcontrollers. Additionally or alternatively, the CPU 284 may include one or more application specific integrated circuits (ASICs). The support circuits 283 are well known circuits used to promote functionality of the CPU 284. Such circuits include, but are not limited to, a cache, power supplies, clock circuits, buses, input / output (I / O) circuits, and the like. The controller 206 may be implemented using a general purpose computer that, when executing particular software, becomes a specific purpose computer for performing various embodiments of the present disclosure.

[0032] The memory 286 is a non-transitory computer readable medium such as random access memory, read only memory, removable disk memory, flash memory, and various combinations of these types of memory. The memory 286 is sometimes referred to as main memory and may, in part, be used as cache memory or buffer memory. The memory 286 generally stores the OS 287 (operating system), if necessary, of the controller 206 that can be supported by the CPU capabilities. In some embodiments, the OS 287 may be one of a number of commercially available operating systems such as, but not limited to, LINUX, Real-Time Operating System (RTOS), and the like.

[0033] The memory 286 may store various forms of application software, such as a conversion control module 289 for controlling power conversion by the converter 202, for example maximum power point tracking (MPPT), switching, and the like. The memory 286 may further store a database 299 for storing various data. The controller 206 further processes inputs and outputs to external communications 194 (i.e., gateway) and the grid interface 188.

[0034] As noted above, improved power conversion systems comprising a dual MPPT input microinverters circuitry are described herein. Additionally, the new DC bridge switching cycle patterns add an extra degree of freedom that can be used to implement a dual independent MPPT balance / bias circuit. For example, Figure 3 illustrates schematic diagrams of power conversion systems configured for use, for example, with the power conversion systems of Figures 1 and 2 and comprise DC port (input side) inductors (e.g., the pair of inductors 121), and Figure 4 is a schematic diagram of DC bridge switching cycle patterns, in accordance with embodiments of the present disclosure. For illustrative purposes, the power 1813121_v1PATENTAttorney Docket No.: EE435WOconversion systems are configured for single phase AC output, such as in Figure 2, but the power conversion systems can also be configured for three phase AC output, such as in Figure 1.

[0035] For example, in at least some embodiments, the positive (+) end of a first DC input source 320 connects directly to the positive end (+) of the capacitor 122 and the positive end (+) of the H-bridge. Additionally, the negative end (-) of the first DC input source 320 connects directly to one or more input inductors (e.g., the pair of inductors 121). Similarly, the negative (-) end of a second DC input source 322 connects directly to the negative (-) end of the capacitor 122 and the negative (-) end of the H-bridge. Additionally, the positive (+) end of the second DC input source 322 connects directly to the one or more input inductors (e.g., the pair of inductors 121). Thus, the dual MPPT input microinverters circuitry can be defined as a combination of the one or more input inductors, the capacitor 122, and a control scheme that includes one or more switching cycle pattern, as described in greater detail below.

[0036] For example an H-bridge 300 (e.g., the H-bridge 104 / the H-bridge 204) can be configured, for example, for use with a power converter (e.g., the converter 102 / the converter 202). The H-bridge 300 can comprise the dual MPPT input microinverters circuitry 302 located on a DC side of the power converter. The dual MPPT input microinverters circuitry 302 can comprise one or more inductor configurations connected to the H-bridge 300, which can be formed from switches (S-1 to S-4) on the DC side. In at least some embodiments, the one or more inductor configurations can be one of connected to or integrated into a transformer (e.g., the transformer 108) that connects to an AC side of the power converter. In at least some embodiments, the one or more inductor configurations are connected to the transformer 108 and comprises a first inductor 304 and a second inductor 306 connected to a left leg between a first switch (e.g., S-1) and a second switch (e.g., S-2) of the H-bridge 300, a right leg between a third switch (e.g., S-3) and a fourth switch (e.g., S-4) of the H-bridge 300, and a primary winding of the transformer 108 (see left schematic diagram of Figure 3). In at least some embodiments, the inductor configuration can be connected to the transformer 108 and comprises the first inductor 304 connected to a center tap of a primary winding of the transformer 1813121_v1PATENTAttorney Docket No.: EE435WO(see middle schematic diagram of Figure 3). In such embodiments, the primary winding is connected to a left leg between the first switch and the second switch of the H-bridge 300 and a right leg between a third switch and a fourth switch of the Id-bridge 300. Additionally, in such embodiments, the capacitor Cr and the inductor Lr need not be used.

[0037] In at least some embodiments, the inductor configuration is integrated into a primary winding of the transformer (see right schematic diagram of Figure 3). For example, in at least some embodiments, the inductor configuration can comprise a first inductor and a second inductor connected to a left leg between a first switch and a second switch of the H-bridge 300 and a right leg between a third switch and a fourth switch of the H-bridge 300 (similar to left schematic diagram of Figure 3). Alternatively, in at least some embodiments, the inductor configuration can comprise a first inductor connected to a center tap of the primary winding of the transformer, wherein the primary winding is connected to a left leg between a first switch and a second switch of the H-bridge 300 and a right leg between a third switch and a fourth switch of the H-bridge 300 (similar to middle schematic diagram of Figure 3). In such embodiments, considerable leakage inductance may be required between the two DC side transformer winding, and the capacitor Cr and the inductor Lr need not be used.

[0038] The power converter can use one of two different DC bridge switching cycle patterns. For example, both buck and boost switching cycle patterns are used. For example, when a voltage on the first DC input source 320 is greater than a voltage on the second DC input source 322 (i.e., the lower PV voltage is less than the upper PV voltage), the boost switching cycle pattern is used, and, when a voltage on the first DC input source 320 is less than a voltage on the second DC input source 322 (i.e., the lower PV voltage is greater than the upper PV voltage), the buck switching cycle pattern is used.

[0039] For example, the dual MPPT input microinverters circuitry 302 cycles between a first switching cycle pattern and a second switching cycle pattern based on a voltage of the first DC input source 320 and the second DC input source 322 (e.g., a first predetermined voltage). For example, in at least some embodiments, the first switching cycle pattern can comprise +, L, -, L (see Figure 4). In such 1813121_v1PATENTAttorney Docket No.: EE435WOembodiments, the + is where the first switch and the fourth switch are on and the second switch and third switch are off, the L is where the first switch and the third switch are off and the second switch and fourth switch are on, and the - is where the first switch and the fourth switch are off and the second switch and third switch are on. Additionally, as noted above, in such embodiments, the first switching cycle pattern is operable in an input boost mode.

[0040] In at least some embodiments, the second switching cycle pattern can comprise +, II, -, II. In such embodiments, the + is where the first switch and the fourth switch are on and the second switch and third switch are off, the U is where the first switch and the third switch are on and the second switch and fourth switch are off, and the - is where the first switch and the fourth switch are off and the second switch and third switch are on. Additionally, as noted above, in such embodiments, the second switching cycle pattern is operable in an input buck mode.

[0041] In buck / boost duty-cycle off-state logic (e.g., register transfer level (RTL)), the H-Bridge 300 can either buck or boost the DC input voltage, which can be implemented as integer cycle control, e.g., buck or boost can be used the entire off-state. Additionally, the buck / boost control logic (e.g., RTL Hardware, Analog Input Hardware, and / or Firmware) can be achieved using two loop controls. For example inner current control can be based on input inductor current and an outer 2P-2Z (2 pole -2 zero) voltage control loop that regulates the DC Bus voltage, which requires input inductor current measurement as well as input and DC Bus voltage. In at least some embodiments, the input inductor current can be synthesized, thereby eliminating the need for the analog input. A maximum H-Bridge 300 duty-cycle modulation limit control (e.g., RTL Hardware and Firmware) can be achieved by way of a hand-over from duty-cycle control of the H-bridge 300 to phase-shift control of the AC bridge, which occurs at the modulation limit point. Firmware can be used to dynamically adjust the modulation limit according to the DC input voltage.

[0042] In at least some embodiments, H-Bridge 300 zero-volt-switching (ZVS) commutation time control (e.g., RTL Hardware & Analog Input Hardware) can be achieved using known methods, and maximum power point tracker (MPPT) control (e.g., Firmware) can be achieved via added logic for half-line frequency square-wave1813121_v1PATENTAttorney Docket No.: EE435WOperturbation generator. Burst-mode control (e.g., Firmware) can be achieved using H-Bridge 300 to continuously perform the input buck-boost function.

[0043] Figure 5 is a flowchart of a method 500 for controlling a converter, in accordance with embodiments of the present disclosure. As noted above, during operation of the converter 102 / the converter 202, the voltage between the first DC input source 320 and the second DC input source 322 is continuously monitored via the controlled 06 / controller 206. For example, at 502, the method 500 comprises determining, based on multiple independent maximum power point tracking (MPPT) inputs received by dual maximum power point tracking (MPPT) circuitry, when a voltage of the first DC input source 320 and the second DC input source 322 meets at least one of a first predetermined voltage or a second predetermined voltage. For example, the controller 106 / controller 206 can be configured to detect when the voltage of the first DC input source 320 is greater than or less than the voltage of the second DC input source 322.

[0044] Next, at 504, the method 500 comprises cycling between at least one of a first switching cycle pattern or a second switching cycle pattern, respectively. For example, the controller 106 / controller 206 can be configured to cycle between the first switching cycle pattern and the second switching cycle pattern based on the switching cycle pattern of Figure 4. For example, when the voltage of the first DC input source 320 is greater than the voltage of the second DC input source 322, the controller uses the first switching cycle pattern to boost the input voltage (e.g., the boost mode). Similarly, when the voltage of the first DC input source 320 is less than the voltage of the second DC input source 322, the controller uses the second switching cycle pattern to buck the input voltage (e.g., the buck mode).

[0045] For example, an MPPT algorithm can be configured for use with the first DC input source 320 (e.g., a first PV module) and for the second DC input source 322 (e.g., a second PV module). For example, the MPPT algorithm can be configured to operate the first PV module and the second PV module in a manner that allows for maximum PV energy extraction. For example, the MPPT algorithm can be configured to control a relative buck / boost ratio that will achieve a desired voltage imbalance. For example, if the MPPT algorithm determines that maximum PV energy extraction can be achieved when the first PV module is at a first voltage 1813121_v1PATENTAttorney Docket No.: EE435WO(e.g., 27 V) and the second PV module is ata second voltage (e.g., 31 V), the MPPT algorithm is configured to determine the relative buck / boost ratio to achieve such a desired voltage imbalance. In such instances, the MPPT algorithm is configured to operate the first PV module at a higher proportion in boost mode and operate the second PV module at a higher proportion in buck mode. That is, the buck / boost mode for the first PV module and the second PV module is directly interrelated, e.g., if one is operated in boost mode then the other is operated in buck mode.

[0046] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is defined by the claims that follow.1813121_v1

Claims

PATENTAttorney Docket No.: EE435WOCLAIMS:

1. A bridge configured for use with a power converter, comprising:a dual maximum power point tracking (MPPT) circuitry configured to support multiple independent maximum power point tracking (MPPT) inputs and located on a DC side of the power converter, the dual maximum power point tracking (MPPT) circuitry comprising an inductor configuration connected to an H-bridge formed from switches on the DC side and one of connected to or integrated into a transformer that connects to an AC side of the power converter,wherein the dual maximum power point tracking (MPPT) circuitry cycles between a first switching cycle pattern and a second switching cycle pattern when a DC bus voltage meets a first predetermined voltage and a second predetermined voltage, respectively.

2. The bridge of claim 1, wherein the inductor configuration is connected to the transformer and comprises a first inductor and a second inductor connected to a left leg between a first switch and a second switch of the H-bridge, a right leg between a third switch and a fourth switch of the H-bridge, and a primary winding of the transformer.

3. The bridge of claim 2, wherein the multiple independent maximum power point tracking (MPPT) inputs are provided by a first photovoltaic module and a second photovoltaic module.

4. The bridge as in any of claims 1 to 3, wherein the first switching cycle pattern comprises +, L, -, L, is operable in an input boost mode, and the first predetermined voltage is when a first photovoltaic module voltage is greater than a second photovoltaic module voltage,wherein the + is where the first switch and the fourth switch are on and the second switch and third switch are off,wherein the L is where the first switch and the third switch are off and the second switch and fourth switch are on, and1813121_v1PATENTAttorney Docket No.: EE435WOwherein the - is where the first switch and the fourth switch are off and the second switch and third switch are on.

5. The bridge as in any of claims 1 to 3,, wherein the second switching cycle pattern comprises +, U, U, is operable in an input buck mode, and the first predetermined voltage is when a first photovoltaic module voltage is less than a second photovoltaic module voltage,wherein the + is where the first switch and the fourth switch are on and the second switch and third switch are off,wherein the U is where the first switch and the third switch are on and the second switch and fourth switch are off, andwherein the - is where the first switch and the fourth switch are off and the second switch and third switch are on.

6. The bridge of claim 1, wherein the inductor configuration is connected to the transformer and comprises a first inductor connected to a center tap of a primary winding of the transformer, andwherein the primary winding is connected to a left leg between a first switch and a second switch of the H-bridge and a right leg between a third switch and a fourth switch of the H-bridge.

7. The bridge as in any of claims 1 to 3 or 6, wherein the inductor configuration is integrated into a primary winding of the transformer and comprises at least one of:a first inductor and a second inductor connected to a left leg between a first switch and a second switch of the H-bridge and a right leg between a third switch and a fourth switch of the H-bridge; orthe first inductor connected to a center tap of the primary winding of the transformer, wherein the primary winding is connected to the left leg between the first switch and the second switch of the H-bridge and the right leg between the third switch and the fourth switch of the H-bridge.1813121_v1PATENTAttorney Docket No.: EE435WO8. A power conversion system, comprising:a power converter; anda bridge configured for use with the power converter, comprising:a dual maximum power point tracking (MPPT) circuitry configured to support multiple independent maximum power point tracking (MPPT) inputs and located on a DC side of the power converter, the dual maximum power point tracking (MPPT) circuitry comprising an inductor configuration connected to an H-bridge formed from switches on the DC side and one of connected to or integrated into a transformer that connects to an AC side of the power converter,wherein the dual maximum power point tracking (MPPT) circuitry cycles between a first switching cycle pattern and a second switching cycle pattern when a DC bus voltage meets a first predetermined voltage and a second predetermined voltage, respectively.

9. The power conversion system of claim 8, wherein the inductor configuration is connected to the transformer and comprises a first inductor and a second inductor connected to a left leg between a first switch and a second switch of the H-bridge, a right leg between a third switch and a fourth switch of the H-bridge, and a primary winding of the transformer.

10. The power conversion system of claim 9, wherein the multiple independent maximum power point tracking (MPPT) inputs are provided by a first photovoltaic module and a second photovoltaic module.

11. The power conversion system as in any of claims 8 to 10, wherein the first switching cycle pattern comprises +, L, -, L, is operable in an input boost mode, and the first predetermined voltage is when a first photovoltaic module voltage is greater than a second photovoltaic module voltage,wherein the + is where the first switch and the fourth switch are on and the second switch and third switch are off,1813121_v1PATENTAttorney Docket No.: EE435WOwherein the L is where the first switch and the third switch are off and the second switch and fourth switch are on, andwherein the - is where the first switch and the fourth switch are off and the second switch and third switch are on.

12. The power conversion system of claim as in any of claims 8 to 10, wherein the second switching cycle pattern comprises +, U, -, U, is operable in an input buck mode, and the first predetermined voltage is when a first photovoltaic module voltage is less than a second photovoltaic module voltage,wherein the + is where the first switch and the fourth switch are on and the second switch and third switch are off,wherein the II is where the first switch and the third switch are on and the second switch and fourth switch are off, andwherein the - is where the first switch and the fourth switch are off and the second switch and third switch are on.

13. The power conversion system of claim 8, wherein the inductor configuration is connected to the transformer and comprises a first inductor connected to a center tap of a primary winding of the transformer, andwherein the primary winding is connected to a left leg between a first switch and a second switch of the H-bridge and a right leg between a third switch and a fourth switch of the H-bridge.

14. The power conversion system as in any of claims 8 to 10 or 13, wherein the inductor configuration is integrated into a primary winding of the transformer and comprises at least one of:a first inductor and a second inductor connected to a left leg between a first switch and a second switch of the H-bridge and a right leg between a third switch and a fourth switch of the H-bridge; orthe first inductor connected to a center tap of the primary winding of the transformer, wherein the primary winding is connected to the left leg between the1813121_v1PATENTAttorney Docket No.: EE435WOfirst switch and the second switch of the H-bridge and the right leg between the third switch and the fourth switch of the H-bridge.

15. A method for controlling a converter, the method comprising:determining, based on a multiple independent maximum power point tracking (MPPT) inputs received by a dual maximum power point tracking (MPPT) circuitry located on a DC side of a power converter, when a DC bus voltage meets at least one of a first predetermined voltage or a second predetermined voltage, wherein the dual maximum power point tracking (MPPT) circuitry comprises an inductor configuration connected to an H-bridge formed from switches on the DC side and one of connected to or integrated into a transformer that connects to an AC side of the converter; andcycling between at least one of a first switching cycle pattern or a second switching cycle pattern, respectively.

16. The method of claim 15, wherein the inductor configuration is connected to the transformer and comprises a first inductor and a second inductor connected to a left leg between a first switch and a second switch of the H-bridge, a right leg between a third switch and a fourth switch of the H-bridge, and a primary winding of the transformer.

17. The method of claim 16, wherein the multiple independent maximum power point tracking (MPPT) inputs are provided by a first photovoltaic module and a second photovoltaic module.

18. The method as in any of claims 15 to 17, wherein the first switching cycle pattern comprises +, L, -, L, is operable in an input boost mode, and the first predetermined voltage is when a first photovoltaic module voltage is greater than a second photovoltaic module voltage,wherein the + is where the first switch and the fourth switch are on and the second switch and third switch are off,1813121_v1PATENTAttorney Docket No.: EE435WOwherein the L is where the first switch and the third switch are off and the second switch and fourth switch are on, andwherein the - is where the first switch and the fourth switch are off and the second switch and third switch are on.

19. The method as in any of claims 15 to 17, wherein the second switching cycle pattern comprises +, U, -, U, is operable in an input buck mode, and the first predetermined voltage is when a first photovoltaic module voltage is less than a second photovoltaic module voltage,wherein the + is where the first switch and the fourth switch are on and the second switch and third switch are off,wherein the II is where the first switch and the third switch are on and the second switch and fourth switch are off, andwherein the - is where the first switch and the fourth switch are off and the second switch and third switch are on.

20. The method as in any of claims 15 to 17, wherein the inductor configuration is connected to the transformer and comprises a first inductor connected to a center tap of a primary winding of the transformer, andwherein the primary winding is connected to a left leg between a first switch and a second switch of the H-bridge and a right leg between a third switch and a fourth switch of the H-bridge.1813121_v1

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