# US 12,009,690 B2 · Power converters and methods of controlling same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,009,690 B2 - Document ID: US12009690B2 - Status: Granted - Kind: B2 - Application number: 18/344,725 - Filed: 2023-06-29 - Published: 2023-10-26 - Granted: 2024-06-11 - Earliest claimed: 2019-02-25 - Assignees: Nextracker LLC - Applicants: Nextracker LLC - Inventors: Chen Li; Yang Liu; Mohammed Salmaan Khan; Jonathan Kenzo Kamei; Sandeep Sanjiva Lele - Web page: https://patentgrep.com/patent/US12009690B2 ## CPC - H02J 7/35: with light sensitive cells - H02M 3/1582: {Buck-boost converters (H02M3/1584 takes precedence)} - H02P 23/24: Controlling the direction, e.g. clockwise or counterclockwise - H02S 20/32: specially adapted for solar tracking - G05F 1/56: using semiconductor devices in series with the load as final control devices (G05F1/461 takes precedence) - G05F 1/59: including plural semiconductor devices as final control devices for a single load - G05F 1/595: semiconductor devices connected in series - G05F 1/70: Regulating power factor; Regulating reactive current or power - H02M 1/0003: {Details of control, feedback or regulation circuits} - H02M 1/0043: {Converters switched with a phase shift, i.e. interleaved (non-isolated DC/DC converters H02M3/1586)} - 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)} - H02M 1/0074: {Plural converter units whose inputs are connected in series} - H02M 1/0077: {Plural converter units whose outputs are connected in series} - H02M 1/088: for the simultaneous control of series or parallel connected semiconductor devices - H02M 3/01: {Resonant DC/DC converters} - H02M 3/06: using resistors or capacitors, e.g. potential divider - H02M 3/158: including plural semiconductor devices as final control devices for a single load - H02M 3/33571: {Half-bridge at primary side of an isolation transformer} - H02P 27/08: with pulse width modulation - H02S 40/32: comprising DC/AC inverter means associated with the PV module itself, e.g. AC modules - H02S 40/38: Energy storage means, e.g. batteries, structurally associated with PV modules - Y02E 10/56: Power conversion systems, e.g. maximum power point trackers - Y02E 70/30: Systems combining energy storage with energy generation of non-fossil origin - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - 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) - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS - H02S: GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES (obtaining electrical energy from radioactive sources G21H1/12; light sensitive inorganic semiconductor devices H10F; light sensitive organic semiconductor devices H10K30/00; thermoelectric devices H10N10/00; pyroelectric devices H10N15/00) - G05F: SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A power converter converts a medium-voltage output from a solar module to an appropriate voltage to power a solar tracker system. The power converter includes a voltage divider having at least two legs, a first semiconductor switch subassembly coupled in parallel with a first leg of the voltage divider, and a second semiconductor switch subassembly coupled in parallel with a second leg of the voltage divider. The power converter may be a unidirectional or a bidirectional power converter. In implementations, the signals for driving the semiconductor switches of the first and second semiconductor switch subassemblies may be shifted out of phase from each other. In implementations, if the bus voltages to the semiconductor switches are not balanced, the pulse width of the driving signal of the semiconductor switch supplied with the higher bus voltage is decreased for at least one cycle. ## Claims ### Claim 1 A power converter for a photovoltaic (PV) string, the power converter comprising: a voltage divider having at least two legs, the voltage divider configured to be coupled to the photovoltaic (PV) string; a first circuit subassembly including a first semiconductor switch and a third semiconductor switch coupled together in a cascaded configuration, the first circuit subassembly and a first leg of the at least two legs coupled together in parallel; a second circuit subassembly including a second semiconductor switch and a fourth semiconductor switch coupled together in a cascaded configuration, the second circuit subassembly and a second leg of the at least two legs coupled together in parallel; a first inductor having a first end and a second end, the first end coupled between the first semiconductor switch and the third semiconductor switch, the second end of the first inductor coupled to a first output terminal; a second inductor having a first end and a second end, the first end coupled between the second semiconductor switch and the fourth semiconductor switch, the second end of the second inductor coupled to a second output terminal; and a controller configured to: generate a first drive signal for controlling a first voltage supplied to the first and third semiconductor switches; generate a second drive signal for controlling a second voltage supplied to the second and fourth semiconductor switches; and adjust one of the first drive signal or the second drive signal to bring the first voltage and the second voltage closer to each other. ### Claim 2 (depends on 1) The power converter of claim 1, wherein each of the at least two legs of the voltage divider include a resistor and a capacitor coupled together in parallel. ### Claim 3 (depends on 1) The power converter of claim 1, wherein the first drive signal is 180 degrees out of phase from the second pulsed signal. ### Claim 4 (depends on 1) The power converter of claim 1, further comprising a third circuit subassembly including a fifth semiconductor switch and a fifth semiconductor device coupled together, the fifth circuit subassembly and a third leg of the at least two legs coupled together in parallel. ### Claim 5 (depends on 4) The power converter of claim 4, wherein the fifth semiconductor device is a diode or a semiconductor switch. ### Claim 6 (depends on 1) The power converter of claim 1, wherein the first, second, third, and fourth semiconductor switches are metal-oxide-semiconductor field-effect transistors (MOSFETs) or insulated-gate bipolar transistors (IGBTs). ### Claim 7 A method of operating a power converter, the method comprising: synchronizing phases of drive signals applied to respective semiconductor switches coupled in parallel with respective legs of a voltage divider; measuring a solar panel voltage; measuring an output voltage of the power converter; determining the solar panel voltage is greater than twice the output voltage; and shifting a phase of at least one of the drive signals so that the drive signals are out of phase from each other. ### Claim 8 (depends on 7) The method of claim 7, wherein shifting the phases of the at least one of the drive signals includes shifting the phases of at least one of the drive signals so that the drive signals are out of phase from each other by 180 degrees. ### Claim 9 (depends on 7) The method of claim 7, wherein the drive signals are pulse-width modulation (PWM) drive signals. ### Claim 10 A method of operating a power converter, the method comprising: measuring a first voltage supplied to a first semiconductor switch coupled in parallel with a first leg of a voltage divider; measuring a second voltage supplied to a second semiconductor switch coupled in parallel with a second leg of the voltage divider; determining the first voltage is greater than the second voltage; decreasing a duty cycle of a drive signal applied to the second semiconductor switch in a next cycle; determining the second voltage is greater than the first voltage; and decreasing a duty cycle of a drive signal applied to the first semiconductor switch in a next cycle. ### Claim 11 (depends on 10) The method of claim 10, wherein the determining the first voltage is greater than the second voltage includes determining the first voltage is greater than the second voltage plus a predetermined voltage; and wherein the determining the second voltage is greater than the first voltage includes determining the second voltage is greater than the first voltage plus the predetermined voltage. ### Claim 12 (depends on 10) The method of claim 10, wherein decreasing the duty cycle of a drive signal includes decreasing the duty cycle of a drive signal to zero in a next cycle. ### Claim 13 (depends on 10) The method of claim 10, further comprising generating a drive signal applied to the first semiconductor switch and a drive signal applied to the second semiconductor switch so that the drive signals are out of phase from each other. ### Claim 14 (depends on 13) The method of claim 13, wherein the drive signals are 180 degrees out of phase from each other. ### Claim 15 (depends on 10) The method of claim 10, wherein the drive signal is a pulse-width modulation (PWM) drive signal. ### Claim 16 (depends on 10) The method of claim 10, wherein the duty cycle of the drive signal is decreased by a predetermined amount that brings the first voltage and the second voltage closer to each other.