# US 11,114,859 B2 · Power conversion system, photovoltaic optimizer and power tracking method thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,114,859 B2 - Document ID: US11114859B2 - Status: Granted - Kind: B2 - Application number: 16/809,750 - Filed: 2020-03-05 - Published: 2020-09-17 - Granted: 2021-09-07 - Earliest claimed: 2019-03-15 - Assignees: Silergy Semiconductor Technology (Hangzhou) LTD - Applicants: Silergy Semiconductor Technology (Hangzhou) LTD - Inventors: Kaiwei Yao; Zhiyuan Shen - Web page: https://patentgrep.com/patent/US11114859B2 ## CPC - H02J 3/381: {Dispersed generators} - H02M 3/158: including plural semiconductor devices as final control devices for a single load - H02J 2101/25: {involving maximum power point tracking control for photovoltaic sources} - H02M 1/0022: {the disturbance parameters being input voltage fluctuations} - H02M 1/0025: {Arrangements for modifying reference values, feedback values or error values in the control loop of a converter} - Y02E 10/56: Power conversion systems, e.g. maximum power point trackers - 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) - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract An apparatus for photovoltaic power generation can include: an inverter; and at least one photovoltaic optimizer, where input terminals of each photovoltaic optimizer are coupled to output terminals of a photovoltaic panel, and output terminals of each photovoltaic optimizer are coupled in series with each other between input terminals of the inverter; where a maximum power point of the photovoltaic panel is tracked in accordance with an input voltage of the inverter when the photovoltaic optimizer operates in a first mode; and the maximum power point of the photovoltaic panel is tracked in accordance with an output voltage of the photovoltaic panel when the photovoltaic optimizer operates in a second mode. ## Claims ### Claim 1 An apparatus for photovoltaic power generation, the apparatus comprising: a) an inverter; and b) at least one photovoltaic optimizer, wherein input terminals of each photovoltaic optimizer are coupled to output terminals of a photovoltaic panel, and output terminals of each photovoltaic optimizer are coupled in series with each other between input terminals of the inverter; c) wherein the photovoltaic optimizer is configured to adjust an input voltage reference signal according to changes of an input voltage of the inverter, thereby tracking a maximum power point of the photovoltaic panel, when the photovoltaic optimizer operates in a first mode, wherein a duty cycle of the photovoltaic optimizer is 1 during the first mode; and d) wherein the photovoltaic optimizer is configured to adjust the input voltage reference signal according to changes of an output voltage of the photovoltaic panel, thereby tracking the maximum power point of the photovoltaic panel, when the photovoltaic optimizer operates in a second mode, wherein the duty cycle of the photovoltaic optimizer is adjusted and less than 1 during the second mode. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein in the first mode, the inverter is configured to adjust the input voltage thereof, and the photovoltaic optimizer is configured to operate in a through mode to track the input voltage of the inverter. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein in the second mode, the photovoltaic optimizer is configured to operate in a switching mode to track the output voltage of the photovoltaic panel. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein when the output voltage of the photovoltaic optimizer reaches a preset maximum value, the photovoltaic optimizer operates in a third mode to limit an output voltage of the photovoltaic optimizer to the preset maximum voltage, and the maximum power point of the photovoltaic panel is tracked in accordance with output power of the photovoltaic optimizer adjusted by the inverter. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the photovoltaic optimizer is configured to adjust the input voltage reference signal in accordance with a change of an output voltage of the photovoltaic optimizer that is equal to the input voltage of the inverter in the first mode, and to adjust the input voltage reference signal according to a change of an input voltage of the photovoltaic optimizer that is equal to the output voltage of the photovoltaic panel in the second mode. ### Claim 6 (depends on 5) The apparatus of claim 5, wherein in response to an increase in output power of the photovoltaic optimizer in the first mode, the photovoltaic optimizer is configured to obtain the input voltage reference signal in the next cycle, according to the output voltage of the photovoltaic optimizer in the present cycle. ### Claim 7 (depends on 6) The apparatus of claim 6, wherein in response to an increase in the output power of the photovoltaic optimizer in the first mode, the photovoltaic optimizer is configured to adjust the input voltage reference signal of the photovoltaic optimizer in the next cycle to be the output voltage of the photovoltaic optimizer in the present cycle minus a preset step. ### Claim 8 (depends on 6) The apparatus of claim 6, wherein in response to the output power of the photovoltaic optimizer not increasing in the first mode, the photovoltaic optimizer is configured to keep operating in the first mode or switch from the first mode to the second mode. ### Claim 9 (depends on 5) The apparatus of claim 5, wherein the photovoltaic optimizer is configured to decrease the input voltage reference signal when the output power of the photovoltaic optimizer does not increase and the input voltage of the photovoltaic optimizer increases, or when the output power of the photovoltaic optimizer increases and the input voltage of the photovoltaic optimizer decreases in the second mode. ### Claim 10 (depends on 5) The apparatus of claim 5, wherein the photovoltaic optimizer is configured to increase the input voltage reference signal when the output power of the photovoltaic optimizer does not increase and the input voltage of the photovoltaic optimizer decreases, or when the output power of the photovoltaic optimizer increases and the input voltage of the photovoltaic optimizer increases in the second mode. ### Claim 11 (depends on 5) The apparatus of claim 5, wherein the photovoltaic optimizer is configured to obtain the input voltage reference signal in the next cycle according to the output voltage of the photovoltaic optimizer in a present cycle in a third mode. ### Claim 12 (depends on 1) The apparatus of claim 1, wherein the photovoltaic optimizer is configured to adjust the input voltage reference signal according to a relationship between an operation point of the inverter and the maximum power point of the photovoltaic panel in the first mode. ### Claim 13 (depends on 1) The apparatus of claim 1, wherein the photovoltaic optimizer is configured to adjust the input voltage reference signal according to a relationship between an operation point of the photovoltaic optimizer and the maximum power point of the photovoltaic panel in the second mode. ### Claim 14 (depends on 13) The apparatus of claim 13, wherein when the operation point of the photovoltaic optimizer is at the right of the maximum power point, the input voltage reference signal in the next cycle is decreased based on the input voltage reference signal in the present cycle. ### Claim 15 (depends on 13) The apparatus of claim 13, wherein when the operation point of the photovoltaic optimizer is at the left of the maximum power point, the input voltage reference signal in the next cycle is increased based on the input voltage reference signal in the present cycle. ### Claim 16 (depends on 1) The apparatus of claim 1, wherein the photovoltaic optimizer comprises: a) a power converter configured to convert output power of the photovoltaic panel; and b) a control circuit configured to adjust the input voltage reference signal, corresponding to an input voltage of the photovoltaic optimizer, according to the changes of the input voltage of the photovoltaic optimizer, an output voltage of the photovoltaic optimizer, and/or an output current of the photovoltaic optimizer. ### Claim 17 A method of power tracking applied to a photovoltaic power generation system having an inverter and a plurality of photovoltaic optimizers coupled in series between input terminals of the inverter, for each of the plurality of photovoltaic optimizers, the method comprising: a) adjusting an input voltage reference signal corresponding to an input voltage of the photovoltaic optimizer, in accordance with changes of the input voltage, an output voltage, and/or an output current of the photovoltaic optimizer, in order to track a maximum power point of a photovoltaic panel coupled to the photovoltaic optimizer; b) adjusting the input voltage reference signal in accordance with the change of an input voltage of the inverter that is equal to the output voltage of the photovoltaic optimizer in a first mode, thereby tracking a maximum power point of the photovoltaic panel, wherein a duty cycle of the photovoltaic optimizer is 1 during the first mode; and c) adjusting the input voltage reference signal in accordance with the change of the input voltage of the photovoltaic optimizer in a second mode, thereby tracking the maximum power point of the photovoltaic panel, wherein the duty cycle of the photovoltaic optimizer is adjusted and less than 1 during the second mode. ### Claim 18 (depends on 17) The power tracking method of claim 17, further comprising adjusting the input voltage reference signal in the next cycle according to the output voltage of the photovoltaic optimizer in the present cycle, when in a third mode.