# US 2021/0344202 A1 · Device for suppressing potential induced degradation and system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0344202 A1 - Document ID: US20210344202A1 - Status: Published application - Kind: A1 - Application number: 17/374,297 - Filed: 2021-07-13 - Published: 2021-11-04 - Earliest claimed: 2016-05-11 - Assignees: Sungrow Power Supply Co., Ltd. - Applicants: Sungrow Power Supply Co., Ltd. - Inventors: Yanfei YU; Hua NI; Zongjun YANG; Shangfang DAI - Web page: https://patentgrep.com/patent/US20210344202A1 ## CPC - H02J 3/38: Arrangements for feeding a single network from two or more generators or sources in parallel; Arrangements for feeding already energised networks from additional generators or sources in parallel - H01F 38/42: Flyback transformers - H02J 3/381: {Dispersed generators} - H02M 3/005: {using Cuk converters} - H02M 3/24: by static converters - H02M 3/335: using semiconductor devices only - H02M 7/00: Conversion of AC power input into DC power output; Conversion of DC power input into AC power output - H02M 7/06: using discharge tubes without control electrode or semiconductor devices without control electrode - H02M 7/217: using semiconductor devices only - H02J 2101/24: Photovoltaics - 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 - H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES - 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 Provided are a device for suppressing potential induced degradation and a system. The device includes a rectification circuit, a non-isolated voltage conversion circuit and at least one capacitor. An input terminal of the rectification circuit is connected to an output terminal of a converter, the rectification circuit is configured to rectify an alternating current outputted by the converter into a direct current, the non-isolated voltage conversion circuit is configured to perform voltage conversion on the direct current outputted by the rectification circuit, and the voltage conversion is boost conversion or voltage reverse conversion. The capacitor is connected in parallel with an output terminal of the direct current, and either a positive electrode or a negative electrode of the capacitor is grounded. ## Claims ### Claim 1 A device for suppressing potential induced degradation, connected between an alternating current output terminal of a converter and a grid-connected power frequency transformer in a photovoltaic system, comprising: a rectification circuit; a non-isolated voltage conversion circuit; and at least one capacitor, wherein an input terminal of the rectification circuit is connected to an output terminal of the converter, the rectification circuit is configured to rectify an alternating current outputted by the converter into a direct current, the non-isolated voltage conversion circuit is configured to perform voltage conversion on the direct current outputted by the rectification circuit, and the voltage conversion is boost conversion or voltage reverse conversion, or an input terminal of the non-isolated voltage conversion circuit is connected to an output terminal of the converter, the non-isolated voltage conversion circuit is configured to perform voltage conversion on an alternating current outputted by the converter, the voltage conversion is boost conversion, and the rectification circuit is configured to rectify an alternating current outputted by the non-isolated voltage conversion circuit into a direct current; wherein the non-isolated voltage conversion circuit is any one of a Boost circuit, a Buck-boost circuit, a Cuk circuit, a Sepic circuit and a Zeta circuit, in a case that the input terminal of the rectification circuit is connected to the output terminal of the converter; wherein the capacitor is connected in parallel with an output terminal of the direct current, and either a positive electrode or a negative electrode of the capacitor is grounded. ### Claim 2 (canceled) ### Claim 3 (canceled) ### Claim 4 (depends on 1) The device for suppressing potential induced degradation according to claim 1, wherein an output terminal of a Buck-boost circuit is connected in parallel with the capacitor in a case that the non-isolated voltage conversion circuit is the Buck-boost circuit, or an output terminal of a Boost circuit connected in parallel with the capacitor in a case that the non-isolated voltage conversion circuit is the Boost circuit; and an output voltage of the non-isolated voltage conversion circuit is controlled to make a voltage to earth of the photovoltaic system negative, in a case that the positive electrode of the capacitor is grounded, and the output voltage of the non-isolated voltage conversion circuit is controlled to make the voltage to earth of the photovoltaic system positive in a case that the negative electrode of the capacitor is grounded. ### Claim 5 (depends on 4) The device for suppressing potential induced degradation according to claim 4, wherein the rectification circuit is an uncontrolled rectification bridge. ### Claim 6 (canceled) ### Claim 7 (canceled) ### Claim 8 (canceled) ### Claim 9 (canceled) ### Claim 10 (canceled) ### Claim 11 A photovoltaic system, comprising a device for suppressing potential induced degradation, and a photovoltaic (PV) array, a converter and a transformer, wherein the PV array is connected to an input terminal of the converter, an output terminal of the converter is connected to an input terminal of the transformer, and an output terminal of the transformer is connected to a power grid or a load, the device for suppressing potential induced degradation is connected between an alternating current output terminal of a converter and a grid-connected power frequency transformer in a photovoltaic system, and the device for suppressing potential induced degradation includes: a rectification circuit; a non-isolated voltage conversion circuit and at least one capacitor, wherein an input terminal of the rectification module is connected to an output terminal of the converter, the rectification circuit is configured to rectify an alternating current outputted by the converter into a direct current, the non-isolated voltage conversion circuit is configured to perform voltage conversion on the direct current outputted by the rectification circuit, and the voltage conversion is boost conversion or voltage reverse conversion, or an input terminal of the non-isolated voltage conversion circuit is connected to an output terminal of the converter, the non-isolated voltage conversion circuit is configured to perform voltage conversion on an alternating current outputted by the converter, the voltage conversion is boost conversion, and the rectification circuit is configured to rectify an alternating current outputted by the non-isolated voltage conversion circuit into a direct current; wherein the non-isolated voltage conversion circuit is any of a Boost circuit, a Buck-boost circuit, a Cuk circuit, a Sepic circuit and a Zeta circuit, in a case that the input terminal of the rectification circuit is connected to the output terminal of the converter; wherein the capacitor is connected in parallel with an output terminal of the direct current, and either a positive electrode or a negative electrode of the capacitor is grounded. ### Claim 12 (canceled) ### Claim 13 (canceled) ### Claim 14 (depends on 11) The photovoltaic system according to claim 11, wherein an output terminal of a Buck-boost circuit is connected in parallel with the capacitor in a case that the non-isolated voltage conversion circuit is the Buck-boost circuit, or an output terminal of a Boost circuit is connected in parallel with the capacitor in a case that the non-isolated voltage conversion circuit is the Boost circuit; and an output voltage of the non-isolated voltage conversion circuit is controlled to make a voltage to earth of the photovoltaic system negative, in a case that the positive electrode of the capacitor is grounded, and the output voltage of the non-isolated voltage conversion circuit is controlled to make the voltage to earth of the photovoltaic system positive, in a case that the negative electrode of the capacitor is grounded. ### Claim 15 (depends on 14) The photovoltaic system according to claim 14, wherein the rectification is an uncontrolled rectification bridge. ### Claim 16 (canceled) ### Claim 17 (canceled) ### Claim 18 (depends on 11) The photovoltaic system according to claim 11, wherein the number of converters is one or the number of converters is two or more; and in a case that the number of the converters is two or more, an input terminal of each of the converters is connected to one PV array, output terminals of all the converters are connected in parallel, and then the output terminals of all the converters are connected with the input terminal of the transformer.