# US 2026/0100657 A1 · Non-isolated power conversion apparatus based on virtual isolation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2026/0100657 A1 - Document ID: US20260100657A1 - Status: Published application - Kind: A1 - Application number: 19/210,489 - Filed: 2025-05-16 - Published: 2026-04-09 - Earliest claimed: 2024-10-04 - Assignees: Seoul National University R&Db Foundation - Applicants: Seoul National University R&Db Foundation - Inventors: Jung-Ik HA; Dongsu LEE; Juwon LEE - Web page: https://patentgrep.com/patent/US20260100657A1 ## CPC - H02M 7/25: arranged for operation in series, e.g. for multiplication of voltage - 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 1/123: {Suppression of common mode voltage or current} - H02M 1/32: Means for protecting converters other than automatic disconnection - H02M 1/44: Circuits or arrangements for compensating for electromagnetic interference in converters or inverters - H02M 7/219: in a bridge configuration - H02M 1/126: {using passive filters} - H02M 3/156: with automatic control of output voltage or current, e.g. switching regulators - 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) ## Abstract The non-isolated power conversion apparatus based on virtual isolation includes a filter unit provided with a common mode filtering function and a differential mode filtering function, a non-isolated AC-DC converter configured to convert an AC electrical signal output a first level of DC electrical signal, a non-isolated DC-DC converter configured to convert the first level of DC electrical signal into a second level of DC electrical signal, a grounding unit connected between the non-isolated DC-DC converter and a DC load, a grounding electrical signal measurement device configured to measure a grounding electrical signal or a common mode electrical signal of a system input terminal, and a grounding electrical signal controller configured to compare a grounding electrical signal measurement value with a set grounding electrical signal command and control an output of the non-isolated AC-DC converter and the non-isolated DC-DC converter so that the grounding electrical signal is reduced. ## Claims ### Claim 1 A non-isolated power conversion apparatus based on virtual isolation comprising: a filter unit provided with a common mode filtering function for reducing common mode electromagnetic interference (EMI) noise generated by high frequency components of an AC power system and a differential mode filtering function for reducing ripple components generated due to switching; a non-isolated AC-DC converter configured to convert an AC electrical signal output by the filter unit into a first level of DC electrical signal; a non-isolated DC-DC converter configured to convert the first level of DC electrical signal into a second level of DC electrical signal; a grounding unit connected between the non-isolated DC-DC converter and a DC load; a grounding electrical signal measurement device configured to measure a grounding electrical signal of a grounding wire connecting the grounding unit and a ground terminal or a common mode electrical signal of a system input terminal; and a grounding electrical signal controller configured to compare a grounding electrical signal measurement value received from the grounding electrical signal measurement device with a set grounding electrical signal command and control an output of the non-isolated AC-DC converter and the non-isolated DC-DC converter so that the grounding electrical signal is reduced. ### Claim 2 (depends on 1) The non-isolated power conversion apparatus of claim 1, wherein a neutral point of the filter unit is connected to at least one of a DC link neutral point of the non-isolated AC-DC converter, a DC link neutral point of the non-isolated DC-DC converter, and a neutral point of the grounding unit. ### Claim 3 (depends on 1) The non-isolated power conversion apparatus of claim 1, wherein the non-isolated DC-DC converter is composed of two non-isolated DC-DC converters connected in a series symmetrical or parallel symmetrical manner. ### Claim 4 (depends on 1) The non-isolated power conversion apparatus of claim 1, wherein, when a TT grounding method in which a protective earth (PE) terminal and a system neutral point N are separated is applied to the non-isolated power conversion apparatus based on virtual isolation, the grounding electrical signal measurement device is configured to measure a differential voltage between the system neutral point and the protective earth terminal and transmit the differential voltage to the grounding electrical signal controller, and the grounding electrical signal controller is configured to control the output of the non-isolated AC-DC converter and the non-isolated DC-DC converter so that the differential voltage received from the grounding electrical signal measurement device approximately becomes 0, or control the output of the non-isolated AC-DC converter and the non-isolated DC-DC converter so that the common mode current received from the grounding electrical signal measurement device approximately becomes 0. ### Claim 5 (depends on 1) The non-isolated power conversion apparatus of claim 1, wherein, when a TN-C grounding method in which a protective earth (PE) terminal and a system neutral point N are connected is applied to the non-isolated power conversion apparatus based on virtual isolation, the grounding electrical signal measurement device is configured to measure a ground current flowing through a grounding wire connected to the protective earth terminal and the system neutral point or a common mode current of the system input terminal and transfer the ground current or the common mode current to the grounding electrical signal controller, and the grounding electrical signal controller is configured to control the output of the non-isolated AC-DC converter and the non-isolated DC-DC converter so that the ground current received from the grounding electrical signal measurement device approximately becomes 0.