# US 2025/0219418 A1 · Grid-forming inverter with improved response speed and control method thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2025/0219418 A1 - Document ID: US20250219418A1 - Status: Published application - Kind: A1 - Application number: 19/006,708 - Filed: 2024-12-31 - Published: 2025-07-03 - Earliest claimed: 2024-01-03 - Assignees: Korea Institute of Energy Research - Applicants: Korea Institute of Energy Research - Inventors: Jae Young PARK; Sea Seung Oh; Suk In Park; Mo Se Kang; Hye Jin Kim - Web page: https://patentgrep.com/patent/US20250219418A1 ## CPC - H02J 3/14: by switching loads on to, or off from, the networks, e.g. progressively balanced loading - H02J 3/381: {Dispersed generators} - H02M 7/5395: by pulse-width modulation - H02J 2101/24: Photovoltaics - H02J 2101/28: Wind energy - 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) ## Abstract A grid-forming inverter comprises: a power stage configured to convert electric power according to on/off controls of switching devices and to output converted electric power to a grid; and a control circuit configured to calculate a first phase control value using an inertia model that integrates a difference between a power command value and an active output power value of the power stage, to calculate a second phase control value through feed-forward control that additionally reflects the power command value in the first phase control value, and to control the switching devices using pulse width modulation (PWM) according to the second phase control value. ## Claims ### Claim 1 A grid-forming inverter comprising: a power stage configured to convert electric power according to on/off controls of switching devices and to output converted electric power to a grid; and a control circuit configured to calculate a first phase control value using an inertia model that integrates a difference between a power command value and an active output power value of the power stage, to calculate a second phase control value through feed-forward control that additionally reflects the power command value in the first phase control value, and to control the switching devices using pulse width modulation (PWM) according to the second phase control value. ### Claim 2 (depends on 1) The grid-forming inverter of claim 1, wherein the control circuit applies a first transfer function to the power command value before performing feed-forward control that additionally reflects the power command value in the first phase control value. ### Claim 3 (depends on 2) The grid-forming inverter of claim 2, wherein a bandwidth of the first transfer function is narrower than a bandwidth of a voltage controller disposed between the second phase control value and an output of a PWM signal. ### Claim 4 (depends on 3) The grid-forming inverter of claim 3, wherein the bandwidth of the first transfer function falls within a certain range of 1/10 of the bandwidth of the voltage controller. ### Claim 5 (depends on 1) The grid-forming inverter of claim 1, wherein the control circuit calculates an angular velocity control value by subtracting the active output power value of the power stage and a damping value from the power command value, dividing a result value by a predetermined inertial value, and integrating a result value; and calculate the first phase control value by multiplying the angular control value by a certain coefficient and integrating a result value. ### Claim 6 (depends on 5) The grid-forming inverter of claim 5, wherein the control circuit calculates the damping value by multiplying a difference between the angular velocity control value and an angular velocity value of a gride voltage by a damping coefficient. ### Claim 7 (depends on 6) The grid-forming inverter of claim 6, wherein the angular velocity value of the grid voltage is measured by a phase lock loop (PLL) circuit. ### Claim 8 (depends on 1) The grid-forming inverter of claim 1, wherein the control circuit calculates the second phase control value by multiplying the power command value by a feed-forward gain and adding up a result value to the first phase control value. ### Claim 9 (depends on 8) The grid-forming inverter of claim 8, wherein the feed-forward gain is determined in response to a reciprocal of the maximum output of the power stage. ### Claim 10 (depends on 8) The grid-forming inverter of claim 8, wherein a value of the maximum output is determined by a value obtained by dividing three times a nominal voltage by a reactance. ### Claim 11 A method for controlling a power stage in which a grid-forming inverter converts power according to on/off controls of switching devices and outputs converted power to a grid, the method comprising operations or steps of: calculating a first phase control value using an inertia model that integrate a difference between a power command value and an active output power value of the power stage and calculating a second phase control value through feed-forward control that additionally reflects the power command value in the first phase control value; and performing pulse width modulation (PWM) control with respect to the switching devices based on the second phase control value. ### Claim 12 (depends on 11) The method of claim 11, wherein, in the operation or step of calculating the second phase control value, a first transfer function is applied to the power command value, and subsequently, the feed-forward control that additionally reflects the power command value in the first phase control value is performed. ### Claim 13 (depends on 12) The method of claim 12, wherein a bandwidth of the first transfer function is narrower than a bandwidth of a voltage controller disposed between the second phase control value and an output of a PWM signal. ### Claim 14 (depends on 11) The method of claim 11, wherein, in the operation or step of calculating the second phase control value, an angular velocity control value is calculated by subtracting the active output power value of the power stage and a damping value from the power command value, dividing a result value by a predetermined inertia value, and integrating a result value; and the first phase control value is calculated by multiplying the angular velocity control value by a certain coefficient and integrating a result value. ### Claim 15 (depends on 11) The method of claim 11, wherein, in the operation or step of calculating the second phase control value, the second phase control value is calculated by multiplying the power command value by a feed-forward gain and adding up a result value to the first phase control value.