# US 11,444,552 B2 · Electric power converting device, and electricity generating system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,444,552 B2 - Document ID: US11444552B2 - Status: Granted - Kind: B2 - Application number: 17/598,629 - Filed: 2020-03-30 - Published: 2022-06-16 - Granted: 2022-09-13 - Earliest claimed: 2019-03-29 - Assignees: Tohoku University - Applicants: Tohoku University - Inventors: Shuji Katoh; Yoshikazu Takahashi; Tetsuo Endoh - Web page: https://patentgrep.com/patent/US11444552B2 ## CPC - H02M 1/0025: {Arrangements for modifying reference values, feedback values or error values in the control loop of a converter} - H02M 7/53871: {with automatic control of output voltage or current} - H02M 1/0022: {the disturbance parameters being input voltage fluctuations} - H02M 1/14: Arrangements for reducing ripples from DC input or output - H02M 7/48: using discharge tubes with control electrode or semiconductor devices with control electrode - H02M 7/537: using semiconductor devices only, e.g. single switched pulse inverters - H02M 7/5387: in a bridge configuration - H02M 7/539: with automatic control of output wave form or frequency (H02M7/5375 - H02M7/5387 take precedence) - H02M 7/5395: by pulse-width modulation - H02M 1/32: Means for protecting converters other than automatic disconnection - 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 present invention provides an electric power conversion device and an electric power generation system which are capable of suppressing ripples in a detected voltage and detection delay. ## Claims ### Claim 1 An electric power conversion device configured to be connected to a power system through interconnection impedance, comprising: a converter of which a switch is switched at a predetermined switching cycle, and which outputs power to the power system through the interconnection impedance; a voltage detector that detects an interconnection point voltage between the electric power conversion device and the power system; and a control device that controls the converter on the basis of a moving average of an output voltage of the voltage detector over a predetermined period in correspondence with the switching cycle, wherein the control device sets an active current command value equal to a result from multiplying the output voltage by a real number. ### Claim 2 (depends on 1) The electric power conversion device according to claim 1, wherein the control device calculates an instantaneous voltage on the basis of the output voltage, and generates a voltage command value of the converter from the instantaneous voltage. ### Claim 3 (depends on 1) An electric power generation system comprising: the electric power conversion device according to claim 1. ### Claim 4 An electric power conversion device configured to be connected to a power system through interconnection impedance, comprising: a converter of which a switch is switched at a predetermined switching cycle, and which outputs power to the power system through the interconnection impedance; a voltage detector that detects an interconnection point voltage between the electric power conversion device and the power system; and a control device that controls the converter on the basis of a moving average of an output voltage of the voltage detector over a predetermined period in correspondence with the switching cycle, wherein the control device sets a current command value equal to a result from multiplying the output voltage by a real number, calculates an instantaneous voltage on the basis of the current command value, and generates a voltage command value of the converter from the instantaneous voltage. ### Claim 5 (depends on 4) An electric power generation system comprising: the electric power conversion device according to claim 4. ### Claim 6 An electric power conversion device configured to be connected to a system functioning as an AC voltage source through interconnection impedance, comprising: a converter that includes a switch that is switched to output pulses of different widths at approximately constant cycles, and outputs a predetermined AC voltage; a voltage detector that detects a system voltage of the system; and a control device that controls the converter, wherein the voltage detector includes a detection unit that detects a voltage value at a predetermined point of the system to which the converter is connected, and a filtering unit that computes a moving-average of an output voltage of the detection unit or calculates an approximate value of a moving average of the output voltage over a period of one cycle or several cycles of constant cycles, and the control device includes a voltage command value generation unit that adds at least one or more of an active power component voltage command value for outputting active power and a reactive power component voltage command value for outputting reactive power to the system voltage to calculate a voltage command value. ### Claim 7 (depends on 6) An electric power generation system comprising: the electric power conversion device according to claim 6. ### Claim 8 An electric power conversion device configured to be connected to a power system through interconnection impedance, comprising: a converter that outputs a predetermined AC voltage; a system voltage detection device that detects a system voltage of the power system; and a control device that controls the converter by pulse width modulation control, wherein the system voltage detection device detects the system voltage by calculating a moving average over a period of one cycle or several cycles of a carrier wave used in the pulse width modulation control with respect to a detected voltage, the control device has a function of calculating a voltage command value of the converter on the basis of the system voltage which is calculated by a moving-average computation, and the control device includes a voltage command value generation unit that adds at least one or more of an active power component voltage command value for outputting active power and a reactive power component voltage command value for outputting reactive power to the system voltage to calculate a voltage command value. ### Claim 9 (depends on 8) The electric power conversion device according to claim 8, wherein the control device sets the system voltage multiplied by a real number as the reactive power component voltage command value, and has a function of calculating the active power component voltage command value with the system voltage set as the current command value. ### Claim 10 (depends on 8) The electric power conversion device according to claim 8, wherein the control device has a function of calculating the active power component voltage command value by time-differentiating the system voltage. ### Claim 11 (depends on 8) The electric power conversion device according to claim 8, wherein a phase of the active power component voltage command value shifts from the system voltage by a quarter period. ### Claim 12 (depends on 8) The electric power conversion device according to claim 8, wherein the control device includes a differential operation unit that calculates the active power component voltage command value by time-differentiating a voltage obtained by dividing the system voltage by an interconnection impedance value. ### Claim 13 (depends on 8) The electric power conversion device according to claim 8, wherein the control device has a function of calculating the reactive power component voltage command value and the active power component voltage command value by time-differentiating the system voltage. ### Claim 14 (depends on 8) The electric power conversion device according to claim 8, wherein the control device includes an active component operation unit that calculates the active power component voltage command value by time-differentiating an active current command effective value calculated on the basis of the system voltage multiplied by a real number. ### Claim 15 (depends on 14) The electric power conversion device according to claim 14, wherein the active component operation unit includes a differential operation unit that differentiates the active current command effective value, and adds a product of the differentiated active current command effective value and an inductance value of the interconnection impedance and a product of the active current command effective value and a resistance value of the interconnection impedance to calculate the active power component voltage command value. ### Claim 16 (depends on 14) The electric power conversion device according to claim 14, wherein the control device includes a voltage compensation value operation unit that calculates a voltage compensation value for compensating the active current command effective value on the basis of the system voltage and a rated phase voltage of the power system. ### Claim 17 (depends on 8) The electric power conversion device according to claim 8, wherein the control device includes a reactive component operation unit that calculates the reactive power component voltage command value by time-differentiating a reactive current command effective value calculated on the basis of the system voltage in which a phase is advanced by 90°, which is calculated by rotating a phase by 90° by using a rotation matrix after three-phase/two-phase conversion, and further performing two-phase/three-phase conversion. ### Claim 18 (depends on 17) The electric power conversion device according to claim 17, wherein the reactive component operation unit includes a differential operation unit that differentiates the reactive current command effective value, and adds a product of the differentiated reactive current command effective value and an inductance value of the interconnection impedance and a product of the reactive current command effective value and a resistance value of the interconnection impedance to calculate the reactive power component voltage command value. ### Claim 19 (depends on 17) The electric power conversion device according to claim 17, wherein the control device includes a voltage compensation value operation unit that calculates a voltage compensation value for compensating the reactive current command effective value on the basis of the system voltage and a rated phase voltage of the power system. ### Claim 20 (depends on 8) The electric power conversion device according to claim 8, wherein a current command value is set equal to a result from multiplying the system voltage by a real number. ### Claim 21 (depends on 8) The electric power conversion device according to claim 8, further comprising: a differential operation unit that calculates a product of a differential value or an inexact differential value of the system voltage multiplied by a real number and an inductance value of the interconnection impedance. ### Claim 22 (depends on 8) The electric power conversion device according to claim 8, further comprising: a differential operation unit that calculates a product of a differential value or an inexact differential value of the system voltage which is multiplied by a real number and in which a phase is advanced by 90° or delayed by 90°, and an inductance value of the interconnection impedance. ### Claim 23 (depends on 8) An electric power generation system comprising: the electric power conversion device according to claim 8. ### Claim 24 An electric power conversion device configured to be connected to a power system through interconnection impedance, comprising: a converter that outputs a predetermined AC voltage; a system voltage detection device that detects a system voltage of the power system; and a control device that controls the converter by pulse width modulation control, wherein the system voltage detection device detects the system voltage by calculating a moving average over a period of one cycle or several cycles of a carrier wave used in the pulse width modulation control with respect to a detected voltage, the control device has a function of calculating a voltage command value of the converter on the basis of the system voltage which is calculated by a moving-average computation, and the control device is a vector control unit that calculates the voltage command value by vector control on the basis of the system voltage. ### Claim 25 (depends on 24) The electric power conversion device according to claim 24, wherein a current command value is set equal to a result from multiplying the system voltage by a real number. ### Claim 26 (depends on 24) The electric power conversion device according to claim 24, further comprising: a differential operation unit that calculates a product of a differential value or an inexact differential value of the system voltage multiplied by a real number and an inductance value of the interconnection impedance. ### Claim 27 (depends on 24) The electric power conversion device according to claim 24, further comprising: a differential operation unit that calculates a product of a differential value or an inexact differential value of the system voltage which is multiplied by a real number and in which a phase is advanced by 90° or delayed by 90°, and an inductance value of the interconnection impedance. ### Claim 28 (depends on 24) An electric power generation system comprising: the electric power conversion device according to claim 24. ### Claim 29 An electric power conversion device configured to be connected to a power system through interconnection impedance, comprising: a converter that outputs a predetermined AC voltage; a system voltage detection device that detects a system voltage of the power system; and a control device that controls the converter by pulse width modulation control, wherein the system voltage detection device detects the system voltage by calculating a moving average over a period of one cycle or several cycles of a carrier wave used in the pulse width modulation control with respect to a detected voltage, the control device has a function of calculating a voltage command value of the converter on the basis of the system voltage which is calculated by a moving-average computation, and the electric power conversion device further comprising: a voltage compensation unit that calculates a peak value of the system voltage, and adds a difference between a rated voltage of the power system and the peak value to the system voltage to compensate a difference between the system voltage and the rated voltage. ### Claim 30 (depends on 29) The electric power conversion device according to claim 29, wherein a current command value is set equal to a result from multiplying the system voltage by a real number. ### Claim 31 (depends on 29) The electric power conversion device according to claim 29, further comprising: a differential operation unit that calculates a product of a differential value or an inexact differential value of the system voltage multiplied by a real number and an inductance value of the interconnection impedance. ### Claim 32 (depends on 29) The electric power conversion device according to claim 29, further comprising: a differential operation unit that calculates a product of a differential value or an inexact differential value of the system voltage which is multiplied by a real number and in which a phase is advanced by 90° or delayed by 90°, and an inductance value of the interconnection impedance. ### Claim 33 (depends on 29) An electric power generation system comprising: the electric power conversion device according to claim 29. ### Claim 34 An electric power conversion device configured to be connected to a system functioning as an AC voltage source through interconnection impedance, comprising: a converter that includes a switch that is switched to output pulses of different widths at approximately constant cycles, and outputs a predetermined AC voltage; a voltage detector that detects a system voltage of the system; and a control device that controls the converter, wherein the voltage detector includes a detection unit that detects a voltage value at a predetermined point of the system to which the converter is connected, and a filtering unit that computes a moving-average of an output voltage of the detection unit or calculates an approximate value of a moving average of the output voltage over a period of one cycle or several cycles of constant cycles, the control device has a function of calculating a voltage command value of the converter on the basis of the system voltage which is calculated by a moving-average computation, and a current command value is set equal to a result from multiplying the system voltage by a real number. ### Claim 35 (depends on 34) An electric power generation system comprising: the electric power conversion device according to claim 34. ### Claim 36 An electric power conversion device configured to be connected to a system functioning as an AC voltage source through interconnection impedance, comprising: a converter that includes a switch that is switched to output pulses of different widths at approximately constant cycles, and outputs a predetermined AC voltage; a voltage detector that detects a system voltage of the system; and a control device that controls the converter, wherein the voltage detector includes a detection unit that detects a voltage value at a predetermined point of the system to which the converter is connected, and a filtering unit that computes a moving-average of an output voltage of the detection unit or calculates an approximate value of a moving average of the output voltage over a period of one cycle or several cycles of constant cycles, and the electric power conversion device further comprising: a differential operation unit that calculates a product of a differential value or an inexact differential value of the system voltage multiplied by a real number and an inductance value of the interconnection impedance. ### Claim 37 (depends on 36) An electric power generation system comprising: the electric power conversion device according to claim 36. ### Claim 38 An electric power conversion device configured to be connected to a system functioning as an AC voltage source through interconnection impedance, comprising: a converter that includes a switch that is switched to output pulses of different widths at approximately constant cycles, and outputs a predetermined AC voltage; a voltage detector that detects a system voltage of the system; and a control device that controls the converter, wherein the voltage detector includes a detection unit that detects a voltage value at a predetermined point of the system to which the converter is connected, and a filtering unit that computes a moving-average of an output voltage of the detection unit or calculates an approximate value of a moving average of the output voltage over a period of one cycle or several cycles of constant cycles, and the electric power conversion device further comprising: a differential operation unit that calculates a product of a differential value or an inexact differential value of the system voltage which is multiplied by a real number and in which a phase is advanced by 90° or delayed by 90°, and an inductance value of the interconnection impedance. ### Claim 39 (depends on 38) An electric power generation system comprising: the electric power conversion device according to claim 38.