# US 10,119,536 B2 · Compressor control apparatus and control method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,119,536 B2 - Document ID: US10119536B2 - Status: Granted - Kind: B2 - Application number: 15/519,919 - Filed: 2015-11-02 - Published: 2017-11-23 - Granted: 2018-11-06 - Earliest claimed: 2014-10-31 - Assignees: LG Electronics Inc. - Applicants: LG Electronics Inc. - Inventors: Jaeyoo Yoo; Sungho Park; Gyunam Kim - Web page: https://patentgrep.com/patent/US10119536B2 ## CPC - F04B 49/06: Control using electricity (regulating by means of floats actuating electric switches F04B49/04) - F04B 35/04: the means being electric - H02M 1/14: Arrangements for reducing ripples from DC input or output - H02M 5/4585: {having a rectifier with controlled elements} - H02P 25/032: Reciprocating, oscillating or vibrating motors - H02P 27/06: using DC to AC converters or inverters (H02P27/05 takes precedence) - F04B 2203/0202: Voltage - F04B: POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS (machines for liquids, or pumps, of rotary-piston or oscillating-piston type F04C; non-positive-displacement pumps F04D; pumping of fluid by direct contact of another fluid or by using inertia of fluid to be pumped F04F) - 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) - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS ## Abstract A compressor control apparatus includes a rectifying unit configured to rectify power applied from the outside, a DC link unit configured to include a pair of capacitors and smooth the rectified voltage, an inverter unit configured to include a pair of switches and convert the smoothed DC voltage into a driving voltage of a motor according to a control signal, and a control unit configured to generate the control signal, wherein the control unit applies a DC offset voltage to the driving voltage according to a direction of a current applied to the motor on the basis of a result obtained by comparing voltages across the pair of capacitors. ## Claims ### Claim 1 A compressor control apparatus, comprising: a rectifying unit configured to rectify power applied from an outside; a DC link unit configured to include a first capacitor and a second capacitor and smooth the rectified voltage; an inverter unit configured to include a first inverter switch and a second inverter switch and convert the smoothed DC voltage into a driving voltage of a motor according to a control signal; and a control unit configured to generate the control signal, wherein the control unit applies a DC offset voltage to the driving voltage according to a direction of a current applied to the motor on the basis of a result obtained by comparing voltages across the first capacitor and the second capacitor, wherein when a voltage across the first capacitor is greater than a voltage across the second capacitor, the control unit applies the driving voltage not including the DC offset voltage in a time section of a direction of a second current flowing from a first node to a second node. ### Claim 2 (depends on 1) The compressor control apparatus of claim 1, wherein when the voltages across the first capacitor and the second capacitor are equal, the driving voltage to which the offset voltage has been applied is symmetrical horizontally in relation to a zero potential. ### Claim 3 (depends on 1) The compressor control apparatus of claim 1, wherein when the voltages across the first capacitor and the second capacitor are different, the driving voltage to which the offset voltage has been applied is asymmetrical horizontally in relation to the zero potential. ### Claim 4 (depends on 3) The compressor control apparatus of claim 3, wherein the motor is connected to the first node between the first capacitor and the second capacitor connected in series and the second node between a first inverter switch and a second inverter switch connected in series, and a first loop is formed by the first capacitor, the first inverter switch, and the motor, and a second loop is formed by the second capacitor, the second inverter switch, and the motor. ### Claim 5 (depends on 1) The compressor control apparatus of claim 1, wherein when a voltage across the second capacitor is greater than a voltage across the first capacitor, the control unit applies the driving voltage not including the DC offset voltage in a time section of a direction of a first current flowing from the second node to the first node. ### Claim 6 (depends on 4) The compressor control apparatus of claim 4, wherein the controller additionally applies the DC offset voltage to the driving voltage until when the voltage across the first capacitor and the voltage across the second capacitor become equal. ### Claim 7 (depends on 1) The compressor control apparatus of claim 1, wherein a magnitude of the DC offset voltage is set on the basis of a difference between the measured voltages across the two capacitors. ### Claim 8 (depends on 1) The compressor control apparatus of claim 1, wherein a magnitude of the DC offset voltage is set on the basis of a difference between a magnitude of a current flowing in the first direction of the motor and a magnitude of a current flowing in a second direction. ### Claim 9 A method for controlling a compressor including a rectifying unit configured to rectify power applied from an outside, a DC link unit configured to include a first capacitor and a second capacitor and smooth the rectified voltage, an inverter unit configured to include a first inverter switch and a second inverter switch and convert the smoothed DC voltage into a driving voltage of a motor according to a control signal, and a control unit configured to generate the control signal, the method comprising: measuring a voltage across each of the first capacitor and the second capacitor; comparing the measured voltages across the two capacitors; and applying a DC offset voltage to the driving voltage according to a direction of a current applied to the motor on the basis of the comparison result, wherein when a voltage across the first capacitor is greater than a voltage across the second capacitor, the driving voltage not including the DC offset voltage is applied in a time section of a direction of a second current flowing from a first node to a second node. ### Claim 10 (depends on 9) The method of claim 9, when the magnitudes of the measured voltages across the first capacitor and the second capacitor are equal, applying a motor voltage symmetrical horizontally in relation to a zero potential to the motor. ### Claim 11 (depends on 9) The method of claim 9, further comprising: when the magnitudes of the measured voltages across the first capacitor and the second capacitor are different, applying a motor voltage asymmetrical horizontally in relation to the zero potential to the motor. ### Claim 12 (depends on 11) The method of claim 11, wherein the motor is connected to the first node between the first capacitor and the second capacitor connected in series and the second node between a first inverter switch and a second inverter switch connected in series, and a first loop is formed by the first capacitor, the first inverter switch, and the motor, and a second loop is formed by the second capacitor, the second inverter switch, and the motor. ### Claim 13 (depends on 12) The method of claim 12, wherein when a voltage across the second capacitor is greater than a voltage across the first capacitor, the driving voltage not including the DC offset voltage is applied in a time section of a direction of a first current flowing from the second node to the first node.