# US 8,342,812 B2 · Variable speed air compressing system having AC and DC power sources > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,342,812 B2 - Document ID: US8342812B2 - Status: Granted - Kind: B2 - Application number: 12/591,902 - Filed: 2009-12-03 - Published: 2010-06-10 - Granted: 2013-01-01 - Earliest claimed: 2008-12-04 - Assignees: Crosspoint Solutions, Inc. - Inventors: Gerald Allen Alston - Web page: https://patentgrep.com/patent/US8342812B2 ## CPC - F04B 49/06: Control using electricity (regulating by means of floats actuating electric switches F04B49/04) - F04B 35/04: the means being electric - 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) ## Abstract A variable speed air compressing system includes a compressor, a motor configured to actuate the compressor, and a rectifier configured to receive alternating current from a first power source and to provide rectified direct current having a first voltage. The system also includes an inverter configured to receive the rectified direct current and to receive direct current from a second power source having a second voltage. The inverter is configured to provide alternating current to the motor. The alternating current provided to the motor is based on the rectified direct current if the first voltage is greater than the second voltage and the alternating current is based on the direct current from the second power source if the second voltage is greater than the first voltage. ## Claims ### Claim 1 A variable speed air compressing system, comprising: a compressor; a motor configured to actuate the compressor; a rectifier configured to receive alternating current from a first power source and to provide rectified direct current having a first voltage; an inverter configured to receive the rectified direct current and to receive direct current from a second power source having a second voltage, the inverter further configured to provide alternating current to the motor, wherein the alternating current provided to the motor is based on the rectified direct current if the first voltage is greater than the second voltage and wherein the alternating current provided to the motor is based on the direct current from the second power source if the second voltage is greater than the first voltage; and a controller configured to vary the first voltage to adjust an amount of allowable sag of the second voltage by raising the first voltage to decrease the amount of allowable sag or by lowering the first voltage to increase the amount of allowable sag. ### Claim 2 (depends on 1) The system of claim 1, wherein the inverter is further configured to provide alternating current to the motor based on both of the rectified direct current and the direct current from the second power source if the first and second voltages are equal. ### Claim 3 (depends on 1) The system of claim 1, wherein the controller is configured to monitor the first and second voltages. ### Claim 4 (depends on 1) The system of claim 1, further comprising: a first voltage sensor configured to read the first voltage; and a second voltage sensor configured to read the second voltage, wherein the controller is configured to monitor the first and second voltages based on the voltage readings of the first and second voltage sensors. ### Claim 5 (depends on 3) The system of claim 3, wherein the compressor is an air compressor configured to selectably drive a plurality of loads. ### Claim 6 (depends on 3) The system of claim 3, wherein the controller further comprises an input device configured to receive user input to raise or lower the first voltage. ### Claim 7 (depends on 3) The system of claim 3, wherein the controller further comprises a display configured to output numeric values of the first and second voltages. ### Claim 8 A variable speed drive for an air compressing system, comprising: a rectifier configured to receive alternating current from a first power source and to provide rectified direct current having a first voltage; an inverter configured to receive the rectified direct current and to receive direct current from a second power source having a second voltage, the inverter further configured to provide alternating current to a motor, wherein the alternating current provided to the motor is based on the rectified direct current if the first voltage is greater than the second voltage and wherein the alternating current provided to the motor is based on the direct current from the second power source if the second voltage is greater than the first voltage; and a controller configured to raise the first voltage to increase the voltage at which the system will transition between the second power source and the first power source and to lower the first voltage to decrease the voltage at which the system will transition between the second power source and the first power source. ### Claim 9 (depends on 8) The variable speed drive of claim 8, wherein the inverter is further configured to provide alternating current to the motor based on both of the rectified direct current and the direct current from the second power source if the first and second voltages are equal. ### Claim 10 (depends on 8) The variable speed drive of claim 8, wherein the controller is configured to monitor the first and second voltages. ### Claim 11 (depends on 8) The variable speed drive of claim 8, further comprising: a first voltage sensor configured to read the first voltage; and a second voltage sensor configured to read the second voltage, wherein the controller is configured to monitor the first and second voltages based on the voltage readings of the first and second voltage sensors. ### Claim 12 (depends on 10) The variable speed drive of claim 10 wherein the compressor is an air compressor. ### Claim 13 (depends on 8) The variable speed drive of claim 8, wherein the controller further comprises an input device configured to receive user input to raise or lower the first voltage. ### Claim 14 (depends on 8) The variable speed drive of claim 8, wherein the controller further comprises a display configured to output numeric values of the first and second voltages. ### Claim 15 A variable speed air compressing system, comprising: a compressor; a motor configured to actuate the compressor; a rectifier configured to receive alternating current from a first power source and to provide rectified direct current having a first voltage; a second power source; an inverter configured to receive the rectified direct current and to receive direct current from a second power source having a second voltage, the inverter further configured to provide alternating current to the motor, wherein the alternating current provided to the motor is based on the rectified direct current if the first voltage is greater than the second voltage and wherein the alternating current provided to the motor is based on the direct current from the second power source if the second voltage is greater than the first voltage; and a controller configured to control an amount of allowable sag of the second voltage by raising or lowering the first voltage effective to change the point at which power to the motor is switched from the second power source to a combination of the first power source and the second power source. ### Claim 16 (depends on 15) The system of claim 15, wherein the inverter is further configured to provide alternating current to the motor based on both of the rectified direct current and the direct current from the second power source if the first and second voltages are equal. ### Claim 17 (depends on 15) The system of claim 15, further comprising: a first voltage sensor configured to read the first voltage; and a second voltage sensor configured to read the second voltage, wherein the controller is configured to monitor the first and second voltages based on the voltage readings of the first and second voltage sensors. ### Claim 18 (depends on 15) The system of claim 15, wherein the second power source is connected to a DC input bus of the inverter. ### Claim 19 (depends on 15) The system of claim 15, wherein the controller further comprises an input device configured to receive user input to raise or lower the first voltage. ### Claim 20 (depends on 15) The system of claim 15, wherein the controller further comprises a display configured to output numeric values of the first and second voltages.