US 12,068,692 B2
Multi slope output impedance controller to reduce current imbalance in a masterless configuration of n parallel-connected power converters and improve load regulation in a single power converter
Marty Perry, Tucson, AZ (US); and Robert J. Schaller, Tucson, AZ (US)
Assigned to Raytheon Company, Tewksbury, MA (US)
Filed by Raytheon Company, Waltham, MA (US)
Filed on Mar. 14, 2022, as Appl. No. 17/694,338.
Claims priority of provisional application 63/289,884, filed on Dec. 15, 2021.
Prior Publication US 2023/0188040 A1, Jun. 15, 2023
Int. Cl. H02M 3/158 (2006.01); H02M 1/00 (2007.01); H02M 1/36 (2007.01)
CPC H02M 3/1584 (2013.01) [H02M 1/0009 (2021.05); H02M 1/36 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A regulated power supply configured to supply power to a common load connected at a load terminal, said power supply comprising:
N parallel-connected power supplies in a masterless configuration configured to supply power to the load terminal where N is an integer of one or more, each said power supply comprising,
a power converter responsive to a command Vx_n to generate a controllable voltage Vc_n across an effective output impedance Zeff_n to supply an output current Iout_n at an output that is coupled through an external output impedance Zext_n to the load terminal;
a negative feedback controller configured to provide a negative feedback loop in which a regulated voltage Vreg_n at the output is compared to a setpoint voltage Vsetpoint_n to control the command Vx_n to maintain regulation of the regulated voltage Vreg_n and an output voltage Vout at the load terminal for varying load currents IL; and
a multi slope output impedance controller responsive to a current Isense_n indicative of the output current Iout_n to control the setpoint voltage Vsetpoint_n such that the regulated voltage Vreg_n is reduced as the output current Iout_n is increased to facilitate load current sharing among the plurality of power supplies, command a high value of the effective output impedance Zeff_n when the output current Iout_n is less than a specified value to reduce a current imbalance Ib between the power supplies and to command a low value of the effective output impedance Zeff_n when the output current Iout_n is greater than the specified value to improve the regulation of the output voltage Vout
wherein the multi slope output impedance controller is responsive to a mode input to select single or multiple power converter configurations,
wherein in the multiple configuration of N>1, the controller is configured to reduce the setpoint voltage Vsetpoint_n as the output current Iout_n increases to facilitate load current sharing among the plurality of power supplies and to command the high value of the Zeff_n for the Iout_n less than the specified value to reduce the current imbalance Ib and to command the low value of the Zeff_n for the Iout_n greater than the specified value to improve load regulation;
wherein in the single configuration of N=1, the controller is configured to set a negative value for the Zeff_n to substantially offset a positive value of the Zext_n to increase the setpoint voltage Vsetpoint_n as the output current Iout_n increases to improve load regulation.