Abstract: A component includes a power suspension module that suspends providing power from a DC source to a DC link capacitor and from the capacitor to a load. A bleeding resistor is connected in parallel with the capacitor and an auxiliary power supply draws power from the capacitor. The component includes a measurement module that measures a first, second and third capacitor voltage at a first, second, time, and third time in response suspending power between the DC source and the load. The component includes a capacitance module that uses bleeding resistor resistance, the voltages and the times to determine a current capacitance of the capacitor, a capacitance comparison module that compares the current capacitance with an initial capacitance of the capacitor, and an alert module that sends an alert in response to determining that a difference between the current capacitance and the initial capacitance is above a capacitance degradation threshold.

Abstract: Power conversion systems and methods to control a multiphase multilevel regenerative power converter with multilevel phase circuits that individually include multiple regenerative power stages with respective power stage outputs connected in series, each of the multiple regenerative power stages comprising a DC link circuit a switching rectifier coupled between a respective transformer secondary circuit and the DC link circuit, and a switching inverter coupled between the DC link circuit and the respective power stage output, including a controller that provides inverter switching control signals to control the respective switching inverters, provides rectifier switching control signals to control the respective switching rectifiers, and controls a non-zero phase relationship between the rectifier switching control signals of the respective switching rectifiers.

Abstract: A system is provided for driving multiple motors. The system includes multiple cascaded H-bridge (CHB) power inverters, a DC bus, and multiple neutral point converter/inverters. Each of the multiple CHB power inverters is connected to a respective motor at one or more AC terminals of the CHB power inverter. Each of the multiple CHB power inverters includes one or more DC terminals configured to receive DC power. Each of the multiple neutral point converter/inverters is connected to a respective CHB power inverter at one or more neutral terminals of the respective CHB power inverter and connected to the DC bus.

Abstract: Power conversion systems and methods to control a multiphase multilevel regenerative power converter with multilevel phase circuits that individually include multiple regenerative power stages with respective power stage outputs connected in series, each of the multiple regenerative power stages comprising a DC link circuit a switching rectifier coupled between a respective transformer secondary circuit and the DC link circuit, and a switching inverter coupled between the DC link circuit and the respective power stage output, including a controller that provides inverter switching control signals to control the respective switching inverters, provides rectifier switching control signals to control the respective switching rectifiers, and controls a non-zero phase relationship between the rectifier switching control signals of the respective switching rectifiers.

Abstract: A regenerative power conversion system with a phase shift transformer having a primary circuit and N secondary sets of M secondary circuits, a controller synchronizes rectifier switching control signals of individual regenerative power stages to a phase angle of a corresponding one of the secondary circuits based on a feedback signal of the primary circuit during regenerative operation of the power conversion system.

Abstract: A system is provided for driving multiple motors. The system includes multiple cascaded H-bridge (CHB) power inverters, a DC bus, and multiple neutral point converter/inverters. Each of the multiple CHB power inverters is connected to a respective motor at one or more AC terminals of the CHB power inverter. Each of the multiple CHB power inverters includes one or more DC terminals configured to receive DC power. Each of the multiple neutral point converter/inverters is connected to a respective CHB power inverter at one or more neutral terminals of the respective CHB power inverter and connected to the DC bus.

Abstract: A power conversion system and controller configured to generate a real average DC current reference based on a DC bus voltage of a DC link circuit and a DC bus voltage setpoint, generate real and reactive ripple current references based on the DC bus voltage of the DC link circuit and a ripple angle of the DC link circuit, and generate rectifier switching control signals to operate rectifier switching devices based on the real average DC current reference and the real and reactive ripple current references.

Abstract: A power conversion system and controller configured to generate a real average DC current reference based on a DC bus voltage of a DC link circuit and a DC bus voltage setpoint, generate real and reactive ripple current references based on the DC bus voltage of the DC link circuit and a ripple angle of the DC link circuit, and generate rectifier switching control signals to operate rectifier switching devices based on the real average DC current reference and the real and reactive ripple current references.

Abstract: Power conversion systems and methods to control a multiphase multilevel regenerative power converter with multilevel phase circuits that individually include multiple regenerative power stages with respective power stage outputs connected in series, the individual power stages comprising a DC link circuit a switching rectifier coupled between a respective transformer secondary circuit and the DC link circuit, and a switching inverter coupled between the DC link circuit and the respective power stage output, including a controller that provides inverter switching control signals to control the respective switching inverters, provides rectifier switching control signals to control the respective switching rectifiers, and controls a non-zero phase relationship between the rectifier switching control signals of the respective switching rectifiers.

Abstract: Multilevel power converters, power cells and methods are presented for selectively bypassing a power stage of a multilevel inverter circuit, in which a single relay or contactor includes first and second normally closed output control contacts coupled between a given power cell switching circuit and the given power cell output, along with a normally open bypass contact coupled across the power stage output, with a local or central controller energizing the coil of the relay or contactor of a given cell to bypass that cell.

Abstract: Multilevel power converters, power cells and methods are presented for selectively bypassing a power stage of a multilevel inverter circuit, in which a single relay or contactor includes first and second normally closed output control contacts coupled between a given power cell switching circuit and the given power cell output, along with a normally open bypass contact coupled across the power stage output, with a local or central controller energizing the coil of the relay or contactor of a given cell to bypass that cell.

Abstract: Multilevel power converters, power cells and methods are presented for selectively bypassing a power stage of a multilevel inverter circuit, in which a single relay or contactor includes first and second normally closed output control contacts coupled between a given power cell switching circuit and the given power cell output, along with a normally open bypass contact coupled across the power stage output, with a local or central controller energizing the coil of the relay or contactor of a given cell to bypass that cell.

Abstract: Power conversion systems, control apparatus, methods and computer readable mediums to operate a multiphase multilevel inverter that includes M inverter phase leg circuits that individually include N inverter stages with corresponding stage outputs connected in series between a reference node and a corresponding inverter phase output node, M being greater than 2, N being greater than 2, in which the stage outputs of a selected set of M of the inverter stages are bypassed, where the selected set includes a single inverter stage from each of the inverter phase leg circuits, and the selected set of inverter stages are connected to secondaries of a phase shift transformer at M different phase relationships to control harmonic distortion in a current of the transformer primary in response to a suspected inverter stage fault.

Abstract: Disclosed examples include methods, power converters and damping circuits to control damping of an input filter circuit, in which a low-voltage secondary winding is wound around a common core with a primary winding connected between an AC input and a rectifier input of the converter, where the secondary winding is coupled in a series circuit with a damping resistor and a switch, and a controller selectively closes the switch with a controlled on-time at system power up and/or in response to detection of oscillation or transients in the power converter.

Abstract: Multilevel power converters, power cells and methods are presented for selectively bypassing a power stage of a multilevel inverter circuit, in which a single relay or contactor includes first and second normally closed output control contacts coupled between a given power cell switching circuit and the given power cell output, along with a normally open bypass contact coupled across the power stage output, with a local or central controller energizing the coil of the relay or contactor of a given cell to bypass that cell.

Abstract: For power conversion, a power conversion system includes a plurality of power converters and a phase shifting transformer. The phase shifting transformer includes 3-phase primary windings, a core and a plurality of m secondary winding groups. Each of the secondary winding groups includes n secondary windings in electromagnetic communication with a corresponding primary winding and feeding the plurality of power converters. Phase angle sets of the secondary winding groups are all different with a non-zero secondary winding phase shift between any two secondary winding groups.

Abstract: Disclosed examples include methods, power converters and damping circuits to control damping of an input filter circuit, in which a low-voltage secondary winding is wound around a common core with a primary winding connected between an AC input and a rectifier input of the converter, where the secondary winding is coupled in a series circuit with a damping resistor and a switch, and a controller selectively closes the switch with a controlled on-time at system power up and/or in response to detection of oscillation or transients in the power converter.

Abstract: Apparatus to provide bypass redundancy for a multiphase multilevel inverter including a spare inverter stage and a switch circuit to connect the spare inverter stage between a selected one of the inverter phase first nodes having a bypassed stage and a common connection node, and to connect the remaining inverter phase first nodes with the common connection node.

Abstract: For power conversion, a power conversion system includes a plurality of power converters and a phase shifting transformer. The phase shifting transformer includes 3-phase primary windings, a core and a plurality of m secondary winding groups. Each of the secondary winding groups includes n secondary windings in electromagnetic communication with a corresponding primary winding and feeding the plurality of power converters. Phase angle sets of the secondary winding groups are all different with a non-zero secondary winding phase shift between any two secondary winding groups.

Abstract: Power converters are presented with one or more sparse multilevel actively clamped (SMAC) power converter stages, where the individual stages include an integer number N capacitors or DC voltage sources coupled between stage DC inputs to provide L=N+1 converter stage DC voltage nodes, with a switching circuit having no more than L*(L?1) switching devices and no flying or floating DC storage capacitors, where N is greater than 2.