Abstract: For motor stator resistance calculation, a method estimates an output voltage using a Direct Current (DC) bus voltage and a duty ratio for a motor drive at a first switching frequency and at least one second switching frequency. The method measures an output current at the first switching frequency and the at least one second switching frequency. The method calculates a first stator resistance for the first switching frequency and at least one second stator resistance for the at least one second switching frequency. The method estimates a stator resistance at a DC condition based on the first stator resistance and the at least one second stator resistance. The method sets a dynamic compensation based on a stator resistance error between the first switching frequency and the at least one second switching frequency.

Abstract: Methods, non-transitory computer readable mediums, and power conversion systems with a controller configured to provide modulated inverter switching control signals at a first switching frequency in response to an inverter current being greater than a first threshold and less than a second threshold, the second threshold being greater than the first threshold. The controller is further configured to provide the inverter switching control signals at a second switching frequency in response to the inverter current being greater than the second threshold, and to provide the inverter switching control signals at a third switching frequency in response to the inverter current being less than the first threshold, where the second switching frequency is less than the first switching frequency and the third switching frequency is greater than the first switching frequency.

Abstract: For open loop phase pre-charge, an apparatus includes a Switching Mode Power Supply (SMPS) charging diode and a charge generator. The SMPS charging diode pre-charges an SMPS to a regulation set point from at least one phase of an Alternating Current (AC) voltage. The charge generator is powered by the pre-charged SMPS. In response to detecting the regulation set point iteratively, the charge generator detects a specified phase angle of the AC voltage. In response to the specified phase angle, the charge generator iteratively generates a charging voltage during positive voltage interval that charges a Direct Current (DC) bus capacitor to a target DC bus voltage within a charging time interval. At least a portion of the charge generator comprises one or more of hardware and executable code, the executable code stored on one or more computer readable storage media.

Abstract: Methods, non-transitory computer readable mediums, and power conversion systems with a controller configured to provide modulated inverter switching control signals at a first switching frequency in response to an inverter current being greater than a first threshold and less than a second threshold, the second threshold being greater than the first threshold. The controller is further configured to provide the inverter switching control signals at a second switching frequency in response to the inverter current being greater than the second threshold, and to provide the inverter switching control signals at a third switching frequency in response to the inverter current being less than the first threshold, where the second switching frequency is less than the first switching frequency and the third switching frequency is greater than the first switching frequency.

Abstract: For motor stator resistance calculation, a method estimates an output voltage using a Direct Current (DC) bus voltage and a duty ratio for a motor drive at a first switching frequency and at least one second switching frequency. The method measures an output current at the first switching frequency and the at least one second switching frequency. The method calculates a first stator resistance for the first switching frequency and at least one second stator resistance for the at least one second switching frequency. The method estimates a stator resistance at a DC condition based on the first stator resistance and the at least one second stator resistance. The method sets a dynamic compensation based on a stator resistance error between the first switching frequency and the at least one second switching frequency.

Abstract: A power conversion system includes a sensing circuit to sense a system voltage of a DC bus circuit with a first DC bus terminal with a first voltage positive relative to a second voltage of a second DC bus terminal. The sensing circuit includes a first capacitor having a first terminal coupled to the second DC bus terminal, and a second terminal; a second capacitor having a first terminal coupled to the second terminal of the first capacitor, and a second terminal coupled to a reference node; and a resistive divider circuit coupled across the first capacitor and having an output terminal that delivers a voltage signal corresponding to a voltage across the first capacitor.

Abstract: Power converters, protection systems and methods to protect a precharge circuit in which a precharge resistor voltage is indirectly monitored during a normal operating mode, and a rectifier and an inverter are selectively disabled in response to the indirectly measured precharge resistor voltage indicating a fault in a precharge circuit SCR.

Abstract: An active rectifier includes first and second DC nodes, a switching circuit, and a controller configured to compute a voltage reference according to a load signal of the DC output, and a non-linear relationship between a load condition of the DC output and a DC bus voltage at the DC output, and to generate rectifier switching control signals according to the voltage reference to cause the switching circuit to convert AC input power from the AC input to control the DC bus voltage at the DC output.

Abstract: An active rectifier includes first and second DC nodes, a switching circuit, and a controller configured to compute a voltage reference according to a load signal of the DC output, and a non-linear relationship between a load condition of the DC output and a DC bus voltage at the DC output, and to generate rectifier switching control signals according to the voltage reference to cause the switching circuit to convert AC input power from the AC input to control the DC bus voltage at the DC output.

Abstract: A power conversion system includes a controller that generates switching control signals according to duty cycles for a current switching control cycle, and adjusts the duty cycles by a non-zero offset value according to a modulation index in response to the modulation index exceeding a non-zero threshold. A method includes computing first duty cycles according to a modulation index, generating a plurality of switching control signals according to the first duty cycles in response to the modulation index being less than or equal to a non-zero threshold, computing second duty cycles offset from the first duty cycles and generating the plurality of switching control signals according to the second duty cycles in response to the modulation index exceeding the non-zero threshold.

Abstract: A method and controller to automatically determine a grounding condition of a motor drive, in which an inverter is operated at a predetermined frequency while a load resistor is connected between a single phase of a motor drive inverter output and a reference node, a leakage flux linkage value is computed according to a neutral-ground voltage of the motor drive, and a processor determines whether the motor drive is solid grounded, high-resistance grounded, or floating according to the leakage flux linkage value. In certain examples, the processor automatically turns the inverter off while the load resistor is connected between the single phase of the inverter output and the reference node, and automatically determines whether the motor drive is delta corner grounded according to the neutral-ground voltage.

Abstract: Power conversion systems and a controller thereof includes a first processing system that computes phase references for respective phase lines of an inverter according to a feedback value, a setpoint value, and a scaling factor to emulate a scaled frequency that is less than a switching frequency, and a second processing system that generates a carrier waveform having the switching frequency, receives the phase reference from the first processing system for each inverter phase line, and compares each phase reference with the carrier waveform to generate pulse width modulated switching control signals for switching devices of the inverter.

Abstract: Power conversion systems and filters therefor include conductive busbars, a first low frequency capacitor circuit coupled with the busbars at a first location proximate a filter input, a first inductor circuit with common mode cores extending around the busbars at a second location between the first location and a filter output, a second low frequency capacitor circuit coupled with the busbars at a third location between the second location and the filter output, a second inductor circuit with second common mode cores extending around the busbars at a fourth location between the third location and the filter output, a third low-frequency capacitor circuit coupled with the busbars at a fifth location between the fourth location and the filter output, and a high frequency fourth capacitor circuit, coupled with one of the busbars at the fifth location.

Abstract: Motor drive power conversion systems are provided including a rectifier and a switching inverter, wherein the switching devices of the rectifier, the inverter and/or of a DC/DC converter are silicon carbide switches, such as silicon carbide MOSFETs. Driver circuits are provided for providing bipolar gate drive signals to the silicon carbide MOSFETs, including providing negative gate-source voltage for controlling the off state of enhancement mode low side drivers and positive gate-source voltage for controlling the off state of enhancement mode high side drivers.

Abstract: Disclosed examples include apparatus to couple a motor drive to a motor, including a cable with a first end coupled with an output of a motor drive, a second end coupled with a motor, a plurality of conductors to convey an output signal of the motor drive between the first and second ends to drive the motor, and a plurality of shields, with a conductive junction to couple tap points of at least two of the shields together. Resistors can be used to connect the tap points to the conductive junction to provide an impedance in series with the corresponding shield to reduce voltage stress to the motor or the cable. In certain examples, the shields include a semiconductor material to provide an impedance between the first end and the conductive junction to reduce voltage stress to the motor or the cable.

Abstract: Power converters, protection systems and methods to protect a precharge circuit in which a precharge resistor voltage is indirectly monitored during a normal operating mode, and a rectifier and an inverter are selectively disabled in response to the indirectly measured precharge resistor voltage indicating a fault in a precharge circuit SCR.

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: A method and controller to automatically determine a grounding condition of a motor drive, in which an inverter is operated at a predetermined frequency while a load resistor is connected between a single phase of a motor drive inverter output and a reference node, a leakage flux linkage value is computed according to a neutral-ground voltage of the motor drive, and a processor determines whether the motor drive is solid grounded, high-resistance grounded, or floating according to the leakage flux linkage value. In certain examples, the processor automatically turns the inverter off while the load resistor is connected between the single phase of the inverter output and the reference node, and automatically determines whether the motor drive is delta corner grounded according to the neutral-ground voltage.

Abstract: Power conversion systems, disclosed examples include power conversion systems, ground fault detection apparatus and methods to detect and identify ground faults in a power conversion system using AC coupling to sense a system voltage to determine a leakage flux linkage, and to identify a faulted converter phase based on a phase shift angle of the leakage flux linkage.

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.