Abstract: A variable speed drive includes a converter connected to an AC power source, a DC link connected to the converter, and an inverter connected to the DC link. The inverter converts DC voltage into an output AC power having a variable voltage and frequency. The inverter includes at least one power electronics module and associated control circuitry; a heat sink in thermal communication with the power electronics module and in fluid communication with a manifold. The manifold includes a tubular member having at least one vertical member portion and at least one horizontal member portion in fluid communication. A plurality of ports conduct cooling fluid into and out of the manifold. A bracket attaches the manifold to a structural frame. Brackets are provided for attachment of power electronics modules to the manifold.

Abstract: A system or method for a VSD with an active converter including a controller, an inductor, an active converter, a DC link, and an inverter. The active converter is controlled to receive an input AC voltage and output a boosted DC voltage to a DC link, up to 850 VDC, the active converter using only low voltage semiconductor switches to provide the 850 VDC DC link voltage. The controller is configured to operate with a reactive input current magnitude equal to zero at a predetermined system load, and at system loads less than the predetermined system load, to introduce a reactive input current that results in a converter voltage having a magnitude less than the input voltage, wherein the vector sum of the input voltage and an inductor voltage is equal to the converter voltage.

Abstract: A variable speed drive includes a converter connected to an AC power source, a DC link connected to the converter, and an inverter connected to the DC link. The inverter converts DC voltage into an output AC power having a variable voltage and frequency. The inverter includes at least one power electronics module and associated control circuitry; a heat sink in thermal communication with the power electronics module and in fluid communication with a manifold. The manifold includes a tubular member having at least one vertical member portion and at least one horizontal member portion in fluid communication. A plurality of ports conduct cooling fluid into and out of the manifold. A bracket attaches the manifold to a structural frame. Brackets are provided for attachment of power electronics modules to the manifold.

Abstract: A grounding system for a semiconductor module of a variable speed drive includes a first conductive layer, a second conductive layer; a substrate disposed between the first conductive layer and the second conductive layer; and a base attached to the second conductive layer, the base being connected to earth ground via a grounding harness. The first conductive layer is in electrical contact with the semiconductor module and the substrate, and electrically insulated from the second conductive layer by the substrate. The second conductive layer is in electrical contact with the substrate and disposed between the substrate and the base in electrical communication with an earth ground. The first conductive layer, the substrate and the second conductive layer form a capacitance path between the semiconductor module and the base as well as electrical conductors and the base for reduction circulating currents within the semiconductor module.

Abstract: A chiller system is provided with a compressor, a condenser, and an evaporator connected in a closed refrigerant loop. A motor is connected to the compressor to power the compressor. A variable speed drive is connected to the motor. The variable speed drive is arranged to receive an input AC power at a fixed input AC voltage and a fixed input frequency and provide an output power at a variable voltage and variable frequency to the motor. The variable voltage has a maximum voltage greater in magnitude than the fixed input AC voltage and the variable frequency has a maximum frequency greater than the fixed input frequency. The variable speed drive includes a converter connected to an AC power source providing the input AC voltage, the converter is arranged to convert the input AC voltage to a DC voltage. A DC link is connected to the converter. The DC link is arranged to filter and store the DC voltage from the converter. An inverter is connected to the DC link.

Abstract: A drive system for a compressor of a chiller system includes a variable speed drive. The variable speed drive receives an input AC power at a fixed input AC voltage and a fixed input frequency, and provides an output AC power at a variable voltage and variable frequency. The variable speed drive includes a converter connected to an AC power source. The converter is arranged to convert the input AC voltage to a DC voltage. A DC link is connected to the converter and configured to filter and store the DC voltage from the converter. An inverter is connected to the DC link. A motor is connectable to the compressor for powering the compressor. A controller is arranged to control switching in the converter and the inverter. The controller is arranged to apply randomized pulse width modulation to vary the switching frequency of transistors in the converter and the inverter at each switching cycle. The motor may be a permanent magnet synchronous motor.

Abstract: A drive system for a compressor of a chiller system includes a variable speed drive. The variable speed drive is arranged to receive an input AC power at a fixed AC input voltage and fixed input frequency and provide an output AC power at a variable voltage and variable frequency. The variable speed drive includes a converter connected to an AC power source providing the input AC voltage. The converter is arranged to convert the input AC voltage to a DC voltage. A DC link is connected to the converter. The DC link is arranged to filter and store the DC voltage from the converter. A first inverter and a second inverter are each connected to the DC link. A motor includes stator windings connected between the first inverter and the second inverter to power the motor by the output AC power from the first inverter and the second inverter. The motor is connectable to a compressor of the chiller system to power the compressor. The motor may be a permanent magnet synchronous motor.

Abstract: A hybrid motor for powering a compressor of a chiller system includes a first rotor portion and a first stator portion configured as a permanent magnet motor and a second rotor portion and a second stator portion configured as a reluctance motor. The second rotor portion includes a reluctance-type rotor, and the second stator portion includes electromagnetic windings capable of inducing a rotary magnetic field. The first rotor portion and the second rotor portion are attached to a common drive shaft. The reluctance motor is arranged to generate start-up torque and initiate rotation of the drive shaft until the drive shaft achieves a predetermined rotational speed. The permanent magnet motor is arranged to power the drive shaft between the predetermined rotational speed and a maximum rotational speed.

Abstract: A drive system for a compressor of a chiller system includes a variable speed drive. The variable speed drive is arranged to receive an input AC voltage at a fixed AC input voltage and provide an output AC power at a variable voltage and variable frequency. The variable speed drive includes a converter connected to an AC power source providing the input AC voltage. The converter is arranged to convert the input AC voltage to a DC voltage. A DC link is connected to the converter. The DC link filters and stores the DC voltage from the converter. An inverter is connected to the DC link. A motor connectable to the compressor for powering the compressor. An active filter connected in parallel with the motor. The active filter is arranged to generate high frequency currents having a magnitude and opposite polarity, with respect to the output AC power of the variable speed drive. The high frequency currents generated by active filter substantially cancel out high frequency currents flowing into the motor.

Abstract: Systems and methods for improved VSDs are provided. One embodiment relates to an apparatus for common mode and differential mode filtering for motor or compressor bearing protection when operating with VSDs, including conducted EMI/RFI input power mains mitigation. Another embodiment relates to a method to extend the synchronous operation of an Active Converter to the AC mains voltage during complete line dropout. Another embodiment relates to an Active Converter-based Variable Speed Drive system with Improved Full Speed Efficiency.

Abstract: Systems and methods for improved VSDs are provided. One embodiment relates to an apparatus for common mode and differential mode filtering for motor or compressor bearing protection when operating with VSDs, including conducted EMI/RFI input power mains mitigation. Another embodiment relates to a method to extend the synchronous operation of an Active Converter to the AC mains voltage during complete line dropout. Another embodiment relates to an Active Converter-based Variable Speed Drive system with Improved Full Speed Efficiency.

Abstract: A grounding system for a semiconductor module of a variable speed drive includes a first conductive layer, a second conductive layer; a substrate disposed between the first conductive layer and the second conductive layer; and a base attached to the second conductive layer, the base being connected to earth ground via a grounding harness. The first conductive layer is in electrical contact with the semiconductor module and the substrate, and electrically insulated from the second conductive layer by the substrate. The second conductive layer is in electrical contact with the substrate and disposed between the substrate and the base in electrical communication with an earth ground. The first conductive layer, the substrate and the second conductive layer form a capacitance path between the semiconductor module and the base as well as electrical conductors and the base for reduction circulating currents within the semiconductor module.

Abstract: A hybrid motor for powering a compressor of a chiller system includes a first rotor portion and a first stator portion configured as a permanent magnet motor and a second rotor portion and a second stator portion configured as a reluctance motor. The second rotor portion includes a reluctance-type rotor, and the second stator portion includes electromagnetic windings capable of inducing a rotary magnetic field. The first rotor portion and the second rotor portion are attached to a common drive shaft. The reluctance motor is arranged to generate start-up torque and initiate rotation of the drive shaft until the drive shaft achieves a predetermined rotational speed. The permanent magnet motor is arranged to power the drive shaft between the predetermined rotational speed and a maximum rotational speed.

Abstract: A drive system for a compressor of a chiller system includes a variable speed drive. The variable speed drive is arranged to receive an input AC power at a fixed AC input voltage and fixed input frequency and provide an output AC power at a variable voltage and variable frequency. The variable speed drive includes a converter connected to an AC power source providing the input AC voltage. The converter is arranged to convert the input AC voltage to a DC voltage. A DC link is connected to the converter. The DC link is arranged to filter and store the DC voltage from the converter. A first inverter and a second inverter are each connected to the DC link. A motor includes stator windings connected between the first inverter and the second inverter to power the motor by the output AC power from the first inverter and the second inverter. The motor is connectable to a compressor of the chiller system to power the compressor. The motor may be a permanent magnet synchronous motor.

Abstract: A drive system for a compressor of a chiller system includes a variable speed drive. The variable speed drive receives an input AC power at a fixed input AC voltage and a fixed input frequency, and provides an output AC power at a variable voltage and variable frequency. The variable speed drive includes a converter connected to an AC power source. The converter is arranged to convert the input AC voltage to a DC voltage. A DC link is connected to the converter and configured to filter and store the DC voltage from the converter. An inverter is connected to the DC link. A motor is connectable to the compressor for powering the compressor. A controller is arranged to control switching in the converter and the inverter. The controller is arranged to apply randomized pulse width modulation to vary the switching frequency of transistors in the converter and the inverter at each switching cycle. The motor may be a permanent magnet synchronous motor.

Abstract: A drive system for a compressor of a chiller system includes a variable speed drive. The variable speed drive is arranged to receive an input AC voltage at a fixed AC input voltage and provide an output AC power at a variable voltage and variable frequency. The variable speed drive includes a converter connected to an AC power source providing the input AC voltage. The converter is arranged to convert the input AC voltage to a DC voltage. A DC link is connected to the converter. The DC link filters and stores the DC voltage from the converter. An inverter is connected to the DC link. A motor connectable to the compressor for powering the compressor. An active filter connected in parallel with the motor. The active filter is arranged to generate high frequency currents having a magnitude and opposite polarity, with respect to the output AC power of the variable speed drive. The high frequency currents generated by active filter substantially cancel out high frequency currents flowing into the motor.