Abstract: A gradient amplifier for driving a gradient coil is disclosed. The gradient amplifier includes a direct current (DC) bus for receiving DC voltage generated from a series resonant converter, an inverter coupled to the DC bus configured to receive the DC voltage at the DC bus and convert the DC voltage to generate an output voltage to be applied to the gradient coil, and an inverter controller coupled to the inverter. The inverter controller is configured to generate control signals to control operation of the inverter based at least on a DC voltage feedback signal measured at the DC bus, an output voltage feedback signal measured at the output of the inverter, and a reference output voltage signal indicative of a desired voltage to be achieved at the output of the inverter.

Abstract: A resonant power supply is provided. The resonant power supply comprises a series resonant converter configured to convert an input DC voltage to an output DC voltage to generate an output DC voltage. The series resonant converter includes a switching stage, a resonant inductor, a resonant capacitor, and an isolation transformer. The resonant power supply further comprises a converter controller configured to obtain an actual trajectory radius signal based on a resonant inductor current, a resonant capacitor voltage, and a voltage in association with the isolation transformer. The converter controller is further configured to generate a trajectory radius command signal based on a DC voltage command signal and a DC voltage feedback signal, and to generate control signals to be applied to the switching stage based on the actual trajectory radius signal and the trajectory radius command signal.

Abstract: A distributed photovoltaic (PV) power plant includes a plurality of distributed dc-dc converters. The dc-dc converters are configured to switch in coordination with one another such that at least one dc-dc converter transfers power to a common dc-bus based upon the total system power available from one or more corresponding strings of PV modules. Due to the coordinated switching of the dc-dc converters, each dc-dc converter transferring power to the common dc-bus continues to operate within its optimal efficiency range as well as to optimize the maximum power point tracking in order to increase the energy yield of the PV power plant.

Abstract: Embodiments of the present disclosure include a magnetic resonant imaging (MRI) system including a gradient driver configured to deliver a pulse sequence to gradient coils in the MRI system. The gradient driver may be interleaved, and may include two or more interleaved drivers, such that a high amplitude pulse may be output by operating the two interleaved parts of the gradient driver while spreading the electrical loss and maintaining the thermal stability of the system. In one embodiment, each interleaved driver may be rated to output approximately half a maximum amplitude of a current utilized by the gradient coil, and only one interleaved driver may be in operation if only one interleaved driver is sufficient for delivering a necessary pulse to the coils. Further, the interleaved drivers may alternate in operation to maintain thermal stability in the switching semiconductors of the gradient driver.

Abstract: Systems and methods for controlling an electrical power supply are provided. One system includes an input configured for receiving voltage measurement signals for the power supply and a controller for one or more electrical phases of the power supply. The controller includes an integrator configured to integrate the received voltage measurement signals and to generate integrated control signals or integrated error signals. The controller is configured to generate an output signal using the integrated control signals or the integrated error signals. The system also includes an output configured to output the output signal to control switching of the power supply.

Abstract: In one embodiment, a system includes a gradient coil driver configured to supply electrical signals to a gradient coil of a magnetic resonance imaging system. The gradient coil driver includes an electronic circuit. The electronic circuit includes a first H-bridge circuit electrically coupled to a power source. The first H-bridge includes a plurality of metal-oxide-semiconductor field-effect transistor (MOSFET) switches; and a plurality of diodes electrically coupled in parallel with each MOSFET switch. Each diode of the plurality of diodes is configured to conduct current to cause zero voltage potential across a source and a drain of one of the plurality of MOSFET switches. The first H-bridge also includes a load configured to regulate currents flowing through each of the plurality of diodes and each MOSFET switch of the plurality of MOSFET switches.

Abstract: A gradient amplifier system is presented. An embodiment of a gradient amplifier system that includes a power stage having a plurality of bridge amplifiers, where each of the plurality of bridge amplifiers operates at a first switching frequency. The gradient amplifier system further includes a gradient coil coupled to an output terminal of the power stage and configured to produce a magnetic field proportional to a coil current signal supplied by the power stage. In addition, the gradient amplifier system includes a controller stage coupled to an input terminal of the power stage and configured to generate a pulse width modulated gate signal based on the coil current signal and a reference current signal, where the pulse width modulated gate signal is generated at a second switching frequency upon occurrence of a slew rate associated with the reference current signal is below a determined threshold rate and an amplitude level associated with the reference current signal is above a determined level.

Abstract: A power generation system configured to provide direct current (DC) power to a DC link is described. The system includes a first power generation unit configured to output DC power. The system also includes a first DC to DC converter comprising an input section and an output section. The output section of the first DC to DC converter is coupled in series with the first power generation unit. The first DC to DC converter is configured to process a first portion of the DC power output by the first power generation unit and to provide an unprocessed second portion of the DC power output of the first power generation unit to the output section.

Abstract: A distributed photovoltaic (PV) power plant includes a plurality of distributed dc-dc converters. The dc-dc converters are configured to switch in coordination with one another such that at least one dc-dc converter transfers power to a common dc-bus based upon the total system power available from one or more corresponding strings of PV modules. Due to the coordinated switching of the dc-dc converters, each dc-dc converter transferring power to the common dc-bus continues to operate within its optimal efficiency range as well as to optimize the maximum power point tracking in order to increase the energy yield of the PV power plant.

Abstract: A gradient amplifier system is presented. An embodiment of a gradient amplifier system that includes a power stage having a plurality of bridge amplifiers, where each of the plurality of bridge amplifiers operates at a first switching frequency. The gradient amplifier system further includes a gradient coil coupled to an output terminal of the power stage and configured to produce a magnetic field proportional to a coil current signal supplied by the power stage. In addition, the gradient amplifier system includes a controller stage coupled to an input terminal of the power stage and configured to generate a pulse width modulated gate signal based on the coil current signal and a reference current signal, where the pulse width modulated gate signal is generated at a second switching frequency upon occurrence of a slew rate associated with the reference current signal is below a determined threshold rate and an amplitude level associated with the reference current signal is above a determined level.

Abstract: A power generation system configured to provide direct current (DC) power to a DC link is described. The system includes a first power generation unit configured to output DC power. The system also includes a first DC to DC converter comprising an input section and an output section. The output section of the first DC to DC converter is coupled in series with the first power generation unit. The first DC to DC converter is configured to process a first portion of the DC power output by the first power generation unit and to provide an unprocessed second portion of the DC power output of the first power generation unit to the output section.

Abstract: A power generation system includes photovoltaic (PV) modules for generating power and power converters coupled to receive power from the PV modules. The power generation system further includes converter controllers to control the power converters, each converter controller includes a maximum power point tracking control element. A master controller in the power generation system is configured to coordinate power outputs of the power converters by controlling the timing and numbers of power converters having power-voltage (P-V) curves sweeping between maximum power points and power points off the maximum power points.

Abstract: Embodiments of the present disclosure include a magnetic resonant imaging (MRI) system including a gradient driver configured to deliver a pulse sequence to gradient coils in the MRI system. The gradient driver may be interleaved, and may include two or more interleaved drivers, such that a high amplitude pulse may be output by operating the two interleaved parts of the gradient driver while spreading the electrical loss and maintaining the thermal stability of the system. In one embodiment, each interleaved driver may be rated to output approximately half a maximum amplitude of a current utilized by the gradient coil, and only one interleaved driver may be in operation if only one interleaved driver is sufficient for delivering a necessary pulse to the coils. Further, the interleaved drivers may alternate in operation to maintain thermal stability in the switching semiconductors of the gradient driver.

Abstract: One embodiment is a gate drive circuitry for switching a semiconductor device having a non-isolated input, the gate drive circuitry having a first circuitry configured to turn-on the semiconductor device by imposing a current on a gate of the semiconductor device so as to forward bias an inherent parasitic diode of the semiconductor device. There is a second circuitry configured to turn-off the semiconductor device by imposing a current on the gate of the semiconductor device so as to reverse bias the parasitic diode of the semiconductor device wherein the first circuitry and the second circuitry are coupled to the semiconductor device respectively through a first switch and a second switch.

Abstract: One embodiment is a gate drive circuitry for switching a semiconductor device having a non-isolated input, the gate drive circuitry having a first circuitry configured to turn-on the semiconductor device by imposing a current on a gate of the semiconductor device so as to forward bias an inherent parasitic diode of the semiconductor device. There is a second circuitry configured to turn-off the semiconductor device by imposing a current on the gate of the semiconductor device so as to reverse bias the parasitic diode of the semiconductor device wherein the first circuitry and the second circuitry are coupled to the semiconductor device respectively through a first switch and a second switch.

Abstract: A power supply having an input, wherein the power supply includes a multi-winding transformer having an input and a plurality of outputs, and a plurality of rectifiers to provide a plurality of DC output voltages, wherein each rectifier is coupled to an output of the multi-winding transformer. The power supply further includes a regulator circuit coupled between the transformer input and one of the transformer outputs, and configured to regulate an input voltage to the multi-winding transformer to minimize a variance of each rectifier DC output voltage.

Abstract: A power supply having an input, wherein the power supply includes a multi-winding transformer having an input and a plurality of outputs, and a plurality of rectifiers to provide a plurality of DC output voltages, wherein each rectifier is coupled to an output of the multi-winding transformer. The power supply further includes a regulator circuit coupled between the transformer input and one of the transformer outputs, and configured to regulate an input voltage to the multi-winding transformer to minimize a variance of each rectifier DC output voltage.

Abstract: A boost inductor value reduction circuit is integrated into a traditional boost power converter to greatly reduce undesirable high frequency harmonics from being fed back to the input side of the boost power converter. The boost inductor value reduction circuit is very small when compared with traditional filter techniques, is less costly than traditional filter techniques, and does not degrade the boost power converter control performance. It can also be used to reduce the size of the boost inductor without compromising the converter performance for use in energy efficient sensitive applications such as photovoltaic inverters.

Abstract: A circuit for driving the current for inductive loads such as a electron beam deflection coil for an x-ray generator system. The circuit includes two selectable voltage levels which are provided by a high level voltage source and a low level voltage source or, alternatively, by a low level voltage source and a boosting converter. A plurality of switches for selecting the voltage source allow only one voltage source to be connected to the load at any given time, and for selecting the polarity of the current through the coil. The high level voltage source is selected when the load is charging or discharging. The low level voltage source is selected when the load is operating in a constant current mode, where a high frequency switching device uses the low level voltage source to generate a pulse width modulation waveform according to a reference current duty cycle to control the voltage across the load.

Abstract: A circuit for driving the current for inductive loads such as an electron beam deflection coil for an x-ray generator system. The circuit includes two selectable voltage levels provided by a high level and a low level source. A plurality of switches selects the voltage level and determines the polarity of the current through the coil. The high level source is selected when the load is charging or discharging. The low level source is selected when the load is operating in a constant current mode, where a high frequency switching device controls the voltage through the load by switching the low level source to generate a PWM waveform according to a reference current duty cycle. A feedback loop monitors the current through the load to adjust the duty cycle of the PWM waveform to more accurately control the current through the load.