Abstract: Disclosed are gastroretentive, sustained-release tablet formulations comprising an active agent, such as pregabalin or a pharmaceutically acceptable form thereof, crospovidone, and a cationic copolymer based on dimethylaminoethyl methacrylate, butyl methacrylate, and methyl methacrylate random copolymer.

Abstract: Monitoring circuitry connectable to power conversion circuitry enclosed within packaging, the power conversion circuitry including terminals providing external connections to nodes of the power conversion circuitry enclosed within the packaging, the monitoring circuitry including: a comparator including a first input terminals connectable to first and second terminals of the power conversion circuitry and a second input terminal connected to a reference voltage, wherein the first and second terminals provide external connections to first and second nodes connected along respective current paths each connected to switching circuitry of the power conversion circuitry enclosed within the packaging, wherein the comparator detects a switch state of the switching circuitry based on a voltage generated at the first input terminal and the reference voltage; processing circuitry connected to the comparator and configured to monitor the power conversion circuitry based on the detected switch state and a signal of the p

Abstract: An electrical machine with a rotor coupled to a drive shaft of an engine; a DC electrical network; a power electronics converter connected, on a DC-side, to the DC electrical network, and, on an AC-side, to the electrical machine, the power electronics converter comprising a plurality of transistors and associated diodes connected in anti-parallel with the transistors; and a controller configured to control switching of the transistors so that the converter either inverts DC power to AC power or rectifies AC power to DC power. The controller is further configured, responsive to a determination that there is a fault in the DC electrical network, to operate in a fault mode in which the controller controls the switching of the transistors so that a fault current is shared between the transistors and the associated diodes.

Abstract: Electrical power systems having variable-voltage DC busses and methods of controlling voltage settings of such busses. One electrical power system comprises: a variable-voltage DC bus; a number N?2 of electrical machines, each electrical machine connected to the variable-voltage DC bus via one of a corresponding number N of converters, each electrical machine and corresponding converter having an index n=(1, . . . , N); and a controller configured to select a voltage setting Vdc_bus for the variable-voltage DC bus and to provide control signals to the converters to control the voltage setting of the variable-voltage DC bus according to the selected voltage setting Vdc_bus. The controller configured to select a voltage setting Vdc_bus greater than or equal to a minimum voltage requirement Vdc_min for the bus. The controller is configured to determine the minimum voltage requirement Vdc_min using present operating speeds of each of the N electrical machines.

Abstract: Electrical power distribution systems and methods of operating electrical power distribution systems are provided. One electrical power distribution system comprises: an electrical power storage unit; a transformer; a first bidirectional converter circuit connected between the electrical power storage unit and a first winding of the transformer; a first DC bus; a second DC bus; a second bidirectional converter circuit connected between the first DC bus and a second winding of the transformer; a third bidirectional converter circuit connected between the second DC bus and a third winding of the transformer; and a controller connected for control of the first, second and third converter circuits to distribute electrical power between the electrical power storage unit, the first DC bus and the second DC bus.

Abstract: A two-start helical heat exchanger comprises a helical baffle extending along a length of the heat exchanger and having first and second surfaces, wherein: the first surface of the baffle is arranged to provide a first helical fluid flow path for a first fluid; and the second surface of the baffle is arranged to provide a second helical fluid flow path for a second fluid, wherein the second fluid flow path is arranged in counter-flow with the first fluid flow path and a casing within which the baffle is mounted. The baffle is arranged such that first and second fluid flow paths are in thermal contact with each other through the baffle, and in thermal contact with the casing. The heat exchanger may be incorporated into a power converter, for example to cool the power converter. The heat exchanger may be used on an aircraft.

Abstract: Electrical power systems having variable-voltage DC busses and methods of controlling voltage settings of such busses. One electrical power system comprises: a variable-voltage DC bus; a number N?2 of electrical machines, each electrical machine connected to the variable-voltage DC bus via one of a corresponding number N of converters, each electrical machine and corresponding converter having an index n=(1, . . . , N); and a controller configured to select a voltage setting Vdc_bus for the variable-voltage DC bus and to provide control signals to the converters to control the voltage setting of the variable-voltage DC bus according to the selected voltage setting Vdc_bus. The controller configured to select a voltage setting Vdc_bus greater than or equal to a minimum voltage requirement Vdc_min for the bus. The controller is configured to determine the minimum voltage requirement Vdc_min using present operating speeds of each of the N electrical machines.

Abstract: An operating condition monitor (100) for monitoring an operating condition of a transistor-based power converter (102), comprising: a sensing apparatus (106) configured to measure a turn-off transient energy of the power converter (102), a processor (108) in communication with the sensing apparatus (106) to receive the measurement of the turn-off transient energy, the processor being configured to: compare the measurement of the turn-off transient energy to a threshold; and issue an event signal based on the comparison to the threshold meeting a comparison criterion. A method (200, 200?) of monitoring an operating state of a transistor-based power converter is also disclosed.

Abstract: A system, method and machine-readable instructions for monitoring a power electronics device. The system involves a semiconductor device, at least one sensor and a processor. The processor is configured to monitor a junction temperature of the semiconductor device by determining from the at least one sensor an on-state resistance of the semiconductor device and calculating the junction temperature of the semiconductor device according to a relationship between the on-state resistance of the semiconductor device and the junction temperature of the semiconductor device. The processor may apply an ageing coefficient to the on-state resistance.

Abstract: A method determines a generator system load and/or rotor angle. The generator system has a generator with a generator terminal outputting electrical power generated by the generator, a transformer and a point of common coupling, PCC, terminal. The transformer is between the generator and PCC terminals. The method includes: determining the generator field current; determining the output voltage, the output current and the power factor and/or angle of the output voltage and output current from the generator terminal, and determining the load angle of the generator system, output voltage from the generator terminal, output current from the generator terminal and the power factor and/or angle; and/or determining the output voltage, the output current and the power factor and/or angle of the output voltage and output current, and determining the rotor angle of the generator system, output voltage, output current from the PCC terminal and the power factor and/or angle.

Abstract: The present disclosure concerns a current limiting circuit for a power converter, which may be used to limit charge and discharge currents for electrical power storage units. In an example embodiment, a current limiting circuit comprises: first and second field effect transistors, each having source, gate and drain connections, wherein the source connection of the first transistor is connected to the gate connection of the second transistor and the source connection of the second transistor is connected to the gate connection of the first transistor; and a resistor connected between the source connections of the first and second transistors, wherein drain connections of the first and second transistors are connectable between a DC electrical power supply and an electrical load for limiting a maximum current flowing between the electrical power supply and the electrical load.

Abstract: Electrical power distribution systems and methods of operating electrical power distribution systems are provided. One electrical power distribution system comprises: an electrical power storage unit; a transformer; a first bidirectional converter circuit connected between the electrical power storage unit and a first winding of the transformer; a first DC bus; a second DC bus; a second bidirectional converter circuit connected between the first DC bus and a second winding of the transformer; a third bidirectional converter circuit connected between the second DC bus and a third winding of the transformer; and a controller connected for control of the first, second and third converter circuits to distribute electrical power between the electrical power storage unit, the first DC bus and the second DC bus.

Abstract: A power system, including: a synchronous electrical generator having a rotor; and an angle computation unit configured to: determine a rotor angle in a steady state period of the synchronous electrical generator, determine a change in rotor angle in a transient period of the synchronous electrical generator, and estimate the rotor angle in the transient period based on the steady state rotor angle and the change in rotor angle.

Abstract: A two-start helical heat exchanger comprises a helical baffle extending along a length of the heat exchanger and having first and second surfaces, wherein: the first surface of the baffle is arranged to provide a first helical fluid flow path for a first fluid; and the second surface of the baffle is arranged to provide a second helical fluid flow path for a second fluid, wherein the second fluid flow path is arranged in counter-flow with the first fluid flow path and a casing within which the baffle is mounted. The baffle is arranged such that first and second fluid flow paths are in thermal contact with each other through the baffle, and in thermal contact with the casing. The heat exchanger may be incorporated into a power converter, for example to cool the power converter. The heat exchanger may be used on an aircraft.

Abstract: A power system includes a synchronous electrical generator having a rotor driven by a shaft; a permanent magnet signaling generator, coupled to the shaft; and an angle computation unit configured to calculate a rotor angle or load angle based on a voltage from the permanent magnet signaling generator and a voltage from the synchronous electrical generator.

Abstract: An operating condition monitor (100) for monitoring an operating condition of a transistor-based power converter (102), comprising: a sensing apparatus (106) configured to measure a turn-off transient energy of the power converter (102), a processor (108) in communication with the sensing apparatus (106) to receive the measurement of the turn-off transient energy, the processor being configured to: compare the measurement of the turn-off transient energy to a threshold; and issue an event signal based on the comparison to the threshold meeting a comparison criterion. A method (200, 200?) of monitoring an operating state of a transistor-based power converter is also disclosed.

Abstract: A system, method and machine-readable instructions for monitoring a power electronics device. The system involves a semiconductor device, at least one sensor and a processor. The processor is configured to monitor a junction temperature of the semiconductor device by determining from the at least one sensor an on-state resistance of the semiconductor device and calculating the junction temperature of the semiconductor device according to a relationship between the on-state resistance of the semiconductor device and the junction temperature of the semiconductor device. The processor may apply an ageing coefficient to the on-state resistance.

Abstract: A power system, including: a synchronous electrical generator having a rotor; and an angle computation unit configured to: determine a rotor angle in a steady state period of the synchronous electrical generator, determine a change in rotor angle in a transient period of the synchronous electrical generator, and estimate the rotor angle in the transient period based on the steady state rotor angle and the change in rotor angle.

Abstract: A power system includes a synchronous electrical generator having a rotor driven by a shaft; a permanent magnet signaling generator, coupled to the shaft; and an angle computation unit configured to calculate a rotor angle or load angle based on a voltage from the permanent magnet signaling generator and a voltage from the synchronous electrical generator.

Abstract: A method determines a generator system load and/or rotor angle. The generator system has a generator with a generator terminal outputting electrical power generated by the generator, a transformer and a point of common coupling, PCC, terminal. The transformer is between the generator and PCC terminals. The method includes: determining the generator field current; determining the output voltage, the output current and the power factor and/or angle of the output voltage and output current from the generator terminal, and determining the load angle of the generator system, output voltage from the generator terminal, output current from the generator terminal and the power factor and/or angle; and/or determining the output voltage, the output current and the power factor and/or angle of the output voltage and output current, and determining the rotor angle of the generator system, output voltage, output current from the PCC terminal and the power factor and/or angle.