Abstract: A downhole system includes a drill string having a drilling fluid flow channel and at least one turbine alternator deployed in the flow channel. The turbine alternator is configured to convert flowing drilling fluid to electrical power. A voltage bus is configured to receive electrical power from the turbine alternator and at least one electrical motor is configured to receive electrical power from the voltage bus. An electronic controller is configured to provide active control of the turbine alternator via processing a desired speed of the electrical motor to generate a desired torque current and feeding the desired torque current forward to the turbine alternator. The turbine alternator is responsive to the desired torque current such that it modifies the electrical power provided to the voltage bus in response to the desired torque.

Abstract: A downhole system includes a drill string having a drilling fluid flow channel and at least one turbine alternator deployed in the flow channel. The turbine alternator is configured to convert flowing drilling fluid to electrical power. A voltage bus is configured to receive electrical power from the turbine alternator and at least one electrical motor is configured to receive electrical power from the voltage bus. An electronic controller is configured to provide active control of the turbine alternator via processing a desired speed of the electrical motor to generate a desired torque current and feeding the desired torque current forward to the turbine alternator. The turbine alternator is responsive to the desired torque current such that it modifies the electrical power provided to the voltage bus in response to the desired torque.

Abstract: A downhole system includes a drill string having a drilling fluid flow channel and at least one turbine alternator deployed in the flow channel. The turbine alternator is configured to convert flowing drilling fluid to electrical power. A voltage bus is configured to receive electrical power from the turbine alternator and at least one electrical motor is configured to receive electrical power from the voltage bus. An electronic controller is configured to provide active control of the turbine alternator via processing a desired speed of the electrical motor to generate a desired torque current and feeding the desired torque current forward to the turbine alternator. The turbine alternator is responsive to the desired torque current such that it modifies the electrical power provided to the voltage bus in response to the desired torque.

Abstract: A fault tolerant inverter or controlled rectifier system includes a first leg having at least one switch device, a spare leg having at least one spare switch device, a spare leg connect switch associated with the spare leg and the first leg, a fault detection sub-system for detecting a fault in the first leg and outputting a signal on detection of a fault in the first leg, and a leg selection control sub-system that receives the signal output by the fault detection sub-system and controls the operation of the spare leg connect switch in accordance with the output signal, such that on detection of a fault the spare leg may be activated to take over the operation of the first leg.

Abstract: A fault tolerant inverter or controlled rectifier system includes a first leg having at least one switch device, a spare leg having at least one spare switch device, a spare leg connect switch associated with the spare leg and the first leg, a fault detection sub-system for detecting a fault in the first leg and outputting a signal on detection of a fault in the first leg, and a leg selection control sub-system that receives the signal output by the fault detection sub-system and controls the operation of the spare leg connect switch in accordance with the output signal, such that on detection of a fault the spare leg may be activated to take over the operation of the first leg.

Abstract: A downhole generator system including a controlled rectifier for receiving electrical power from a generator and outputting rectified electrical power. A control system controls the operation of the controlled rectifier and a chopper circuit connected to the output of the controlled rectifier connects a load selectively across the output of the controlled rectifier to regulate the output of the generator system. The control system controls the chopper circuit and/or the controlled rectifier based at least in part on a feed-back signal representative of an electric current output by the generator system and an electric current passing through the chopper circuit.

Abstract: A downhole system includes a drill string having a drilling fluid flow channel and at least one turbine alternator deployed in the flow channel. The turbine alternator is configured to convert flowing drilling fluid to electrical power. A voltage bus is configured to receive electrical power from the turbine alternator and at least one electrical motor is configured to receive electrical power from the voltage bus. An electronic controller is configured to provide active control of the turbine alternator via processing a desired speed of the electrical motor to generate a desired torque current and feeding the desired torque current forward to the turbine alternator. The turbine alternator is responsive to the desired torque current such that it modifies the electrical power provided to the voltage bus in response to the desired torque.

Abstract: An electric machine includes a rotor having at least one pole pair, the at least one pole pair including a first magnetic pole and a second magnetic pole having opposite polarities. The first magnetic pole may include a first inner radial permanent-magnet layer and a first outer radial permanent-magnet layer. The second magnetic pole may include a second inner radial permanent-magnet layer and a second outer radial permanent-magnet layer. An outer end of the first inner radial permanent-magnet layer and an outer end of the second inner radial permanent-magnet layer may be separated by an angle of between about 27 and about 55 electrical degrees. The electric machine may also include a stator having a stator core with an odd number of stator slots per pole pair of the rotor.

Abstract: An electric machine includes a rotor having at least one pole pair, the at least one pole pair including a first magnetic pole and a second magnetic pole having opposite polarities. The first magnetic pole may include a first inner radial permanent-magnet layer and a first outer radial permanent-magnet layer. The second magnetic pole may include a second inner radial permanent-magnet layer and a second outer radial permanent-magnet layer. An outer end of the first inner radial permanent-magnet layer and an outer end of the second inner radial permanent-magnet layer may be separated by an angle of between about 27 and about 55 electrical degrees. The electric machine may also include a stator having a stator core with an odd number of stator slots per pole pair of the rotor.

Abstract: A predictive load management system includes a power source operable to generate power output, the power source having a desired operating range. A transmission having a drive member is operably engaged with the power source. A control system is in communication with the power source and the transmission. The control system receives at least one input indicative of a load on the transmission and identifies a change in the load on the transmission based on the at least one input. The control system is further operable to determine a desired power output of the power source to account for the change in the load on the transmission. The control system modifies a performance characteristic of the power source to cause the power source to generate the desired power output when the change in the load on the transmission will result in the power source operating outside of the desired operating range.