Abstract:
Systems and methods are disclosed for reducing engine fuel consumption during regenerative braking. According to certain embodiments, the regenerative braking system has an engine, a generator, a rectifier, a first inverter, a traction motor, and a reverse recovery unit. The generator is configured to be driven by the engine to produce AC electrical power. The rectifier is configured to receive AC electrical power from the generator and convert the AC power to DC power. The first inverter is configured to receive the DC power and convert the DC power to AC power. The traction motor is configured to be driven by the AC power in a traction mode, and to produce regenerated power when rotated in reverse in a regenerative braking mode. The reverse recovery unit has a second inverter and a filter. The second inverter is electrically connected in parallel with the rectifier and configured to communicate at least part of the regenerated power from the traction motor to the generator during the regenerative braking mode. The filter is electrically connected downstream of the second inverter and in parallel with the rectifier. The filter is configured to filter transient voltage generated by the second inverter during the regenerative braking mode.
Abstract:
A hybrid power train system for a tractor scraper is provided. The hybrid power train system may include a primary power source coupled to a first set of traction devices, a generator coupled to the primary power source, a first electric motor coupled to a second set of traction devices, an inverter circuit coupled to the generator and the first electric motor, an energy storage device coupled to the inverter circuit, and a controller operatively coupled to the inverter circuit. The controller may be configured to engage a first operation mode enabling electrical energy, supplied by the generator and the first electric motor, to be stored in the energy storage device, and engage a second operation mode enabling electrical energy, stored in the energy storage device, to be supplied to the first electric motor to drive the second set of traction devices.
Abstract:
A ground fault detection system may include a direct current (DC) voltage source and an alternating current (AC) device. The ground fault detection system may also include an inverter, coupled to the DC voltage source, the AC device and an electrical ground, including: a positive rail, a negative rail and a plurality of switch elements, wherein each of the plurality of switch elements may be coupled to the positive rail, the negative rail and the AC device. The ground fault detection system may further include a voltage monitoring device coupled to the positive rail, the negative rail and the electrical ground and an electronic controller, coupled to the inverter and the voltage monitoring device configured to: control the plurality of switching elements, sample a voltage potential across the voltage monitoring device at predetermined time periods and determine a ground fault of the inverter based at least in part on the sampled voltage potential and the predetermined time periods.
Abstract:
A hybrid power train system for a tractor scraper is provided. The hybrid power train system may include a primary power source coupled to a first set of traction devices, a generator coupled to the primary power source, a first electric motor coupled to a second set of traction devices, an inverter circuit coupled to the generator and the first electric motor, an energy storage device coupled to the inverter circuit, and a controller operatively coupled to the inverter circuit. The controller may be configured to engage a first operation mode enabling electrical energy, supplied by the generator and the first electric motor, to be stored in the energy storage device, and engage a second operation mode enabling electrical energy, stored in the energy storage device, to be supplied to the first electric motor to drive the second set of traction devices.
Abstract:
Systems and methods are disclosed for controlling a torque output by an AC motor drawing power from a DC bus. According to certain embodiments, the system for controlling the torque output has a controller and an inverter. The controller further has an operation status detector, a basic voltage vector calculator, and a voltage command generator. The operation status detector is configured to determine a DC bus voltage and a rotor field vector. The basic voltage vector calculator is configured to calculate a plurality of basic voltage vectors having a magnitude proportional to the DC bus voltage. The voltage command generator is configured to generate a voltage command for producing a stator field vector. Producing the stator field vector includes at least one of maintaining a constant angle between the stator field vector and the rotor field vector, and setting a magnitude of the stator field vector equal to the magnitude of the plurality of basic voltage vectors. The inverter is electrically connected to the controller and configured to receive the voltage command. The inverter is also configured to convert the DC bus voltage to one or more AC voltage signals according to the voltage command. The inverter is further configured to apply the one or more AC voltage signals to the AC motor to produce the stator field vector.
Abstract:
A system for determining an initial rotor position of an interior permanent magnet (IPM) machine having a rotor and a stator is provided. The system may include a drive circuit in operative and electrical communication with each phase of the IPM machine, and a controller in electrical communication with the drive circuit. The controller may be configured to engage the drive circuit to selectively apply a voltage signal to each phase of the stator of the IPM machine, detect a current signal through each phase corresponding to the applied voltage signal, and calculate the initial rotor position based on a least squares analysis between at least the voltage signal, the current signal and a predefined inductance of the IPM machine.
Abstract:
A system for determining an initial rotor position of an interior permanent magnet (IPM) machine having a rotor and a stator is provided. The system may include a drive circuit in operative and electrical communication with each phase of the IPM machine, and a controller in electrical communication with the drive circuit. The controller may be configured to engage the drive circuit to selectively apply a voltage signal to each phase of the stator of the IPM machine, detect a current signal through each phase corresponding to the applied voltage signal, and calculate the initial rotor position based on a least squares analysis between at least the voltage signal, the current signal and a predefined inductance of the IPM machine.
Abstract:
The present disclosure is related to a method for regenerative braking of a machine. The machine includes an electric drive assembly. The electric drive assembly includes a generator, a motor and a direct current bus and a regenerative brake assembly disposed between them. The regenerative braking assembly includes an inverter. The method includes connecting a phase leg between the direct current bus and the inverter. The phase leg includes an inductor and an electric switch. The phase leg boosts the regenerative voltage. The boosted regenerative voltage is then fed back to control a braking torque from the motor and directed back to the generator.
Abstract:
A control system for an alternating current (AC) machine having a rotor and a stator is disclosed. The control system may include a direct current (DC) link providing a variable DC link voltage; an inverter module operatively coupled between the DC link and the AC machine, and a controller in communication with the inverter module. The inverter module may include a plurality of gates in selective communication with each phase of the stator. The controller may be configured to receive a signal indicative of the variable DC link voltage, receive a signal indicative of a rotational speed of the rotor, receive a torque command, and generate a direct-axis current command and a quadrature-axis current command using the variable DC link voltage, the rotational speed, and the torque command as inputs into a three-dimensional lookup table preprogrammed into a memory associated with the controller.
Abstract:
The present disclosure is related to a method for energy management for an electric drive system during regenerative braking of a machine. The machine includes an electric drive assembly. The electric drive assembly includes a generator, a motor, a primary direct current bus and a secondary direct current bus having a regenerative brake assembly. The method of energy management includes connecting at least a chopper and a crowbar across the secondary direct current bus. Further, the method includes directing a secondary power stored during regenerative braking, from the primary or secondary or both the buses through the chopper or the crowbar during fault condition.