Abstract:
At least one example embodiment discloses a method of controlling an alternating current (ac) machine. The method includes determining or retrieving a current limit for the ac machine, determining a characterized peak current value based on a voltage-to-speed ratio of the ac machine, determining current command values for the ac machine based on at least one of the torque command limit and a torque command for the ac machine, determining current command values for the ac machine based on the torque command limit and controlling the ac machine based on the current command values.
Abstract:
In one example embodiment, a motor control unit includes a processor configured to tune a current regulator regulating a supply of electrical current to an electric motor by determining a plurality of variables, the plurality of variables including a stator resistance value, a first inductance value and a second inductance value, the stator resistance value being a resistance value of a stator of the electric motor, the first inductance value being a d-axis inductance of the electric motor and the second inductance value being a q-axis inductance of the electric motor. The processor is further configured to tune the current regulator by determining a plurality of gains based on the determined plurality of variables and generating current commands for operating the electric motor based on the determined plurality of gains.
Abstract:
For each phase of a controller, a pair of semiconductor switches comprises a high side switch and a low side switch. A direct current voltage bus provides electrical energy to the semiconductor switches at a test voltage level less than a full operational voltage level. A measuring circuit is adapted to measure the direct current bus voltage. A data processor determines that a deficiency in a tested, related semiconductor switch is present if the measured direct current bus voltage decreases or collapses upon activation of a particular semiconductor switch in the same phase of the controller, or if other sequential test results indicate a deficiency. If the deficiency in the related semiconductor switch is present the processor may prevent the voltage supply from providing the full operational voltage to the direct current data bus to prevent damage to the motor or the controller, for example.
Abstract:
A two-zone gasifier is used to produce syngas from coal fines, oxygen and steam. The two-zone gasifier has a top fluidized gasification zone and a bottom entrained flow gasification zone connected by a Venturi throat. The syngas production will occur in both zones with the syngas being collected from the top of the gasifier.
Abstract:
At least one example embodiment discloses a drive system including a motor including a rotor, the motor configured to receive a measured current, a controller configured to generate a voltage command for the motor, a sliding mode observer configured to determine an estimated current for the motor based on the voltage command, determine a difference between the measured current and the estimated current, and determine a switching control vector and an estimator configured to estimate a rotor position based on the switching control vector, the switching control vector being determined based on the difference and adaptive parameters of the sliding mode observer, the controller being further configured to control the motor based at least in part on the estimated rotor position.
Abstract:
While enforcing a fake position in the data processing system and applying a zero direct-axis current command, positive and negative quadrature-axis current commands are applied sequentially and at approximately same magnitude to urge the rotor toward an enforced position. A processing module measures a positive quadrature-axis current aligned raw position data after application of the positive quadrature-axis current command and measures negative quadrature-axis current aligned raw position data for the rotor after application of the negative quadrature-axis command. An initial position offset calibrator or data processor determines a difference between the raw position data to determine an alignment of a true averaging axis. An initial position offset calibrator or data processor determines a raw averaging axis position data based on an average of the raw position data. An initial position offset calibrator or data processor determines a position offset based on a difference between the determined true averaging axis and the determined raw averaging axis position data.
Abstract:
A data storage device stores previous position readings of the rotor for a previous cycle of a pulse width modulation signal applied to the motor. A current raw position reading for the current cycle is received. A predicted position reading for a current cycle is determined based on at least one of the stored previous position readings of the previous cycle. A data processor determines whether a difference between the current raw position reading and the predicted position reading for a first mode and a second mode is within one or more preset thresholds. The data processor selects the current raw position reading as a verified reliable final position reading if a first difference for the first mode is equal to or less than a primary preset threshold or if a second difference for the second mode is equal to or less than a secondary preset threshold.
Abstract:
The invention provides a yeast strain and a method for making the same. The method has the step of replacing the regulation region upstream of the hsp104 gene in the genome of the yeast, so as to accelerate and prolong the expression span of hsp104 gene and enhance the capability of the yeast to ferment and produce ethanol in a high-temperature environment. The yeast is capable of fermenting glucose at a temperature higher than 42° C. to produce ethanol, or biomass ethanol, wherein the ethanol production ratio based on fermentation of glucose is higher than 97%. Being able to synchronize the degradation/hydrolysis stage and fermentation stage of biomass ethanol producing process, the yeast in accordance with the present invention is able to lower the production cost of biomass ethanol and further raise the productivity with its high ethanol production ratio.
Abstract:
A sliding module includes a first section, a second section, a sliding member, a rotary plate, and at least one elastic member. The sliding member is slidably engaged with the second section, and is rotatably connected to the first section. The rotary plate is respectively rotatably connected to the first section and the second section. One end of the at least one elastic member is fixed to the second section, and the other end is fixed to the sliding member. When the sliding member slides relative to the second section, the rotary plate rotates relative to the second section and causes the first section to move and rotate relative to the second section in a tilted orientation.
Abstract:
A temperature estimation module estimates a change in temperature of the magnets associated with the rotor of the motor based on an operational magnetic flux strength that is compared to a reference magnetic flux strength determined at a known ambient temperature and for a predetermined operating range of the motor The temperature estimation module or the system establishes a relationship between the estimated change in the temperature and a magnetic torque component of a target output torque of the motor consistent with the predetermined operating range. The current adjustment module or the system adjusts a command (e.g., quadrature-axis current command) for the motor to compensate for shaft torque variation associated with the estimated change in the temperature in conformance with the established relationship.