摘要:
A voltage mode control method and apparatus for extending speed range operation from a sinusoidally excited permanent magnet motor is described. The method includes a determination of a maximum value from a first set of parameters with each parameter having a known maximum value as well as a reading of a second set of parameters. A computation of a first derived angle using the first set of parameters and the second set of parameters is then performed. A computation of amplitude of phase voltage and a second derived angle using the first derived angle follows. A resultant output comprising a set of derived command voltages for controlling a power circuit is created whereby the power circuit can achieve required torque levels with lower currents for power switches.
摘要:
An exemplary embodiment of the invention is a method for torque control of a PM synchronous machine. The method includes obtaining a torque command signal and a machine speed and determining an operating mode in response to the torque command signal and the machine speed. The operating mode includes a first operating mode and a second operating mode. In the first operating mode, a stator phase voltage magnitude is computed and an angle between the stator phase voltage and a stator phase back emf is determined in response to the stator phase voltage magnitude. In the second operating mode, the stator phase voltage is set to a predetermined magnitude and the angle between the stator phase voltage and the stator phase back emf is determined in response to the predetermined magnitude.
摘要:
An electric vehicle accessory motor drive power supply system (40) that utilizes a single power supply design to provide efficient variable speed motor control to both brushless and brush-type DC motors (42,44). The power supply system includes at least one of each type of motor along with a first DC-DC converter (46) that provides operating power to the brushless motor (42) and a second DC-DC converter (48) that provides operating power to the brush-type motor (44). Both converters (46,48) have a power input (52) connected to the electric vehicle's high voltage bus (50) and each includes a data input (54) for receiving a speed control signal (SC) indicative of desired motor speed, as well as an output (56) for providing a motor drive signal to its associated DC motor (42,44). Each of the converters (46,48) is operable in response to its received speed control signal to convert operating power from the high voltage bus (50) into a lower voltage variable motor drive signal that is provided to its associated motor (42,44) via its output (56). The variable drive signal can be either a variable DC voltage signal or a pulse-width modulated signal. With this arrangement, a single converter design, including a single speed control interface, can be utilized to operate both brush-type and brushless motors. Furthermore, the system permits more efficient operation of the brushless motors since it obviates the need for speed control electronics on the motor itself and therefore eliminates the relatively inefficient use of cascaded PWM stages.
摘要:
An apparatus for controlling the load dump voltage of a permanent magnet (PM) alternator having a silicon controlled rectifier (SCR) bridge. The apparatus includes a voltage divider, a peak detector, and a comparator. The voltage divider attenuates the bridge output voltage, which is further fed through a peak detector to hold the peak value for improved stability. The comparator changes states when the bridge output exceeds a predetermined voltage level (e.g., 55 volts) that is less than the load dump threshold limit (e.g., 60 volts), but greater than the normal operating voltage (e.g., 42 volts). The comparator output change-in-state deactivates a gate pulse generator, thereby suppressing further operation of the SCR bridge. Voltage transients that may otherwise occur at the bridge output for the remainder portion of a half cycle from the PM alternator are clamped using a varistor or zener diode.
摘要:
A three region control strategy for a permanent magnet motor is presented. In a first control region, the permanent magnet motor is operated at, a 120° conduction square wave mode at reduced phase current, and below a no-load speed. The motor phase current commutation causes eddy current losses in the rotor magnets and core which are insignificant due to the low phase currents and relatively low rotor speed. Meanwhile, the inverter switching losses are kept low as two switches are in use (on/off) for each current commutation during the 120° conduction mode. In a second control region, the permanent magnet motor is operated at a 180° conduction sinusoidal wave mode with high phase currents. The 180° conduction sinusoidal wave mode minimizes the commutation loss. In a third control region, the permanent magnet motor is operated above its no-load speed or in a field weakening mode. At these higher speeds the slot ripple and commutation losses on the rotor increase, and the demagnetizing component of the armature reaction increases due to field weakening. Commutation losses are minimized through sinusoidal current operation. In the field weakening mode, the phase current conduction angle is set to 180° and the phase currents become sinusoidal.
摘要:
A torque sensing apparatus for picking up a magnetic field of a magnetostrictive material disposed on a shaft, the torque sensing apparatus having: a first integrating ring; a second integrating ring; a first fluxgate return strip and a second fluxgate return strip each being connected to the first integrating ring at one end and the second integrating ring at the other end; an excitation coil; and a feedback coil; wherein the first integrating ring and the second integrating ring are configured to be positioned to pick up flux signals along the entire periphery of the ends of the magnetostrictive material.
摘要:
A piston damper assembly includes a piston damper and a relative position sensor. The piston damper includes a damper body and a piston rod. The piston rod is axially movable within the damper body. The relative position sensor includes an axially-extending magnetic core, an excitation coil, and a position-sensing coil. The axially-extending magnetic core is movable with the piston rod, is located outside the damper body, and has first and second protrusions extending toward the damper body. The excitation coil is wound around the first protrusion, and the position-sensing coil is wound around the second protrusion. A piston-damper dust tube subassembly includes an axially-extending piston-damper dust tube and a relative position sensor. The relative position sensor includes an axially-extending magnetic core, an excitation coil, and a position-sensing coil. The axially-extending magnetic core is attached to the dust tube and has first and second protrusions.
摘要:
A method and device for controlling the torque of a permanent magnet (PM), synchronous, alternating-current (AC) motor, wherein the motor is powered by an inverter connected to a direct-current (DC) power source, is proposed. The method includes the steps of communicating a torque command signal from a user to a microcontroller, sensing the alternating-current phase currents of the motor and communicating electrical signals representing data concerning the phase currents to the microcontroller, sensing the position of the rotor of the motor and communicating electrical signals representing data concerning the position of the rotor to the microcontroller, and utilizing the microcontroller to implement a modulation technique to generate electrical switching signals for creating electrical sinusoidal waveforms. In addition, the method also includes the step of utilizing the microcontroller to implement a vector control technique to generate electrical control signals for adjusting the frequency and magnitude of the sinusoidal waveforms according to the phase current data, the rotor position data, the voltage supplied by the power source, and the torque command signal. In this particular step, generating the control signals includes the step of referring to look-up tables in an electronic memory only when operating the motor in a constant torque mode. Lastly, the method also includes the step of utilizing the microcontroller to communicate the switching signals for creating sinusoidal waveforms to the inverter. In this way, the inverter is able to generate and transmit sinusoidal waveforms, as dictated by the switching signals, to the motor for optimal torque control.
摘要:
The present invention discloses an arc fault detector including a shunt resistor deployed in a circuit being protected, an arc discriminator sensing voltages across the shunt resistor and outputting an arc detection signal when it detects current variations caused by parallel and series arc faults, a signal transformer buffering the arc detection signal and outputting a pulse, a switch transient detector detecting a voltage differential across load switches and outputting a pulsed switch transient detection signal when the voltage differential across load switches exceeds a reference value, a line interrupter such as a static relay, a switch controller including logic gates generating a trip signal based on predetermined criteria, and a manual switch for resetting the line interrupter. A second embodiment of the present invention senses voltage induced in a coil wrapped around a toroidal core to detect current variations in conductors which pass through the center of the toroidal core.
摘要:
A novel method is proposed for controlling the torque of a PM brushless motor with sinusoidal back-emfs without current sensors by computing the required input phase voltages with measured rotor position and speed and known machine parameters. These voltages are fed to the machine at an angle computed in terms of input parameters and the phase voltage with respect to their back-emfs so that phase currents are aligned with their back-emfs to exactly mimic the performance of the current mode controller.