2249 results about "AC motor" patented technology

An apparatus for controlling the speed of an AC motor comprising a switch adapted to be coupled in parallel with power terminals for the AC motor; a capacitor coupled in series with the parallel combination of the switch and the motor; the capacitor adapted to provide an AC supply voltage from an AC source to the parallel circuit comprising the motor and the switch; and a control circuit for controlling the conduction time of the switch in order to vary the speed of the motor. The switch is preferably pulse-width modulated at a frequency twice the line frequency of the AC supply voltage, and the switch is turned on when the voltage across the AC motor is zero volts. The apparatus is operable to provide for continuously variable control of the motor speed while minimizing acoustic noise in the motor.

A power system for an electric motor drive such as may be used in an electrically propelled vehicle incorporates the combination of a high power density battery and a high energy density battery to provide an optimal combination of high energy and high power, i.e., a hybrid battery system. The hybrid battery system in one form includes components which prevent electrical recharge energy from being applied to the high energy density battery while capturing regenerative energy in the high power density battery so as to increase an electric vehicle's range for a given amount of stored energy. A dynamic retarding function for absorbing electrical regenerative energy is used during significant vehicle deceleration and while holding speed on down-hill grades, to minimize mechanical brake wear and limit excessive voltage on the battery and power electronic control devices. The high energy density battery coupled in circuit with a boost converter, a high power density battery, a dynamic retarder, and an AC motor drive circuit. The hybrid battery system is controlled by a hybrid power source controller which receives signals from a vehicle system controller using current and voltage sensors to provide feedback parameters for the closed-loop hybrid battery control functions.

A power system for use in hydraulic fracturing or fracking of wells is disclosed. The power system is generally self-contained on a transportable system, such as a trailer. The weight and configuration of the trailer must be sized to be hauled legally on United States roadways. The system components include a turbine generator, rectifier, inverter units and AC motors.

A method and apparatus are implemented in software to control motor speed as a function of available power in a DC source—inverter—AC motor system, i.e. to perform maximum power tracking of motor speed. An inverter or motor drive converts DC power from a DC source, such as a solar panel, to AC power, to power the motor. The inverter or motor drive is controlled by software, implemented either by programmable features built directly into the inverter or drive or by a separate programmable device connected to the inverter or drive, to track motor power as a function of source power. The software-controlled inverter or drive sets motor speed as a function of source power by sensing only a single parameter, the DC source voltage. The software-controlled inverter or drive samples the source voltage at preset intervals, and changes the frequency of the AC output of the inverter or drive to match or track the available power so that the motor operates at or near its optimum for any source voltage.

A method and apparatus control a power converter (20) of an AC motor drive system (10). The method and apparatus: generate a field current regulating signal to control a field current component flowing from the power converter (20) to the AC motor (30), thereby achieving field current regulation; generate a torque current regulating signal to control a torque current component flowing from the power converter (20) to the AC motor (30), thereby achieving torque current regulation, the torque current regulation having lower priority than the field current regulation; and execute a close-loop field weakening control scheme, which generates a field weakening control command as a function of the difference between a torque current regulation voltage demand and voltage available for torque current regulation. The field current regulating signal is adjusted in accordance with the field weakening control signal to selectively reduce back EMF of the AC motor (30), thereby enabling the step of generating a toque current regulating signal to achieve a toque current component needed to drive the AC motor (30) at a desired speed despite a limitation on DC voltage available to the power converter (20).

A controller for an AC electric motor, includes a Feed Forward Torque Controller and a load model. The Torque controller directly derives a torque related component of applied motor voltages from a signal representing a torque command input T* and at least one motor parameter. The load model derives a motor speed value including a model of motor speed behaviour of the AC electric motor to provide an output signal which represents the motor speed of the AC electric motor. This motor speed output signal is used in determining a frequency of rotation of an applied motor voltage vector. Where an input to the load model is the signal representing the torque command input T*, the load model uses the signal representing the torque command T*, at least over a part of an operating speed range of the AC motor which includes zero speed, to determine the motor speed output signal.

The invention includes a programmable emergency-stop circuit apparatus and method that provides advanced function not found in other systems. The circuit centralizes the control of high voltage motor power into one place, by providing connections for, in its minimum configuration, several different kill switches, a motors-on button, and an AC motor power relay coil. In the present invention, kill switches, test inputs, emergency-stop and motors-on buttons, computer ready and watchdog signals are all conveniently connected in one location, alongside the AC motor power relay coil driver. Programmable options exist for testing kill inputs online, while the emergency stop is energized.

The invention relates to a single phase ac motor over current protector in the field of compression refrigerating machine motor protector. It comprises a casing, a cover, an electric-heat wire, a double mental sheet, a fist hook, a second hook, a moving contact, a static contact, a fixed base and a trigger mechanism, wherein the static contact is fixed on the first hook; the electric-heat wire is fixed positioned inside the electric-heat wire channel by a pair of first and second column; the second column is connected with the second hook; the double mental sheet is disk type and positioned on the double mental sheet base upper to the electric-heat wire; the trigger mechanism comprises a top rod and a spring sheet; the top rod is positioned in the top rod hole of the fixed base; the top end and the low end of the double mental sheet are corresponding with the spring sheet; the fixed end of the spring sheet is fixed on spring sheet fixed base which is the lower part of the fixed base; the free end extents to the contact space-limit which is the channel lower part of the fixed base; the moving contact is fixed on the free end and is corresponding with the static contact.

The invention provides a power-dissipation-free and energy-saving type start protector of a single phase AC motor and belongs to the technical field of refrigeration compressors. The power-dissipation-free and energy-saving type start protector comprises a shell, a shell cover, an overload protector, a power-dissipation-free starter and an external terminal mechanism. The shell is provided with an overload protector seat, a power-dissipation-free starter accommodation cavity, an external terminal mechanism cavity and a start controller accommodation cavity. The shell cover is provided with a first three-terminal jack and a second three-terminal jack. The overload protector is arranged in an overload protector accommodation cavity. The power-dissipation-free starter comprises a power-dissipation-free starter body and a start controller. The external terminal mechanism is matched with the external terminal mechanism cavity. The start protector is characterized in that the external terminal mechanism cavity comprises a first insertion cavity, a second insertion cavity and a third insertion cavity, the second insertion cavity is formed in the left side of the shell, and the bottom wall of the second insertion cavity is provided with a second shell insertion groove; the first insertion cavity and the third insertion cavity are formed in the right side of the shell, a first shell insertion groove is formed in the bottom wall of the first insertion cavity, and a third shell insertion groove is formed in the bottom wall of the third insertion cavity; the external terminal mechanism comprises a first insertion piece and a second insertion piece, the first insertion piece is matched with the second shell insertion groove in an inserted mode, and the second insertion piece is matched with the first shell insertion groove in an inserted mode.

Upon detection of a fault in a DC power supply based on a voltage from a voltage sensor or a temperature from a temperature sensor, a control device controls inverters to cause AC motors to output zero output torque, and generates and outputs signals to a voltage step-up converter and a DC / DC converter, respectively. The control device generates and outputs a signal SE of an L level to system relays to cut off the system relays. Thereafter, the control device generates and outputs a signal PWMDL to the voltage step-up converter to switch control of the voltage step-up converter to voltage step-down control.

Methods and apparatus for controlling switching in a DC-to-AC inverter to prevent overvoltages applied to an AC motor by determining the switching order of the phase voltage signals, providing gating signals at switching intervals by modulating a carrier wave with the phase voltage signals, comparing the switching intervals to a predetermined minimum time interval sufficient for reflected wave transients to dissipate, and adjusting the switching intervals to be at least equal to the predetermined minimum time interval.

An inverter control apparatus includes an instruction calculator which receives a speed instruction and a particular component of a current of a motor to obtain an output frequency instruction and output voltage instructions of an inverter and a current estimator to estimate, according to a reference phase obtained by integrating a current detection value of one phase of an ac motor and an output frequency instruction thereof, currents of other phases of the ac motor. The current estimator includes a uvw / dq converter which converts a fixed coordinate system into a rotating coordinate system, a dq / uvw converter which is connected to the uvw / dq converter and which converts the rotating coordinate system into the fixed coordinate system, and a closed loop to input an output from the dq / uvw converter to the uvw / dq converter. This system can therefore estimate currents of other phases according to the motor current of one phase.

A hybrid propulsion system for powering vehicles such as class 8 DOT classified semi-tractor trucks under normal load conditions and at highway speeds comprises an internal combustion engine, an AC generator powered by the engine, DC battery packs, an AC / DC controller, and an AC electric motor driving the drive train of the vehicle. The AC generator and the DC battery packs provide input to the AC / DC controller, which, in turn, converts the DC input from the DC battery packs via a DC circuit to AC so that the output from the AC / DC controller to the electric motor is AC for powering the vehicle. The DC battery packs may comprise thin plate flooded lead acid cells and may be connected in series, in parallel or a combination thereof. Vehicles may be retrofitted to incorporate the propulsion system.

Upon detection of a fault in a DC power supply based on a voltage from a voltage sensor or a temperature from a temperature sensor, a control device controls inverters to cause AC motors to output zero output torque, and generates and outputs signals STP1, STP2 to a voltage step-up converter and a DC / DC converter, respectively. The control device generates and outputs a signal SE of an L level to system relays to cut off the system relays. Thereafter, the control device generates and outputs a signal PWMDL to the voltage step-up converter to switch control of the voltage step-up converter to voltage step-down control.

A system and method for determining the stator winding resistance of AC motors is provided. The system includes an AC motor drive having an input connectable to an AC source and an output connectable to an input terminal of an AC motor, a pulse width modulation (PWM) converter having switches therein to control current flow and terminal voltages in the AC motor, and a control system connected to the PWM converter. The control system generates a command signal to cause the PWM converter to control an output of the AC motor drive corresponding to an input to the AC motor, selectively generates a modified command signal to cause the PWM converter to inject a DC signal into the output of the AC motor drive, and determines a stator winding resistance of the AC motor based on the DC signal of at least one of the voltage and current.

A electric motor drive apparatus comprising a voltage control unit performing voltage control processing that determines alternating-current voltage command values serving as command values of the alternating-current voltages to be supplied to the alternating-current electric motor and generates switching control signals for the inverter; and a control mode selection unit selecting a synchronous control mode in which a cycle of electric angle of the alternating-current electric motor is synchronized with a switching cycle of the inverter, or an asynchronous control mode in which the cycles are not synchronized with each other. Current detection processing is performed to detect currents flowing in coils of the alternating-current electric motor in every standard calculation cycle that is set to a half of a cycle of the carrier.

A boost converter boosts a DC voltage of a DC power supply. An inverter converts the output voltage of the boost converter into an AC voltage. An AC motor is driven by the output voltage of the inverter. A control device which controls the boost converter reduces an output voltage instruction value of the boost converter in the case where the rotation speed of the AC motor is decreased and an absolute value of a variation rate of the rotation speed is not less than a predetermined value. The inverter is controlled in the control mode selected from a plurality of control modes including three modes of a sine wave PWM control mode, an overmodulation PWM control mode and a rectangular wave control mode. The control device of the boost converter reduces the output voltage instruction value of the boost converter only in the case where the control mode of the inverter is the rectangular wave control mode or the overmodulation control mode.

A system and method for measuring and controlling stator winding temperature in an AC motor while idling is disclosed. The system includes a circuit having an input connectable to an AC source and an output connectable to an input terminal of a multi-phase AC motor. The circuit further includes a plurality of switching devices to control current flow and terminal voltages in the multi-phase AC motor and a controller connected to the circuit. The controller is configured to activate the plurality of switching devices to create a DC signal in an output of the motor control device corresponding to an input to the multi-phase AC motor, determine or estimate a stator winding resistance of the multi-phase AC motor based on the DC signal, and estimate a stator temperature from the stator winding resistance. Temperature can then be controlled and regulated by DC injection into the stator windings.

In a drive system of an AC motor in which a motor current is feedback-controlled, a motor current command is produced in a normal operation according to a torque command value on an optimum efficiency characteristic line so as to select an optimum current phase maximizing an output torque with a constant motor current amplitude. Conversely, when the AC motor produces an excessively generated power exceeding a regeneratable power quantity of the AC motor, a consuming operation is performed for intentionally increasing the power loss in the AC motor. In the consuming operation, the motor current command is produced according to the torque command value on a loss increase characteristic line to change the current phase from the above optimum value. Thereby, the power loss in the AC motor can be increased to consume the surplus power without causing instability in the motor control.

A toroidal motor having a generally circular rotor surrounded by an annular stator is disclosed. The rotor has a plurality of poles disposed about a circumference thereof. A shaft extends axially away from the poles and is attached to the rotor. The stator is generally annular and includes an annular winding surrounding the circumference thereof. Disposed about the winding are a plurality of stator poles. The number of stator poles is generally equal to the number of rotor poles. When the winding and hence the stator is excited, a magnetic field is produced between the stator and rotor poles that creates torque upon the shaft.

An automatic 4-roller barrel shaping unit for the production line of three-element cleaner used to treat the tail gas of car is composed of machine frame, feeding track with both side barrier plates, feeding manipulator with its guide track and cylinder, blanking cylinder with push plate, the upper, lower, front and back rollers, AC motor and speed reducer. Its advantages are high automation level and productivity, and simple structure.

A synchronous AC motor has a stator with stator poles arranged as a plurality of circumferentially extending stator pole groups, with each stator pole group having a pair of corresponding circumferentially extending loop-configuration stator windings disposed adjacent on either side or a single such winding disposed adjacent at one side, adjacent stator pole groups being mutually circumferentially displaced by a fixed amount corresponding to a specific electrical phase angle. A rotating magnetic field is produced by applying respective polyphase AC voltages to the windings, such that currents of mutually opposite direction flow in each pair.

A hybrid propulsion system for powering vehicles such as class 8 DOT classified semi-tractor trucks under normal load conditions and at highway speeds comprises an internal combustion engine, an AC generator powered by the engine, DC battery packs, an AC / DC controller, and an AC electric motor driving the drive train of the vehicle. The AC generator and the DC battery packs provide input to the AC / DC controller, which, in turn, converts the DC input from the DC battery packs via a DC circuit to AC so that the output from the AC / DC controller to the electric motor is AC for powering the vehicle. The DC battery packs may comprise thin plate flooded lead acid cells and may be connected in series, in parallel or a combination thereof. Vehicles may be retrofitted to incorporate the propulsion system.

The motor, which is an incorporated N-phased motor, comprises a rotor having four or more poles with N-poles and S-poles being alternately arranged in the circumferential direction, a stator having a stator core in which magnetic circuits are magnetically separated within an electrical angle of 360°, and an (N−1) number (N is a positive integer) of windings. The motor is configured so that currents of the windings can effectively work on the magnetic circuits.

In a drive system of an AC motor in which a motor current is feedback-controlled, a motor current command is produced in a normal operation according to a torque command value on an optimum efficiency characteristic line so as to select an optimum current phase maximizing an output torque with a constant motor current amplitude. Conversely, when the AC motor produces an excessively generated power exceeding a regeneratable power quantity of the AC motor, a consuming operation is performed for intentionally increasing the power loss in the AC motor. In the consuming operation, the motor current command is produced according to the torque command value on a loss increase characteristic line to change the current phase from the above optimum value. Thereby, the power loss in the AC motor can be increased to consume the surplus power without causing instability in the motor control.

An electric motor control system including a generator, an AC motor, a power converter for driving the AC motor using a DC output voltage of the generator, and an electric motor controller for controlling the power converter. The electric motor controller controls the power converter by predicting a change in the DC voltage.

A training apparatus including a training element for a user performing exercises, an AC motor and a frequency converter being arranged to control the AC motor, wherein the frequency converter comprises measuring means being arranged to measure a voltage and a current of the AC motor and calculation means being arranged to calculate a magnetic state of the AC motor using the measured voltage, the measured current, a reference torque and a reference flux in order to generate a torque of the AC motor. The training apparatus further comprises a control unit having a machine control module being arranged to calculate the reference flux and the reference torque using an intended overall torque, wherein the machine control module is connected to the frequency converter and arranged to transmit the reference flux and the reference torque to the frequency converter.