81 results about "Ac machine" patented technology

A low-cost sine-wave drive for a 3-phase permanent magnet synchronous AC machines (PMSM) in open-loop control is based on the measurements of two linear Hall sensors. The two Hall sensors are excited by a magnetic ring with the same pole number as the PMSM rotor magnet and sinusoidal flux distributions. The output signals of the Hall sensors are unified through a two-phase-type phase-lock-loop in order to reduce the impact of the sensor mounting non-uniformity during mass production. The peak torque and speed of motor is simply controlled by adjusting the amplitude of pulse-width-modulation carrier. Smooth torque control is achieved due to sinusoidal 3-phase currents. Such a simple sine-wave drive can be achieved with or without the assistance of a micro-controller unit (MCU). No current sensor is required for the motor phase current detection. This motor can be used in industrial applications where there is no strict requirement on torque response and constant speed control of PMSM machines.

A control system for an electric motor including an inverter for providing power to the electric motor, a controller for controlling the inverter, a first motor speed control block in the controller injecting a high frequency signal into the electric motor to determine the speed and position of the electric motor, a second motor speed control block in the controller detecting the back electromotive force to determine the speed and position of the electric motor, and a transition control block in said controller to vary operation between the first motor speed control block and the second motor speed control block.

A circuit for controlling an ac machine comprises a full bridge network of commutation switches which are connected to supply current for a corresponding voltage phase to the stator windings, a plurality of diodes, each in parallel connection to a respective one of the commutation switches, a plurality of dc source connections providing a multi-level dc bus for the full bridge network of commutation switches to produce sinusoidal voltages or PWM signals, and a controller connected for control of said dc source connections and said full bridge network of commutation switches to output substantially sinusoidal voltages to the stator windings. With the invention, the number of semiconductor switches is reduced to m+3 for a multi-level dc bus having m levels. A method of machine control is also disclosed.

A system and method for detecting a rotor fault condition in an AC induction machine is disclosed. The system includes a processor programmed to receive voltage and current data from an AC induction machine, generate a current frequency spectrum from the current data, and identify rotor-fault related harmonics in the current frequency spectrum. The processor is also programmed to calculate a fault severity indicator using the voltage and current data, identified rotor-fault related harmonics, and motor specifications, analyze the fault severity indicator to determine a possibility of rotor fault. The processor generates an alert based on the possibility of rotor fault.

A method of controlling a power converter (258) of a synchronous machine drive system (100) determines position and speed of a rotor (350) of the synchronous machine (300); regulates a current vector relative to a reference frame, having a direct-axis component and a quadrature-axis component, the regulating step selectively causing the current vector to lag a quadrature axis of the machine (300); and outputs a command signal to the power converter (258) as a function of the regulating step. According to one implementation, this process creates higher total torque and maintains supply voltage within a maximum level during a high speed range of the machine.

The machine in accordance with the present disclosure is an AC machine whose pole numbers can be switched (from pole p1 to pole p2), and whose number of series turns per phase N can be switched say from N0=Nrated to N1=N0 / 2. Furthermore, it employs an inverter so that the frequency can be changed from a low value (e.g., 5 Hz) to a high value (e.g., 200 Hz). Due to the combination of pole number and number of series turns switching / reconfiguration, a high torque at low speed (e.g., 0 rpm) and a high torque at high speed (e.g., 5,000 rpm) can be achieved, making mechanical gears obsolete. In addition, the output power of the motor can be increased at high speed in direct proportion to the speed increase.

An inverter circuit couples a DC voltage source having a primary side and a reference side to an electric motor or other AC machine having multiple electrical phases. An inverter circuit includes switches, diodes and a controller. For each of the electrical phases, a first switch couples the electrical phase to the primary side of the DC voltage source and a second switch couples the electrical phase with the reference side of the DC voltage source. For each of the first and second switches, an associated anti-parallel diode is configured to provide an electrical path when the switch associated with the diode is inactive. The controller is coupled to the switching inputs of each of the first and second switches and is configured to provide a control signal thereto, wherein the control signal provided to each switch comprises, in a low frequency mode, a first portion and a second portion, wherein the first portion comprises a first pulse width modulation scheme and the second portion comprises a second pulse width modulation scheme different from the first modulation scheme.

A system is provided for controlling two alternating current (AC) machines via a five-phase PWM inverter module. The system comprises a first control loop, a second control loop, and a current command adjustment module. The current command adjustment module operates in conjunction with the first control loop and the second control loop to continuously adjust current command signals that control the first AC machine and the second AC machine such that they share the input voltage available to them without compromising the target mechanical output power of either machine. This way, even when the phase voltage available to either one of the machines decreases, that machine outputs its target mechanical output power.

A method of controlling an AC machine that includes a stator and a rotor. The method includes observing a stability parameter that is indicative of the stability of the AC machine and dependent on a current state of the AC machine; and controlling the AC machine based on the observed stability parameter so as to promote stable operation of the AC machine. The method may include controlling the AC machine to operate as a motor or as a generator. The AC machine may be a permanent magnet synchronous machine. A controller suitable for performing the method is also disclosed.

The present invention relates to control of an alternator-starter for a hybrid electric vehicle having a disconnected high-voltage battery. A hybrid powertrain system includes an electric motor / generator unit having a multiphase asynchronous AC machine electrically connected to a multiphase bridge inverter. A high-voltage capacitor is electrically connected between positive and negative sides of a high-voltage DC power bus. High-voltage DC bus pre-charge circuits are electrically connected between gate drive bias power supplies and the multiphase bridge inverter. A low-voltage battery electrically charges the high-voltage DC link capacitor via the gate drive bias power supplies and the high-voltage DC bus pre-charge circuits when the high-voltage energy storage system is disconnected from the high-voltage DC power bus.

The invention relates to a horizontal triaxial tension and compression tester comprising an AC machine arranged on a test platform. The power output end of the AV machine is connected with a rigid load bar on which a force sensor is arranged; the rigid load bar is connected with a front piston rod; the front piston rod is also provided with a displacement sensor; the force sensor, the displacement sensor and a data acquisition board are connected with a computer; the other end of the front piston rod is connected with a sample cap after passing through a front baffle board, and the sample cap is connected with an air exit hole on the front baffle board by a plastic soft tube; the other end of a rolling bearing on a horizontal stand is also provided with a sample cap which is connected with a rear piston rod; the rear piston rod is connected with a fixed baffle board after passing through a rear baffle board; the AC machine is started, and then an acquisition program carries out real-time acquisition and preserves output values of the force sensor and the displacement sensor; a drain hole is opened, and then a sample is removed after water is completely discharged; and subsequently, the width of a sample tension failure zone is measured. The invention has the characteristics of good integrity, high stability of loading and high axial rigidity.

A method of controlling a power converter (258) of a synchronous machine drive system (100) determines position and speed of a rotor (350) of the synchronous machine (300); regulates a current vector relative to a reference frame, having a direct-axis component and a quadrature-axis component, the regulating step selectively causing the current vector to lag a quadrature axis of the machine (300); and outputs a command signal to the power converter (258) as a function of the regulating step. According to one implementation, this process creates higher total torque and maintains supply voltage within a maximum level during a high speed range of the machine.

Method for providing current regulation and a current controller (10) for an electric machine (30) are provided. The method includes receiving a state vector time signal (36) indicative of a time interval when a switching state vector is activated and comparing the received state vector time signal to a commanded state vector time signal (38). The method further includes using the result of the comparison to regulate a direct axis current signal (42, 44) input to an electric machine controller. The current controller (10) includes a state vector error comparator for comparing a received state vector time signal to a commanded state vector time signal and generating a state vector time error. This error is processed by a PI controller, coupled to the state vector error comparator, for providing a direct axis current signal output responsive to the state vector time error to an electric machine.

A sequentially joined segment armature coil is provided which may be employed in an ac machine such as an ac motor or motor generator. The armature coil is equipped with three phase coils each of which is made up of a first and a second phase windings identical in number of turns. This structure permits the number of turns of the armature coil to be changed easily by changing a connection of the first and second phase winding between a series connection and a parallel connection or changing a connection of the phase coils between a star connection and a delta connection. The structure also enables terminal leads of the first and second phase windings of each of the phase coils to be collected and withdrawn outside the ac machine, thus facilitating ease of arrangement of the terminal leads.

The machine in accordance with the present disclosure is an AC machine whose pole numbers can be switched (from pole p1 to pole p2), and whose number of series turns per phase N can be switched say from N0=Nrated to N1=N0 / 2. Furthermore, it employs an inverter so that the frequency can be changed from a low value (e.g., 5 Hz) to a high value (e.g., 200 Hz). Due to the combination of pole number and number of series turns switching / reconfiguration, a high torque at low speed (e.g., 0 rpm) and a high torque at high speed (e.g., 5,000 rpm) can be achieved, making mechanical gears obsolete. In addition, the output power of the motor can be increased at high speed in direct proportion to the speed increase.

The invention is an optimization method of main protection configuration of internal failure of a large-scale generator stator winding, advancing a multiloop analysis method of AC machine, considers an electric machine as a circuit network with relative movement to research its movement behavior by general circuit analysis methods, and can flexibly analyze the influence of various harmonic magnetic fields, space position and from of its winding, etc, thus solving the problem of simulation and calculation of the internal failure. On the basis of complete simulation and calculation of internal failure, the invention proposes that it should adopt a different design optimizing course according to different structures of generator winding, opens up a new way of scientifically making a solution of main protection configuration of a generator and reasonably selecting a led-out mode of neutral point-side branch and a solution of current mutual inductor configuration, corrects the previous wrong methods in the engineering, and provides a high- quality guarantee for safe operation of a large-scale generating set.

Methods and systems are provided for controlling permanent magnet machines under varying loads. The method comprises generating a d-axis voltage command and a q-axis voltage command, producing a modified d-axis current command based on the q-axis voltage command and a d-axis current command, converting the modified d-axis current command to a modified d-axis voltage command, and transmitting the modified d-axis voltage command and the q-axis voltage command to the PM machine. The d-axis voltage command is based on a d-axis current command.

The invention is a variable-frequency energy-saving control system of central air-conditioner, composed of main controller and temperature sampling controller, where the input end of the main controller is connected with 485 communication circuit, memory, analogue quantity input circuit and switching quantity input circuit, and the output end of the main controller is connected with relay output circuit and frequency inverter output control circuit; the input end of the temperature sampling controller is connected with three sampling chips and the output end of he temperature sampling controller is connected with the 485 communication interface of the main controller through 485 communication port. The main controller implements a compound control according to the temperature signal and the pressure signal of evaporator and condenser of the central air-conditioner, and controls a three-phase AC machine by the output of the frequency inverter and the relay to realize the speed change, able to realize the variable frequency switching of two frequency inverters controlling three electric machines, providing the optimum working state for variable-frequency control system and achieving the best energy-saving effect.

A stator winding is disclosed for a multiple-phase alternating current machine with several parallel winding groups (U1, V1, W1; U2, V2, W2; U3, V3, W3), each of which can be supplied with separate power sources. Locations of the winding groups can be cyclically shifted when moving from one pole to another. The number of parallel winding groups (U1, V1, W1; U2, V2 ,W2 ;U3 ,V3 , W3) can be higher than two, and the number of poles of the alternating current machine can be an even figure that is a multiple of the number of winding groups.

A method of starting a wind turbine generator of any type of polyphase AC machine, including, but not limited to, brushless DC or permanent magnet machines is disclosed. The machine starts from a dead stop or from low speed operation and is accelerated to the cut in speed for power production. The start-up is realized utilizing the common set of electrical conductors and the power converter also used for capturing the generated power. Under initial operation, the power converter executes a PWM modulation technique to drive the machine. Periodically, the PWM modulation is stopped to read the electrical position of the generator.

An electric AC machine with a primary section and a secondary section is disclosed. The primary section has a region facing the secondary section and a region facing away from the secondary section. The region facing the secondary section has windings adapted to receive an AC current. The winding of the primary section has at least one phase conductor which at least partially extends in or on the region of the primary section facing away from the secondary section, thereby producing a magnetic field that extends outside the secondary section. This arrangement can reduce overvoltages and eliminate voltage breakdowns at the star point of winding strands of a synchronous motor.

Methods and systems are provided for controlling permanent magnet machines under varying loads. The method comprises generating a d-axis voltage command and a q-axis voltage command, producing a modified d-axis current command based on the q-axis voltage command and a d-axis current command, converting the modified d-axis current command to a modified d-axis voltage command, and transmitting the modified d-axis voltage command and the q-axis voltage command to the PM machine. The d-axis voltage command is based on a d-axis current command.

A sequentially joined segment armature coil is provided which may be employed in an ac machine such as an ac motor or motor generator. The armature coil is equipped with three phase coils each of which is made up of a first and a second phase windings identical in number of turns. This structure permits the number of turns of the armature coil to be changed easily by changing a connection of the first and second phase winding between a series connection and a parallel connection or changing a connection of the phase coils between a star connection and a delta connection. The structure also enables terminal leads of the first and second phase windings of each of the phase coils to be collected and withdrawn outside the ac machine, thus facilitating ease of arrangement of the terminal leads.

The present invention provides a control system for an electric motor having a stator and rotor including an inverter for providing power to the electric motor, a controller for controlling the inverter, a low speed control block to estimate the rotor angular position using stator current components operating in the controller, a high speed control block to estimate the rotor angular position using stator current components and stator flux position operating in the controller, a transition switch in the controller to vary operation between the low speed control block and the high speed control block, and where the inverter is controlled by six step operation.

A method of controlling an AC machine that includes a stator and a rotor, wherein the method includes, whilst operating the AC machine according to an overmodulation technique: determining a reference speed for controlling the operation of the AC machine; filtering the reference speed such that if the reference speed exceeds a speed limit of the AC machine, the reference speed is reduced towards that speed limit; and controlling the operation of the AC machine based on the filtered reference speed. It has been found that controlling the AC machine in this way helps to inhibit “windup” of a controller used to implement the method, even if the overmodulation technique sets a non-constant maximum voltage.

A high phase order alternating current rotating machine is disclosed having an inverter drive that provides more than three phases of drive waveform of harmonic order H, and characterized in that the windings of the machine have a pitch of less than 180 rotational degrees. Preferably the windings are connected together in a mesh, star or delta connection. A method for operating a high phase order induction motor is also disclosed, involving electrically connecting N windings into a mesh connection with a value of Δ that provides a substantial range in speed / torque relation when operating with at least two out of first, second and third harmonic, low order harmonics being the most efficient.

A power converter configured to improve power capture in a wind turbine during low wind speed operation is disclosed. The power converter converts the power generated by the alternator of the wind turbine into a suitable AC current for delivery to a utility grid or to an electric load independent of the utility grid. The power converter is configured to operate in multiple operating modes, utilizing both synchronous and non-synchronous control methods, to extend the operating range of the power converter. During non-synchronous operation, the power converter utilizes a modulation routine that may either vary the dead-time compensation period during a constant modulation period or vary the modulation period with a constant on-time. A seamless transfer between non-synchronous and synchronous control methods with low total harmonic distortion (THD) improves the range of power generation for wind generators.

A system is provided for controlling two AC machines. The system comprises a DC input voltage source that provides a DC input voltage, a voltage boost command control module (VBCCM), a five-phase PWM inverter module coupled to the two AC machines, and a boost converter coupled to the inverter module and the DC input voltage source. The boost converter is designed to supply a new DC input voltage to the inverter module having a value that is greater than or equal to a value of the DC input voltage. The VBCCM generates a boost command signal (BCS) based on modulation indexes from the two AC machines. The BCS controls the boost converter such that the boost converter generates the new DC input voltage in response to the BCS. When the two AC machines require additional voltage that exceeds the DC input voltage required to meet a combined target mechanical power required by the two AC machines, the BCS controls the boost converter to drive the new DC input voltage generated by the boost converter to a value greater than the DC input voltage.