678results about "General control strategies" patented technology

A synchronous bi-directional active power conditioning system (11) suitable for wide variable frequency systems or active loads such as adjustable speed drives which require variable voltage variable frequency power management systems is disclosed. Common power electronics building blocks (100, 200) (both hardware and software modular blocks) are presented which can be used for AC-DC, DC-AC individually or cascaded together for AC-DC-AC power conversion suitable for variable voltage and / or wide variable frequency power management systems. A common control software building block (2, 5) includes a digital control strategy / algorithm and digital phase lock loop method and apparatus which are developed and implemented in a digital environment to provide gating patterns for the switching elements (3, 6) of the common power-pass modular power electronics building blocks (100, 200).

A system for operating an electric motor is described. The system has a torque estimator to determine a load on the motor and a controller configured to generate a motor control signal. The controller continuously adjusts the motor control signal in response to the load on the motor. The motor control signal optimizes the motor's performance by controlling the rotor flux of the motor. The motor control signal can control the voltage or current and frequency applied to the motor.

A system and method are disclosed for turning off the voltage to a pump jack electric motor during predetermined periods of time to save energy. In the method, the motor's response to closed-loop control may be evaluated over several pump strokes. The periods of the pump stroke when it is feasible to turn off the motor may be identified. The consistency of the measurements over several strokes may be evaluated. The motor may be turned off during predetermined periods on subsequent pump strokes when each pump stroke shows sufficiently similar behavior to that predicted during the closed-loop control process. The system may return to the closed-loop control process after a predetermined period of time to adjust to any changes in the system.

In a rotary electric system, a rotary electric machine is provided with an armature core and star-connected multiphase windings with a neutral point wound in the armature core. Each of the star-connected multiphase windings has a predetermined winding configuration that prevents, when a zero-phase current is supplied from a direct current power source to the star-connected multiphase windings via the neutral point, a zero-phase magnetic flux created in the armature core based on the zero-phase current flowing in each phase winding of the star-connected multiphase windings from being cancelled out by a zero-phase magnetic flux created in the armature core based on the zero-phase current flowing in another one phase winding of the star-connected multiphase windings.

A permanent-magnet electrical machine is disclosed in which the rotor has a fixed back iron and movable back iron segments. When the movable back iron segments are in a first position, such as in contact with the fixed back iron, the field strength is high. When the movable back iron segments are in a second position in which the movable back iron segments are displaced away from the fixed back iron, the field strength is low. The ability to weaken the field strength causes the constant-power, speed ratio to be increased and thereby increases the utility of the motor for applications in which a wide speed range is desired. The disclosure applies to both permanent-magnet motors and generators. In an alternative embodiment, the stator ring is provided with a fixed portion and at least one movable stator segment.

According to input parameters, a controller carries out: generation of a voltage command value for each of d- and q-axes; conversion of the voltage command value for each of the d- and q-axes into a voltage command value for each of the multiphase windings; and control of a multiphase inverter based on the voltage command value for each of the multiphase windings. The controller adds, to the voltage command value for the q-axis, a first compensation voltage value for compensating torque ripples to thereby output a compensated voltage command value for the q-axis. The first compensation voltage value contains m-th harmonic components in the AC motor and varies depending on the rotational angle of the rotor, the m corresponding to the number of phase of the multiphase windings. The controller uses, as the voltage command value for the q-axis, the compensated voltage command value for the q-axis.

To reduce noise by limiting a current peak value to a predetermined value or less and by smoothing the waveforms of drive currents during the current limitation, switching control means (30) according to the present invention turns ON all of one-side drive transistors selected from the high-side drive transistors (21, 22 and 23) and the low-side drive transistors (25, 26 and 27) of power supply means (20) for a predetermined period, and turns OFF all of the other-side drive transistors for a predetermined period in response to a current control signal for the current peak value to a predetermined value or less.

When it is determined that a battery temperature is lower than a threshold value, an inverter control circuit alternately switches an operation point of an AC motor between an optimum operation point and a motor loss increase point. At the motor loss increase point, an increase in the amplitude of the motor current increases copper loss occurring in the three-phase coil of the AC motor. On the other hand, at the optimum operation point, a reduction in the amplitude of the motor current reduces copper loss. Corresponding to the cyclical increase / reduction in the copper loss, the battery is cyclically charged / discharged by the electric power corresponding to the copper loss. The change in the battery current occurred by the charge / discharge causes the internal resistance to generate heat, whereby the temperature of the battery is increased. The foregoing temperature increase operation is prohibited when the motor temperature exceeds an allowable temperature with which the operation efficiency of the AC motor is ensured.

A motor controller (4) and method for maximizing the energy savings in an AC induction motor (3) at every load wherein the motor is calibrated at two or more load points to establish a control line (6), which is then programmed into a non-volatile memory (30) of the motor controller. A DSP-based closed-loop motor controller observes the motor parameters of the motor such as firing angle / duty cycles (23), voltage (37), current (9) and phase angles to arrive at a minimum voltage necessary to operate the motor at any load along the control line. The motor controller performs closed-loop control to keep the motor running at a computed target control point, such that maximum energy savings are realized by reducing voltage through pulse width modulation.

A control system aims at converting, via a switching circuit, a direct current voltage into an alternating current voltage to be applied to multiphase windings of a multiphase rotary machine to thereby control rotation of the multiphase rotary machine. In the control system, a command voltage determiner determines a command voltage value for an alternating current voltage to be applied to the multiphase windings based on a zero crossing of a line-to-line current and a zero crossing of the amount of change in the line-to-line current. A driving unit drives the switching circuit on and off based on the determined command voltage value to thereby modulate the direct current voltage to the alternating current voltage to be applied to the multiphase windings.

A motor driving device that is low in cost and capable to control the phase of a motor with high efficiency and with accuracy. A motor driving device includes a motor driving part, a rotor position detector, a current phase detector, a voltage signal generator, and a driving signal generator. The motor driving part has a plurality of half bridge circuits in which a high potential side drive transistor and a low potential side drive transistor are connected in series to each other, and a connection point therebetween serves as a stator winding driving terminal of each phase of a motor. The rotor position detector detects a rotor position of the motor and outputting a rotor position signal. The current phase detector detects the phase of a phase current flowing in the stator winding driving terminal. The voltage signal generator controls and generates a voltage profile signal such that a first phase difference that is a difference between the phase of the phase current and the phase of the rotor position signal is kept to a predetermined electrical angle. The driving signal generator generates a PWM signal that drives the drive transistor of each phase depending on the voltage profile signal.

An integrated fan drive system for air-cooled heat exchangers. The integrated fan drive system has a high-torque, low speed permanent magnet motor having a rotatable shaft, a fan that is directly connected to the rotatable shaft, and a variable frequency drive device in electrical signal communication with the permanent magnet motor to control the rotational speed of the permanent magnet motor. The high-torque, permanent magnet motor comprises no more than two bearings in operative association with the shaft. The variable frequency drive device has a variable frequency controller that has an input for receiving AC power and an output for providing electrical signals that control the operational speed of high-torque, permanent magnet motor. The variable frequency drive device also includes a user interface in electronic data signal communication with the variable frequency controller to allow a user to input motor speed control data. Other embodiments of the invention are described herein.

The invention provides a method for controlling a slip mode variable structure of a brushless direct current motor based on a power exponential reaching law. The method comprises the following steps of S1, analyzing a mathematics model of the brushless direct current motor; S2, designing a slip mode controller; combining a power reaching law and an exponential reaching law, so as to obtain the improved reaching law-power exponential reaching law, and calculate the slip mode control rate at the current time; S3, setting a current loop and a speed loop for controlling the brushless direct current motor, wherein the current loop adopts the integral and proportional control type, and the speed loop adopts the slip mode variable structure control type using the power reaching law; S4, repeatedly updating the value of slip mode control rate i, so as to control the brushless direct current motor. The method has the advantages that the control quantity on the brushless direct current motor adopts three adjustable parameters, so that the control and adjusting are more flexible; a control strategy with high control quality, simple type and convenient implementing on the brushless direct current motor is provided.

A motor control device controls a motor using an angle data signal and a rotational speed signal output from a rotation detector detecting a rotation state of a rotating shaft of the motor. The motor control device includes a speed control unit that outputs a torque instruction signal corresponding to a difference between the rotational speed of the rotating shaft and a speed instruction using the speed instruction of the rotating shaft and the rotational speed signal, a limit value setting unit that sets a torque limit value indicating the maximum value of the torque applied to the rotating shaft, and a torque limit control unit that limits the torque of the rotating shaft driven by the torque instruction signal to the torque limit value or less.

The present invention previously sets a threshold voltage, compares the set threshold voltage with a reference voltage, and judges whether a minimal pulse width of a PWM signal is obtained. When a pulse width of one PWM signal is equal to or greater than the minimal pulse width, but each pulse width of two PWM signals is less than the minimal pulse width, a sine wave voltage corresponding to one of the two PWM signals less than the minimal pulse width is varied to a threshold voltage to detect two phase currents, and a remaining one phase current is calculated based on the two detected phase currents. After the phase current was detected by varying the threshold voltage, a level difference between an original sine wave voltage and the threshold voltage is set as a compensation voltage, and the sine wave voltage is compensated by the compensation voltage.

A voltage detection section and current detection section detect a voltage and current supplied to a motor, and the detected voltage and current are supplied to a position detection section. An angular speed output from the position detection section is supplied to a differentiator to output an angular acceleration. A fundamental wave component extraction section extracts a fundamental wave component of the angular acceleration, and the extracted fundamental wave component is supplied to an amplitude adjustment section. The output of the amplitude adjustment section is subtracted from the average current command by a subtraction section. This subtraction result, current detection value, and the rotor position from the position detection section are supplied to a current control section to carry out the current control operation so as to obtain a current command. The current command is supplied to an inverter to control the voltage and current so as to suppress the speed changing due to the load torque changing. Thus, stability is improved, and a decrease in cost is realized.

A drive system for a three phase brushless AC motor that is operative to optimize a transistor switching pattern to improve power output while allowing current measurement in all of the phases using a single sensor. This is achieved by defining a voltage demand vector where more than two states are required to meet a minimum state time requirement determined by the single sensor and calculating three or more state vectors that produce the demand vector while still allowing single current sensing.

The invention relates to a method and system for lowering torque pulsation of a switched reluctance motor by current adaptive control; the method comprises: preprocessing a deviation: subjecting the torque deviation to nonlinear conversion; solving torque estimated output and adaptive PID (proportion integration differentiation) control coefficient by using double-weight neural network; acquiring current set total current by PID control calculation, and acquiring each phase control current via current allocation; predicting current feed-forward compensation control by finite difference extended Kalman filter, and effectively inhibiting and lowering torque pulsation of the switched reluctance motor by joint action of adaptive PID control and prediction-based current feed-forward compensation control. Current, torque and rotor position sensors are connected with a signal processor, the signal processor executes modules of the method, compensated three-phase reference current is output to control a power converter of the motor via a current hysteresis controller, and torque pulsation of the switched reluctance motor is significantly and effective inhibited.

The present invention previously sets a threshold voltage, compares the set threshold voltage with a reference voltage, and judges whether a minimal pulse width of a PWM signal is obtained. When a pulse width of one PWM signal is equal to or greater than the minimal pulse width, but each pulse width of two PWM signals is less than the minimal pulse width, a sine wave voltage corresponding to one of the two PWM signals less than the minimal pulse width is varied to a threshold voltage to detect two phase currents, and a remaining one phase current is calculated based on the two detected phase currents. After the phase current was detected by varying the threshold voltage, a level difference between an original sine wave voltage and the threshold voltage is set as a compensation voltage, and the sine wave voltage is compensated by the compensation voltage.

A control system controls, based on a comparison between a waved real current to be supplied to a multiphase rotary electric machine and a hysteresis region established by a waved command signal, a switching timing of a switching element of an inverter to which a direct current voltage is applied to thereby match the waved real current with a waved request current. A determining unit determines whether a workload associated with rotation of the portion of the multiphase rotary electric machine is equal to or greater than a corresponding predetermined value. When it is determined that the workload is equal to or greater than the predetermined value, a changing unit changes the waved command signal from being set to the waved request current so as to determine the switching timing of the switching element based on a positional relation between the waved request current and the changed waved command signal.

The invention discloses a direct-current brushless motor self-adaptive inversion slip form control method based on a non-linear interference observer. The non-linear interference observer is adopted for observing and compensating unmodeled dynamic and external load interference of a direct-current brushless motor. The interference-compensated motor system is characterized in that: a self-adaptiveinversion slip form is adopted for designing a controller, the stable direct-current brushless motor system is ensured. By adopting the direct-current brushless motor self-adaptive inversion slip formcontrol method, the defect that inversion control needs accurate modeling information of a controlled object and disturbance cannot be overcome in inversion sliding-mode control are solved, system robustness is improved; the unmodeled dynamic and the external load interference of the direct-current brushless motor are observed and compensated by using the non-linear interference observer, the vibration level of the inversion slip form control is lowered, and control accuracy is improved; an adaptive law is designed for upper bound of interference observing error, the upper bound of the interference observing error is estimated, the estimation value of the upper bound of the interference observing error is taken as slip form switching gain, so that the stability of the whole direct-currentbrushless motor system is ensured.

A method of controlling a power converter (20) of a motor drive system (10)controls the power converter (20) during a first operating mode by applying a current control scheme, which sets power converter commands to control torque current flowing from the power converter (20) to the motor (30) to achieve desired motor speed; and initiates a second operating mode when power supply to the power converter (20) is interrupted. The second operating mode includes controlling negative torque current between the power converter (20) and the motor (30) so that mechanical energy from the motor (30) charges an element (58) on a power supply side of the power converter (20). The first operating mode is resumed when the input power recovers. Torque current between the power converter (20) and the motor (30) is also controlled to limit a maximum transient DC bus voltage.

A motor control device includes an energization controller that generates energization control signals of a bridge driver, an ADC that samples and converts analog feedback voltages corresponding to output voltages of the bridge driver into digital feedback signals, and a zero-crossing detector that receives the feedback signals so as to perform zero-crossing detection for determining commutation timing and PWM duty of the energization control signal. Sampling timings of the ADC are switched to one of PWM on period and PWM off period according to the PWM duty. The energization controller PWM drives lower side switches of the bridge driver, and the sampling timings of the ADC are set to the PWM off period. The ADC performs an ADC process of the feedback voltage both in the PWM on period and in the PWM off period, and the zero-crossing detector adopts one of ADC results according to the PWM duty.

Methods and systems are provided for controlling an electric machine via an inverter while compensating for one or more hardware delays. The method includes receiving a control signal, producing a first sampling signal based on the control signal, and adjusting the sampling signal to compensate for a first delay of the one or more hardware delays. The inverter is operable to produce a voltage signal based on the control signal, and the electric machine is operable to produce a current based on the voltage signal. A sampling of the current is performed based on the first sampling signal.