33 results about "Hysteresis band" patented technology

A data processor establishes a first range of rotational speeds of a rotor of the motor from a first lower limit to a first higher limit and a second range of rotational speeds from a second lower limit to a second higher limit. A hysteresis band or a rotational range of speeds is established such that during operation in the first range the first higher limit is adjusted (e.g., raised by a first amount to be greater than the second lower limit). A sensor detects or measures a rotational speed of a rotor of the motor. The data processor determines whether the measured rotational speed falls within the first range or the second range, as adjusted by the hysteresis band, to identify a selected speed range. A switching frequency of a pulse-width modulation signal is varied in accordance with the selected speed range.

A data processor establishes a first range of rotational speeds of a rotor of the motor from a first lower limit to a first higher limit and a second range of rotational speeds from a second lower limit to a second higher limit. A hysteresis band or a rotational range of speeds is established such that during operation in the first range the first higher limit is adjusted (e.g., raised by a first amount to be greater than the second lower limit). A sensor detects or measures a rotational speed of a rotor of the motor. The data processor determines whether the measured rotational speed falls within the first range or the second range, as adjusted by the hysteresis band, to identify a selected speed range. A switching frequency of a pulse-width modulation signal is varied in accordance with the selected speed range.

The invention discloses a method for controlling a power supply of an electron-optical circuit system of an electron beam furnace and a power supply device. The method takes the extraction value of an acceleration voltage sampling signal of a power supply of an electron beam generating system as a control signal for a focusing and deflection scanning power supply and the amplitude of a focusing and deflection scanning current changes linearly according to the control signal, which ensures that the operation parameter of the electron-optical circuit system is free from the influence of the fluctuation of the acceleration voltage. The power supply device has the acceleration voltage sampling signal connected with a square root extractor first and then connected to a focusing and deflection scanning power supply control circuit, and adopts a hysteresis-band current tracking pulse modulation controller to maintain a small up and down oscillation amplitude of a working current based on an expected value. An extraction value signal of the acceleration voltage sampling signal is used to control a focusing current, and a general control signal which is the produce of a deflection scanning integrated signal and the extraction value of the acceleration voltage sampling signal is used to control deflection scanning current, so the focusing and deflection scanning region of the electron beam is not influenced by the acceleration voltage, and in event of failure, the change of the focusing and deflection scanning region of the electron beam is controlled in a permitted range.

A system and method for counting ridges in a captured print image frame is described. A pixel path through the captured print image frame is traversed. A hysteresis band for the pixel path is determined. A number of crossings of the determined hysteresis band is counted while traversing the pixel path. A number of print ridges based on the counted number of hysteresis band crossings is determined.

A weight-based occupant characterization method reliably distinguishes between large and small adult occupants by dynamically adjusting a threshold used to distinguish between large and small adult occupants. The threshold adjustments effectively increase the separation between the detected weight and the threshold, minimizing oscillation of the determined characterization following an initial occupant characterization. A learning routine gradually adjusts the threshold up to a predefined maximum adjustment so long as the detected weight is within a tolerance or hysteresis band, or a locking routine produces a step change adjustment of the threshold when the detected weight is outside the tolerance or hysteresis band for at least a predefined time.

A weight-based occupant characterization method reliably distinguishes between large and small adult occupants by dynamically adjusting a threshold used to distinguish between large and small adult occupants. The threshold adjustments effectively increase the separation between the detected weight and the threshold, minimizing oscillation of the determined characterization following an initial occupant characterization. A learning routine gradually adjusts the threshold up to a predefined maximum adjustment so long as the detected weight is within a tolerance or hysteresis band, or a locking routine produces a step change adjustment of the threshold when the detected weight is outside the tolerance or hysteresis band for at least a predefined time.

The present invention discloses a modularized parallel digital control power harmonic active suppression method and its device. It includes N+1 digital control power harmonic active suppression modules which are parallelly connected to compensate harmonic wave, one of N+1 modules is redundant module, every module has a set of current sensors, and can be used for sampling electric network current from same point of non-linear load side, every module can calculate the harmonic current component from sampled electric network current, then the harmonic current component is phase-reversed, and multiplied by current-equalizing coefficient so as to obtain current instruction, then the hysteresis band control or triangle wave comparison control can be adopted to control output current and track current instruction change.

The invention discloses an asynchronous motor direct torque control method based on synthesized voltage vectors. The method includes three-phase current voltage is converted under alpha and beta coordinates through 3 / 2 conversion by detecting the current and voltage of the stator end of a motor, feedback torque and stator flux linkage vectors are calculated through an estimation module, the feedback value is compared with a given value, a torque hysteresis comparator is a zero hysteresis band, and a flux linkage PI controller replaces a flux linkage hysteresis controller to reduce flux linkage trajectory distortion; voltage spatial vectors are selected from a voltage vector selecting table to obtain voltage vector output; the control voltage vectors and zero voltage vectors in a sampling cycle are synthesized into a new voltage vector in a synthesized voltage vector pulse width modulation output signal controller. The method has the advantages that the given signals can be fast tracked by the flux linkage and torque controllers without offset, torque fluctuation and flux linkage trajectory distortion are reduced evidently, torque fluctuation is reduced greatly, and torque performance of system output is increased greatly.

The method of controlling a converter of a switched reluctance machine includes clocking a power switch with a frequency that depends on the width of the hysteresis band. The hysteresis width is varied according to reluctance machine speed, especially so that a difference between maximum and minimum values with which the current is switched on and off either increases with decreasing speed, decreases with increasing load, or both. The changing of the hysteresis width occurs so that a difference between maximum and minimum threshold values either increases with decreasing speed, decreases with increasing load, or both. The width of the hysteresis band preferably varies linearly with speed, load and / or current, especially so that the width of the hysteresis band varies linearly so that the clocking frequency is maintained substantially constant. Also targeted changes in the width of the hysteresis band are made to move the clocking frequency from near noise-critical resonance frequencies.

A control system for compensating a hysteresis band of a switched reluctance (SR) machine having a rotor and a stator is provided. The control system may include a converter circuit and a controller. The converter circuit may be operatively coupled to the stator and include a plurality of switches in selective communication with each phase of the stator. The controller may be in communication with each of the stator and the converter circuit, and configured to monitor at least one phase current of the SR machine relative to a current threshold of the hysteresis band, determine an adjustment value based on a difference between the phase current and the current threshold if the phase current exceeds the current threshold, and compensate the current threshold by the adjustment value.

The invention provides a multi-power supply control method, device and equipment and a multi-power supply system. The method comprises the steps that the real-time power of a load is monitored; if thereal-time power is monitored to be increased and the maximum threshold value of at least one hysteresis band is exceeded in the increasing process, the opening number of the power modules is adjustedaccording to the power supply opening number corresponding to the power supply interval to which the real-time power of the load belongs every time the maximum threshold value of one hysteresis bandis exceeded; and if the real-time power is monitored to be reduced and the real-time power of the load is lower than the minimum threshold value of at least one hysteresis band in the reduction process, the opening number of the power supply modules is adjusted according to the power supply opening number corresponding to the power supply interval to which the real-time power of the load belongs every time the real-time power is lower than the minimum threshold value of one hysteresis band. According to the method, the hysteresis band is arranged, so that frequent opening and closing of a certain power supply module possibly caused under the condition that the power fluctuates within a certain range are avoided, and the stability of the system can be effectively improved.

A method of regulating a phase current of an electric motor is provided. The method may include selectively enabling one or more switches of each phase of the electric motor according to one of at least a soft chopping motoring routine and a soft chopping generating routine, monitoring the phase current relative to a first hysteresis band, controlling the switches according to the soft chopping motoring routine when the phase current exceeds the first hysteresis band while operating according to the soft chopping generating routine, and controlling the switches according to the soft chopping generating routine when the phase current exceeds the first hysteresis band while operating according to the soft chopping motoring routine.

The method of controlling a converter of a switched reluctance machine includes clocking a power switch with a frequency that depends on the width of the hysteresis band. The hysteresis width is varied according to reluctance machine speed, especially so that a difference between maximum and minimum values with which the current is switched on and off either increases with decreasing speed, decreases with increasing load, or both. The changing of the hysteresis width occurs so that a difference between maximum and minimum threshold values either increases with decreasing speed, decreases with increasing load, or both. The width of the hysteresis band preferably varies linearly with speed, load and / or current, especially so that the width of the hysteresis band varies linearly so that the clocking frequency is maintained substantially constant. Also targeted changes in the width of the hysteresis band are made to move the clocking frequency from near noise-critical resonance frequencies.

A system and method for counting ridges in a captured print image frame is described. A pixel path through the captured print image frame is traversed. A hysteresis band for the pixel path is determined. A number of crossings of the determined hysteresis band is counted while traversing the pixel path. A number of print ridges based on the counted number of hysteresis band crossings is determined.

The invention discloses a cable hoist equipped with a hysteresis tension cradle frame. The two ends of the cradle frame body are rotatably connected with a winch frame through rotating shafts, and oneof the rotating shafts is provided with a current collecting ring. The cradle frame body is provided with a hysteresis brake. The current collecting ring is electrically connected with the hysteresisbrake. A large synchronizing wheel is connected on a cable coil. The hysteresis brake drives the large synchronizing wheel to synchronously rotate. The advantages of the cable hoist are that constantand steady pay-off tension of the cable on the cable coil is realized by using the method of providing stable damping through the hysteresis brake, the tension of each cable on each cradle frame is maintained to be consistent and the cost of the hysteresis brake is inputted in one time so that the maintenance cost is almost zero; the trouble of subsequent manual adjustment can be omitted; and tension adjustment is convenient, time-saving and labor-saving and visual and easy to understand, and the tension on each cable is displayed by numbers and can be adjusted in real time so that the twisting requirements of the high-flexibility cable can be met.

A system comprises a negative-pressure source including a pump and an electric motor for maintaining negative-pressure at the wound and a pressure sensor for sensing a wound site pressure (WP). The system further comprises a system controller coupled to the first pressure sensor and the electric motor. The system controller maintains the wound site pressure (WP) within a hysteresis band by the application of power to the electric motor from a battery power source, based upon, at least in part a flow rate (FR) of fluid between the pump and the wound site as determined by the system controller. The hysteresis band including a maximum wound site pressure (WPMax) and a minimum wound site pressure (WPMin).

The invention discloses a method of selecting an inverter sliding mode controller coefficient. The method is characterized by firstly, establishing a phase variable model of a full bridge inverter; and then combining a sliding mode controlling principle and an inverter work principle to construct a switching function s and selecting a sliding mode control law uc; and combining an existence condition and an accessibility condition of a sliding mode to deduce the existence condition of the sliding mode and a boundary value calculating formula of the sliding mode; and finally determining a hysteresis band width. In the invention, according to an expected design index and a main circuit known parameter, the formula can be directly used to calculate a needed sliding mode coefficient; a sliding mode controller coefficient formula design method is simple and easy to operate; because a maximum overshoot is determined to be a sliding mode domain positive boundary, when a zero load is changed into a full load, the designed sliding mode coefficient can guarantee rapidity and robustness of an inversion system response. By using the method in the invention, a problem that the sliding mode coefficient can not be accurately selected is solved and connection is directly established with an inverter expectation performance index.

The invention discloses a trapezoidal wave back electromotive force brushless direct current motor commutation error compensation method and belongs to the technical field of brushless direct currentmotor control. The brushless direct current motor commutation error compensation method comprises the following two steps of firstly, obtaining a primary estimation value of a commutation error basedon a mathematical model of the brushless direct current motor so as to improve the compensation speed of the commutation error; and performing online rolling optimization based on the difference valueof the phase current integration to obtain an optimal commutation error, and performing hysteresis control after the online rolling optimization is finished. Meanwhile, in order to adapt to the change of the rotating speed and the load of the motor, selection of the width of the hysteresis band is optimized to overcome the influence of uncertainty on hysteresis control. The trapezoidal wave backelectromotive force brushless direct current motor commutation error compensation method has the advantages of high compensation speed, high compensation precision, insensitivity to changes of motor rotating speed, load and the like and the like, and is beneficial to improving commutation precision and operation efficiency of the brushless direct current motor.

The invention discloses a method for controlling a power supply of an electron-optical circuit system of an electron beam furnace and a power supply device. The method takes the extraction value of an acceleration voltage sampling signal of a power supply of an electron beam generating system as a control signal for a focusing and deflection scanning power supply and the amplitude of a focusing and deflection scanning current changes linearly according to the control signal, which ensures that the operation parameter of the electron-optical circuit system is free from the influence of the fluctuation of the acceleration voltage. The power supply device has the acceleration voltage sampling signal connected with a square root extractor first and then connected to a focusing and deflection scanning power supply control circuit, and adopts a hysteresis-band current tracking pulse modulation controller to maintain a small up and down oscillation amplitude of a working current based on an expected value. An extraction value signal of the acceleration voltage sampling signal is used to control a focusing current, and a general control signal which is the produce of a deflection scanning integrated signal and the extraction value of the acceleration voltage sampling signal is used to control deflection scanning current, so the focusing and deflection scanning region of the electron beam is not influenced by the acceleration voltage, and in event of failure, the change of the focusing and deflection scanning region of the electron beam is controlled in a permitted range.

A hysteresis control method for inverter and an inverter based on hysteresis control are disclosed. The inverter is electrically connected to a power grid, and the method includes: Step S1, sampling a grid voltage Vg(z) and an output current Ig(z) of the inverter; Step S2, calculating a present period hysteresis bandwidth H(z) based on the grid voltage Vg(z) sampled in step S1; Step S3, predicting a next period hysteresis bandwidth H(z+1); Step S4, correcting the present period hysteresis bandwidth H(z) based on the next period hysteresis bandwidth H(z+1) obtained in step S3, to obtain a final hysteresis bandwidth Hout(z); and Step S5, controlling an output driving signal according to the output current Ig(z) of the inverter and the final hysteresis bandwidth Hout(z) to control the operation of the inverter.

A dead time control method (100) comprising the steps of: converting the DC link voltage, output current and output voltage to digital values with an ADC (Analog to Digital converter) (102); calculating the hysteresis band for adaptive hysteresis current control using the values read by the ADC and updating the band value via recalculating it at each sampling time (103); calculating the IrefH and IrefL values using the hysteresis band and Iref (103a); generating the PWM signal by hysteresis current control (104), generating two auxiliary control signals as VP, VN (105); in the region where VP=1 and VN=0, applying of the drive signal of T1 without setting dead time wherein T1 is the conduction duration of an upper switch, and not applying the drive signal of T2 wherein T2 is the turn off duration of said upper switch and is the conduction duration of a lower switch (106).

A hysteresis control method for inverter and an inverter based on hysteresis control are disclosed. The inverter is electrically connected to a power grid, and the method includes: Step S1, sampling a grid voltage Vg(z) and an output current Ig(z) of the inverter; Step S2, calculating a present period hysteresis bandwidth H(z) based on the grid voltage Vg(z) sampled in step S1; Step S3, predicting a next period hysteresis bandwidth H(z+1); Step S4, correcting the present period hysteresis bandwidth H(z) based on the next period hysteresis bandwidth H(z+1) obtained in step S3, to obtain a final hysteresis bandwidth Hout(z); and Step S5, controlling an output driving signal according to the output current Ig(z) of the inverter and the final hysteresis bandwidth Hout(z) to control the operation of the inverter.

A powertrain system is described, including a method for controlling a control variable for an element thereof. The method includes determining an initial state transition threshold and an associated hysteresis band for an operating parameter related to the control variable. The hysteresis band is decayed based upon operation in a present state of the control variable for powertrain element, and a preferred control variable for the powertrain element is selected based upon a comparison of the operating parameter and the initial state transition threshold accounting for the decayed hysteresis band for the operating parameter. The element of the powertrain system is controlled to the preferred state for the control variable.

A method of regulating a phase current of an electric motor is provided. The method may include selectively enabling one or more switches of each phase of the electric motor according to one of at least a soft chopping motoring routine and a soft chopping generating routine, monitoring the phase current relative to at least one limit of a hysteresis band and a switching period, and controlling the switches according to a hard chopping routine when the phase current does not reach the limit within the switching period.

A system comprises a negative-pressure source including a pump and an electric motor for maintaining negative-pressure at the wound and a pressure sensor for sensing a wound site pressure (WP). The system further comprises a system controller coupled to the first pressure sensor and the electric motor. The system controller maintains the wound site pressure (WP) within a hysteresis band by the application of power to the electric motor from a battery power source, based upon, at least in part a flow rate (FR) of fluid between the pump and the wound site as determined by the system controller.The hysteresis band including a maximum wound site pressure (WPMax) and a minimum wound site pressure (WPMin).