851 results about "Current compensation" patented technology

A system and method for organizational risk based on personnel planning factors is provided. Each employee has an employee profile data area that is used to store planning data and actual data corresponding to the employee. Planning data includes risk analysis data, compensation data, and development planning data. Actual data includes current compensation data and performance data. Inhibitors and motivators corresponding to employees is used to determine a flight risk that pertains to the employee. A contribution level, corresponding to the employee's contribution to the organization, is analyzed along with the flight risk to determine a risk quadrant that is assigned to the employee. Managers can select a risk quadrant and obtain information about common inhibitors and motivators. Incentive data, such as stock options, compensation, and awards, is planned in light of an employee's risk quadrant in order to motivate high contributors to remain with the organization.

An RMS-to-DC converter implements the difference-of-squares function by utilizing two identical squaring cells operating in opposition to generate two signals. An error amplifier nulls the difference between the signals. When used in a measurement mode, one of the squaring cells receives the signal to be measured, and the output of the error amplifier, which provides a measure of the RMS value of the input signal, is connected to the input of the second squaring cell, thereby closing the feedback loop around the second squaring cell. When used in a control mode, a set-point signal is applied to the second squaring cell, and the output of the error amplifier is used to control a variable-gain device such as a power amplifier which provides the input to the first squaring cell, thereby closing the feedback loop around the first squaring cell. Accurate square law approximation at microwave frequencies can be achieved by implementing the squaring cells as series-connected three-transistor multi-tanh transconductance cells. By using carefully balanced squaring cells and a well-balanced error amplifier, approximation errors are cancelled and accurate RMS measurement is realized at high frequencies. A feedforward bootstrapping feature uses an op amp to balance the voltages at the common nodes of the transconductance squaring cells and also provides a balanced differential input drive to one of the squaring cells. A base current compensation circuit for providing accurate base compensation current to both of the squaring cells prevents errors due to DC offset voltages.

A single replica current is proportional to current through a main switch of a switching power converter. This replica current may be used for current compensation, detection and response to an overload, detection and response to a super-overload, and combinations thereof. An input voltage is switchably coupled to an output signal generating a load current responsive to a switch control. A replica switch generates a replica current proportional to the load current. A ramp modulation signal may be generated. A voltage ramp of the ramp modulation signal may be adjusted in response to the replica current. A feedback difference signal is compared to the ramp modulation signal to generate a comparison output. Comparison of an overload reference voltage to a replica voltage proportional to the replica current generates an overload signal. The switch control is generated responsive to the comparison output and may be modified responsive to the overload signal.

The invention provides a compensating method of the switching frequency of a amplifier which comprises the following steps: two output end polarities is compared in the state in which the amplifier has no signal outputting; the inputting end current of the amplifier is adjusted according to the electrode; repeated circle is carried out until achieving the requirement of stopping the cycle. The invention also provides a compensating device of the DC offset voltage of the amplifier which comprises a comparator, a register, a decoding module and a current compensation module. The invention has the advantages of simple structure, low cost, small power-consumption. Meanwhile, the invention is used both for a signal amplifier and an amplifier system, which can limit the imbalance voltage to be in small scope.

The invention discloses a space vector modulation based harmonic current compensation system for a high-speed permanent magnet motor. The system comprises a rotor position and speed observation module, a stator phase current harmonic compensation module, a phase current feedback module, a rotation speed PI adjustment module, a current PI adjustment module and an SVPWM (space vector pulse width modulation) conversion output module. The stator phase current harmonic compensation module comprises a harmonic current extraction module, a proportional controller, a harmonic current adjustment module and a harmonic voltage compensation amount calculation module. The harmonic current extraction module extracts phase current harmonics of a permanent magnet synchronous motor in real time by the aid of an adaptive band-pass filter; the proportional controller adjusts the harmonic current and feeds the harmonic current to a current loop; the harmonic current adjustment module and the harmonic voltage compensation amount calculation module are used for calculating harmonic voltage compensation amount on the basis of a mathematical model of the high-speed permanent magnet motor and feeding back to the voltage loop. By the space vector modulation based harmonic current compensation system for the high-speed permanent magnet motor, voltage compensation amount can be calculated accurately, real-time compensation can be realized, phase current waveforms in operation of the permanent magnet synchronous motor can be improved effectively, torques and rotation speed pulses can be reduced, and accordingly operation efficiency, stability and reliability of the motor can be improved.

The invention discloses a grounding line selection method, a grounding line selection device and an application system based on an active component of a zero sequence current. The grounding line selection method and the grounding line selection device based on the active component of the zero sequence current are used for a distribution network system comprising a plurality of outgoing lines and a bus for grounding line selection protection when single-phase grounding failure occurs. The grounding line selection method comprises the steps of: zero sequence current compensation for compensating measured value of the active component of the aero sequence current of each outgoing line according to the distribution situation of the active component of the aero sequence current of the plurality of outgoing lines; line selection after the compensation, which is used for sequencing the active components of the compensated zero sequence currents of the plurality of outgoing lines according to the amplitude size and selecting the outgoing line the zero sequence current of which has maximum active component amplitude; and line selection protection which is used for comparing the maximum active component amplitude of the outgoing line of the zero sequence current with the threshold value, judging that the branch of the outgoing line is the grounding failure line if the maximum active component amplitude is more than the threshold value, otherwise, judging that the branch of the outgoing line is the bus grounding line if the maximum active component amplitude is less than the threshold value.

The invention relates to the field of motor control, and discloses an overvoltage protection device, an overvoltage protection method and an electrolytic-capacitor-free motor driving system. The overvoltage protection device comprises a voltage detection module for detecting direct-current bus voltage Vdc in real time, a current compensation dosage calculation module which is connected with the voltage detection module and is used for calculating a current compensation value according to the detected direct-current bus voltage Vdc and a preset safety voltage Vdc_max, and a current control module which is connected with the current compensation dosage calculation module and is used for generating a final current instruction value according to the calculated current compensation value and an initial current instruction value and adjusting three-phase current input into a motor by an inverter according to the final current instruction value in order to avoid overvoltage damage of the electrolytic-capacitor-free motor driving system. Through adoption of the voltage protection device and method and the electrolytic-capacitor-free motor driving system, the three-phase current of the motor can be adjusted according to the direct-current bus voltage detected in real time and the preset safety voltage, so that over high direct-current bus voltage is lowered, and the aim of overvoltage protection is fulfilled.

A backlight system for use in an LCD display with a driver providing current sink control includes an LED array module, a current feedback circuit, and a current compensation circuit. The LED array module has N columns of LEDs and each LED column has M LEDs connected in serial, wherein the current feedback circuit includes N current feedback units and the current compensation circuit includes N current compensation units, both of the current feedback circuit and the current compensation circuit being electrically coupled to the LED array module. When the backlight system is in operation, a current passes through an LED column, a current feedback unit, and a current compensation unit to generate an output voltage that is used for comparison with a predetermined DC voltage, and the current is compensated based on the results of the comparison.

In a case where a computing period of a torque ripple compensation section which computes current compensation values Δid and Δiq to be caused to flow into a motor in order to prevent occurrence of a torque ripple in the motor differs from a control period of a current control section which controls a feedback to the motor in such a way that current command values i*d and i*q additionally provided with the current compensation values Δid and Δiq flow into the motor, the microcomputer sets the current compensation values Δid and Δiq to zero when a rotor angular velocity ωre of the motor is equal to or greater than a first threshold value ω₁.

A system and method for controlling voltage at a point of common coupling of a wind farm including a plurality of wind turbines is provided. The method includes: calculating a first voltage error value, which is a difference between a reference voltage value of the point of common coupling and an actual voltage value of the point of common coupling; calculating a compensation reference voltage value based on the first voltage error value; calculating a second voltage error value by subtracting a voltage value of an output terminal of a wind turbine from a sum of a reference voltage value of the wind turbine and the compensation reference voltage value; calculating a reactive power compensation value corresponding to the second voltage error value; and injecting a reactive current corresponding to the reactive current compensation value into a power grid.

There are provided an apparatus and a method for controlling the power quality of a power generation system. According to the present invention, there is provided an apparatus for controlling the power quality of a power generation system including a DC/AC inverter converting DC voltage into AC voltage and supplying inverter current to a grid, including: a grid voltage phase follower generating a grid signal; a fundamental extractor extracting a magnitude of a fundamental wave of a load current introduced into a non-linear load connected between the DC/AC inverter and the grid; a first calculator subtracting a preset current compensation value from the magnitude of the fundamental wave from the fundamental extractor; and a second calculator generating an inverter current instruction value for the DC/AC inverter by using the output value of the first calculator and the grid signal and the load current from the grid voltage phase follower.

A switching power supply apparatus produces an output voltage by smoothing a pulsating voltage obtained by switching an input direct-current voltage with a switching device. The switching power supply apparatus has a current detection circuit that outputs a detection current that varies in proportion to the switch current flowing through the switching device, an overcurrent detection circuit that detects an overcurrent by comparing the detection current with a set current previously set so as to correspond to the overcurrent detection level and that, on detection of an overcurrent, feeds a reset signal to a flip-flop for controlling the switching of the switching device to turn the switching device off, and a second current compensation circuit that superimposes a compensation current on the detection current fed to the overcurrent detection circuit to produce a compensated current.

A system and method for personnel management collaboration is provided. Each employee has an employee profile data area that is used to store planning data and actual data corresponding to the employee. Planning data includes risk analysis data, compensation data, and development planning data. Actual data includes current compensation data and performance data. A management team may have a common project manager with many department managers. The project manager selects employees normally included in the project manager's view, such as the department managers, and excludes them to form a new view in order to protect the confidentiality of the department manager's data. The new view can be shared amongst the department managers without compromising confidentiality. Employee data pertaining to employees reporting to the department managers is still included in the view for collaborative management meetings and online discussions. Changes to employee data are visible to all of the managers.

A voltage regulator having an input terminal for receiving an input voltage and an output terminal for providing a regulated voltage, the voltage regulator including: a differential amplifier configured for receiving a reference voltage and a feedback signal being a function of the regulated voltage, and for providing a regulation signal according to a comparison between the reference voltage and the feedback signal, a regulation transistor having a control terminal for receiving the regulation signal, a first terminal for receiving the first voltage and a second terminal coupled with the output terminal of the voltage regulator, wherein a voltage-controlled circuit coupled to the output terminal, responsive to a voltage difference between the first voltage and the regulation voltage and adapted to sink from the output terminal a current depending on said voltage difference between the supply voltage and the regulation voltage, said current being related to a leakage current of the regulation transistor.

The invention provides an integration switch power supply controller and a switch power supply using the same. The integration switch power supply controller comprises a multiplexing pin, wherein the multiplexing pin is used for receiving a detection voltage signal. In each switching period, within a first time interval, the detection voltage signal is in proportion to a direct current input voltage of the switch power supply, and a current compensation signal is generated according to the detection voltage signal so as to acquire a peak current of inductance flowing through the switch power supply; within a second time interval, the detection voltage signal is in proportion to an output voltage of the switch power supply, and a discharge time span of an inductive current is acquired according to the detection voltage signal; and within a third time interval, the detection voltage signal is in proportion to a voltage between two power ends of a power switching element of the switch power supply, and the integration switch power supply controller controls the power switching element to be on-state at a valley bottom moment according to the detection voltage signal.

The invention discloses a rotating control method of a crane, a rotating control system and the crane. The rotating control method of the crane comprises the following steps of: obtaining the current working condition parameters of the crane; finding current regulation coefficients corresponding to the current working condition parameters in a preset mapping table; obtaining a current value of a proportional electromagnetic valve corresponding to an opening degree of an operating handle; performing compensation calculation on the current value of the proportional electromagnetic valve according to the current regulation coefficients so as to obtain a control current compensation value; and outputting control current to a rotating actuation mechanism with the control current compensation value. Through the application of the technical scheme, a control component utilizes preset mapping relationship to obtain the corresponding current regulation coefficients at working state according to the current working state signal of the crane, and corresponding adjustment is performed on the current of the proportional electromagnetic valve so as to ensure that the rotating speed of the crane cannot exceed the maximum rotating speed limit value at the current working state, so that the possibility that a lazy arm is damaged is reduced, and the safety performance of the crane is improved.

The invention relates to an electronic ballast of an alternate current high-power LED illumination energy-saving lamp, which belongs to the field of electric illumination energy conservation. The electronic ballast comprises a casing and a control circuit in the casing, and is characterized in that the control circuit comprises a rectifying circuit, a PFC power factor correction circuit, a light energy conversion controller circuit, an LED luminous device, a constant current drive control circuit, a loop current detection circuit, and the like; the main circuit of the rectifying circuit is connected with a follow current compensation circuit via the PFC power factor correction circuit and a power filter circuit; a bypass circuit of the rectifying circuit is connected with a controller power supply circuit which is respectively connected with a linear dimming circuit and the light energy conversion controller circuit; the loop of the LED luminous device is connected with the constant current drive control circuit and then is connected with the loop current detection circuit; and the loop current detection circuit is connected with the light energy conversion controller circuit. The electronic ballast has the advantages of small volume, simple structure, high electricity saving efficiency, long service life, and the like.

The invention relates to a non-isolated AC-DC (Alternating Current-Direct Current) LED driver peak current compensation method. The method ensures that an LED driver controlled by peak current can maintain constant LED current within different input voltage ranges and on the condition of driving different quantities of LEDs, and then the brightness of the LEDs is remained unchanged. On the basis of peak current control, a current peak is compensated according to input voltage and the quantity of output LEDs so as to ensure that average current flowing through the LEDs maintains constant.

The invention discloses a ground fault current compensation system and method for a self-produced power supply phase power supply. The system comprises a phase power supply generator, a phase power supply phase compensator, a fling-cut switch, a controller and a voltage transformation device. An output end of a phase compensator of a power supply is connected to a system neutral point through thefling-cut switch. The system can passively generate power distribution network power supply phase power supply and harmonic phase power supply and input anti-phase power supply phase power supply andthe harmonic phase power supply into the system according to fault logic. The complete compensation of power distribution network grounding fault reactive current, harmonic current and active currentis achieved, the defect that compensation is incomplete by adopting a power electronic device inversion injection method after electricity is taken from a bus system is overcome, and the problems thatan active inversion method has a poor metallic grounding compensation effect and a traditional arc suppression coil cannot achieve full compensation are solved. The system is efficient and accurate and can completely compensate overvoltage and overcurrent generated by a grounding fault, the safety of a power grid and equipment is guaranteed, and the risk of electric shock of a human body is completely avoided.