301 results about "Current loop control" patented technology

A new current loop control system method is proposed for a single-phase grid-tie power conditioning system that can be used under a standalone or a grid-tie mode. This type of inverter utilizes an inductor-capacitor-inductor (LCL) filter as the interface in between inverter and the utility grid. The first set of inductor-capacitor (LC) can be used in the standalone mode, and the complete LCL can be used for the grid-tie mode. A new admittance compensation technique is proposed for the controller design to avoid low stability margin while maintaining sufficient gain at the fundamental frequency. The proposed current loop controller system and admittance compensation technique have been simulated and tested. Simulation results indicate that without the admittance path compensation, the current loop controller output duty cycle is largely offset by an undesired admittance path. At the initial simulation cycle, the power flow may be erratically fed back to the inverter causing catastrophic failure. With admittance path compensation, the output power shows a steady-state offset that matches the design value. Experimental results show that the inverter is capable of both a standalone and a grid-tie connection mode using the LCL filter configuration.

The invention provides a grid-connected generation control method for a photovoltaic power generation converter. The method comprises the following steps of: grid voltage software phase lock, voltage outer loop establishment, current control and grid voltage orientated vector control, wherein the grid voltage software phase lock adopts a software three-phase phase-locked loop method; a phase-locked loop consists of a phase detector, a loop filter and an oscillator; the grid voltage orientated vector control adopts a double-closed-loop cascade control structure, namely a voltage outer loop and a current inner loop; the voltage loop controls a direct-current bus voltage; and the current loop controls an alternating-current side input current. By the method, the orientation is accurate, the direct-current bus voltage is controlled to be stable, and maximum power point tracking control is realized. Deadbeat control design is performed aiming at the current loop, so that the current loop controls the alternating-current side input current according to a current command given by the voltage loop and unit power factor operation is realized. By adopting a feedforward decoupling control method, stable grid-connected operation can be realized.

Methods and apparatus for control of DC-DC converters, especially in valley current mode. The DC-DC converter is operable so that a low side supply switch may be turned off, before the high side supply switch is turned on. During the period when both switches are off the current loop control remains active and the change in inductor (L) current is emulated. One embodiment uses a current sensor for lossless current sensing and emulates the change in inductor current by holding the value of the output of the current sensor (ISNS) at the time that the low side switch turns off and adding an emulated ramp signal (VISLP) until the inductor current reaches zero. Embodiment employing a pulse-skip mode of operation based on a minimum conduction time are also disclosed. The invention enables a seamless transition from Continuous Conduction Mode the Discontinuous Conduction Mode and Pulse Skipping and provide converters that are efficient at low current loads.

The invention discloses a low voltage ride through control method for a high-power photovoltaic inverter. The method comprises the following steps: firstly, considering a low voltage ride through situation under the condition of grid voltage sag, particularly unbalanced sag on the basis of a high-power photovoltaic inverter structure of an LCL filter, calculating reference given values of positive sequence current and negative sequence current specific to the control aim of restraining the negative sequence current, and compensating idle work of filter capacitor absorption via a control algorithm to ensure high-power-factor grid connection while running at different power levels; secondly, designing to add a filter capacitor current feed-forward signal into a modulation signal on the basis of positive and negative sequence double current loop control, and adjusting a feed-forward coefficient to realize active damping control under unbalanced control; and lastly, designing a disturbance quantity feed-forward coefficient to restrain transient current impact. Due to the adoption of the method, current impact at the moment of grid voltage sag can be restrained effectively, three-phase balanced output of current before and after grid voltage sag is ensured, and the control effect meets the electric energy quality requirement of a power grid on the grid connection of the photovoltaic inverter.

The invention discloses a method for restraining subsynchronous oscillation caused by grid connection of a draught fan based on SVG. The method includes firstly measuring frequency of subsynchronous oscillating current of a power grid, performing FFT analysis, and thereby obtaining all subsynchronous oscillating frequencies. The difference between the working frequency and the subsynchronous current oscillating frequency of the system is set as the central frequency of a band-pass filter for designing the BPF (Band-Pass Filter). The SVG current loop control design namely includes decoupling under a DQ rotating coordinate system, and enabling subsynchronous oscillating current signals obtained through detecting under the DQ rotating coordinate system to pass through the filter to obtain reactive current commands. The compensation strategy for compensating subsynchronous oscillation caused by grid connection of wind power in a distributed manner namely includes: through the design of distributed SVG compensation points, increasing capacity of the SVG for compensating subsynchronous oscillating current of the power grid, and restraining the problem of subsynchronous oscillation caused by grid connection of wind power at different nodes in a targeted manner.

The invention relates to a method for controlling a rotary speed of a magnetically suspended flywheel. The method comprises the following steps of: according to a feedback value of the rotary speed of the magnetically suspended flywheel, performing fuzzy adaptive kalman filtration of the feedback value of the rotary speed, performing rotary speed loop control of the magnetically suspended flywheel according to the rotary speed reference value and the filtered rotary speed value, adaptively adjusting the rotary speed loop control parameters according to the rotary speed reference value and the rotary speed deviation, and outputting the current reference value by the rotary speed loop; performing the current loop control according to the current reference value and the current feedback value; and finally, by adjusting the current value of a motor winding, realizing the high-precision control of the rotary speed of the magnetically suspended flywheel in the full-rotary speed range. The method belongs to the technical field of aerospace control, and can also be applied to the high-precision control of other dc brushless motors.

The invention relates to a double-current loop control method of an LCL (Inductor Capacitor Inductor) filtering grid-connected inverter, belonging to the field of inserter control. The method comprises the steps of: respectively sampling inductive currents at a grid side and inductive currents at an inverter bridge side by using two groups of current sensors; respectively converting the inductive currents ia1, b1 and c1 at the grid side and the inductive currents ia2, b2 and c2 at the inverter bridge side under a stationary coordinate system into currents id1 and q1 as well as id2 and q2 under a two-phase rotating coordinate system; and then by taking id1 and id2 as feedback variables of an active current control loop and taking iq1 and iq2 as feedback variables of the active current control loop, sending output signals of the two control loops and phase signals of a power grid voltage to a SVPWM (Space Vector Pulse Width Modulation) module, wherein the SVPWM module is used for outputting corresponding switch driving signals so as to control the quality of grid current waveform of the inverter. The method disclosed by the invention has the advantages of high control precision, high power factor, convenience for protecting a bridge-arm switching tube and the like.

A voltage converter includes a transformer with a pair of primary coils and a secondary coil. The converter has a DC input and a capacitor bank, having a pair of capacitors, is connected across the DC input. A switch is associated with each primary coil. A gate drive feedback module outputs a pulse width modulated signal to drive either the first or second primary coil. A gate drive switch has as an input the pulse width modulated signal and outputs to the first second switch. A pulse steering logic module determines which of the first or second capacitors has a higher voltage and controls the gate drive switch to direct the pulse width modulated signal in response thereto.

The invention discloses an improved current loop control method for a photovoltaic grid-connected inverter, and belongs to the technical field of solar photovoltaic power generation. The method comprises the following steps that: a voltage feedforward control quantity u1 is obtained through commercial electricity voltage feedforward; 2, a current error [delta]i is obtained through a voltage outer loop control structure; 3, the current error [delta]i is segmented for forming a plurality of current error segments, each current error segment adopts different gains, and a current equivalent voltage duty ratio control quantity u2 is obtained after the current passes through a current inner loop control structure adopting a controller P; and 4, a command value u_order of a switch comparison register is obtained. The control method provided by the invention has the advantages that the realization is simple; complicated integral and differential coefficient setting is not needed; the introduction of virtual orthogonal signals is not needed; time-consuming dp coordinate transformation is avoided; meanwhile, the output current distortion can be effectively reduced; and the resistance capability on electricity grid distortion and harmonic interference is enhanced.

The invention relates to a converter reactive power control method and system based on a virtual synchronous generator model, and belongs to the technical field of power grid control. The invention combines a power control technology based on a virtual synchronous generator and a current loop control technology based on a positive and negative sequence d-q dual-rotation coordinate system, and discloses a negative sequence reactive power control method under the condition that a power grid or a load is asymmetric. According to the converter reactive power control method and system based on the virtual synchronous generator model, power grid adaptability and operation stability of a converter are promoted, supporting on a grid connection point voltage is effectively assisted in, and quality of the grid connection point voltage is improved.

The invention relates to a method for measuring the joint torque through an optical-electricity encoder. By the adoption of the method, the joint torque can be measured more simply and accurately. The method comprises the steps that S1, an angle value signal of the angle position change of a flexible wheel shaft relative to a joint output shaft in the motion process of a motor is collected by a signal collecting circuit of the optical-electricity encoder in real time; and S2, the angle value signal collected in the step S1 is received through a joint controller and subjected to calculation processing. The step S2 specifically comprises the substeps that S21, the torque T of each linear spring in an elastic unit is obtained through calculation; and S22, the torque of the joint output shaft is obtained by superimposing the torques T of all the linear springs in the elastic unit. The invention further relates to a control method of a robot joint, the obtained torque value is compared with a torque reference value and a joint torque compensation value, a torque difference value is obtained, then the torque difference value is converted into a motor control signal through a torque current loop control module, and finally operation of the motor is controlled, so that simpler and more accurate control over the joint is achieved.

The invention discloses a single-current-sensor-based current loop control method and apparatus of a motor. The single-current sensor is used for detecting a current of a direct-current bus. The method comprises: a starting time of a current PWM half cycle is detected, and a first AD sampling trigger time and a second AD sampling trigger time of the current PWM half cycle are obtained when the starting time of the current PWM half cycle is detected; according to the first AD sampling trigger time and the second AD sampling trigger time, a first direct-current bus sampling current and a second direct-current bus sampling current are sampled correspondingly; and after completion of second-time sampling, a three-phase PWM waveform is outputted based on the first direct-current bus sampling current and the second direct-current bus sampling current to carry out current loop controlling on a motor, and a PWM phase-shift parameter of a next PWM half cycle, a first AD sampling trigger time, and a second AD sampling trigger time are generated according to the outputted three-phase PWM waveform. Therefore, the delay of the current loop can be reduced to be within a half PWM cycle and thus the current loop delay time is shortened.

A motor control apparatus includes: a PWM rectifier; an inverter; a detection unit for detecting an AC voltage value of the PWM rectifier; a calculation unit for calculating a power supply voltage phase; a detection unit for detecting an AC current value of the PWM rectifier; a current loop control unit for generating an AC voltage command to control a power conversion operation of the PWM rectifier; a current loop saturation state determination unit for determining to be in a current loop saturation state when a magnitude of the AC voltage command is equal to or larger than a predetermined voltage prescribed value; an operation determination unit for determining whether the PWM rectifier is in a powering operation or in a regenerative operation and a power failure determination unit for determining a presence or absence of a power failure at the AC power supply side from the determination results.

The invention discloses a control system and a control method of three-phase independent control grid inversion, wherein the control method of the three-phase independent control grid inversion comprises the steps: 1, error information between an electric supply phase angle and a lock phase angle is obtained by a DQ lock phase based on a closed ring lock phase of the three-phase system of a synchronous rotation coordinate system; 2, the voltage ring adopts comparison between the input voltage and the reference voltage; the obtained error signal is used as a current loop reference after being controlled and outputted by PI to perform PI control; 3, the electric supply valid value and the angle of the single-phase DQ lock phase are combined to replace the electric supply to generate a new front feed signal; and 4, the output of the current loop control and the quantity of the front feed control are used as final output quantity to be used as a modulation signal of SPWM (sinusoidal pulse width modulation) modulation so as to drive the inverter, therefore, the whole three-phase grid inverse system can run.

The invention relates to the technical field of alternating current servo vector control, and discloses a current loop control system based on an FPGA, and a servo device. According to the system and the device, through adoption of current loop control based on an FPGA hardware logic parallel processing mode, a current given quantity and signals sent by a current sampling module are input into a current controller module for PID calculation and decoupling compensation processing, a voltage vector reference value under a rotating coordinate system is output; a voltage vector reference value under a static coordinate system is output according to a rotor angle value output by an encoder feedback module and the output voltage vector reference value under the rotating coordinate system; a space vector pulse width modulation module converts the voltage vector reference value under the static coordinate system into three-way effective duty cycles; a complementary output pulse width modulation module with dead zone insertion converts the three-way effective duty cycles into six-way pulse width modulation square signals after dead-time compensation. Through adoption of the system and the device, the current loop control time is reduced, and the current loop bandwidth is improved.

The embodiment of the invention discloses a method for controlling a photovoltaic inverter circuit. The method includes the steps that after a starting command is received, a positive total bus capacitor and a negative total bus capacitor are charged; after a first preset condition is met, charging operation is stopped, and a phase-locking loop of a power grid is controlled to conduct phase-locking operation; after the phase-locking loop finishes the phase-locking operation, a five-level inverter is started in a three-level mode, and voltage loop control and current loop control are conducted on the five-level inverter; when a second preset condition is met, a first Boost converter and a second Boost converter are controlled to be started without loads, and voltage loop control is conducted on the two Boost converters; after input voltage and input current of the first Boost converter and the second Boost converter are stable, the five-level inverter is controlled to run in a five-level mode. According to the method for controlling the photovoltaic inverter circuit, fluctuation of input voltage and input power of a solar cell array can be reduced when the photovoltaic inverter circuit is started, and the starting process is smoother. The invention further discloses a corresponding control device.

The invention discloses a power stable solid laser and a control method thereof. The power stable solid laser comprises a base inside which cooling water flows, a heat-conducting carrier for mountingand fixing an optical crystal of the solid laser, a temperature sensor disposed on the heat-conducting carrier, a semiconductor refrigeration unit disposed between the heat-conducting carrier and thebase and driven by a bipolar current driver, and a control unit. A temperature-current double closed-loop control system is realized on the basis of the conventional temperature control system; an inner loop is a closed current loop controlled by PI, and an outer loop is a closed temperature loop controlled by PID, so as to improve the control precision of the system, and finally achieve the purpose of improving the power stability of the solid laser.

The invention discloses a wireless charger suitable for any lithium battery, and belongs to the technical field of lithium battery wireless charging. The wireless charger uses a bilateral LCC compensation circuit as a topology, and at least two different frequency points are found by designing a set of compensation parameters, so that zero-reactive power is achieved, and the requirements for constant current and constant voltage needed by charging of any lithium battery are met. In order to achieve the work mode that constant current is obtained after constant voltage is obtained, firstly, a current loop controls a system to work in the constant-current mode, then the current loop is switched to a voltage loop when the voltage of the lithium battery reaches a constant-voltage charging threshold, and then the voltage loop controls the system to work in the constant-voltage mode. According to the wireless charger, direct-current converters do not need to be cascaded with a primary side and a secondary side, secondary voltage adjustment of front-stage or rear-stage DC / DC converters is not needed, the cost is reduced, the system complexity is reduced, and the reliability of the systemis improved.

The invention puts forward a modular multilevel converter (MMC) hierarchical control method. On the basis of the existing voltage-current and sub module control method, a current injection ring current suppression structure, a sub module capacitive voltage ripple suppression structure and a predicted composite voltage frequency and amplitude recovery control method are superimposed. Hierarchical control is divided into inner-ring basic control and outer-ring optimized control. The hierarchical control method is applicable to half-bridge sub module, full-bridge sub module and mixed-bridge sub module multilevel circuits. Inner-ring control comprises a voltage and current loop control structure, a sub module capacitive voltage ripple control structure, a ring current injection suppression control structure, and the like. Outer-ring control comprises a droop control structure, a predictive composite control structure, and the like. Ring current injection suppression control, sub module capacitive voltage ripple control and predictive composite control methods are put forward by the invention. The control method of the invention can help improve the stability of a system under different load conditions, improve the quality of output voltage and power of a DC transmission system, reduce the investment cost of a modular multilevel transmission system, and improve the anti-interference ability and rapid response ability of a transmission system.

A power converter module is disclosed, which is an all-digital module. The power converter module includes a reference voltage generation unit, a voltage loop control unit, a current loop control unit, an input voltage compensation unit, and a pulse width modulation generation unit, to transfer input power to stable output power for providing power to an external loading device through driving bridge switch unit with external driver. The voltage loop control unit and the current loop control unit contain a proportion-integral-differentiation controller for receiving signal related to voltage and current of loading device to form voltage control loop and current control loop. The pulse width modulation generation unit contains function of deciding necessary stop time to improve quality of output power and decrease the effect of input power and loading variation, and to provide stable sine-waveform output power to the external loading device.

The invention discloses a sliding mode adaptive controller with built-in brushless DC motor current loop control for a two-wheeled self-balancing robot. The controller at least comprises a sliding mode adaptive controller and a current loop active-disturbance-rejection controller, wherein the sliding mode adaptive controller is used for controlling an output motor torque T<w> according to an angle parameter Theta and an angular speed Theta-bar and converting the motor torque T<w> to a current i<*>, and the current loop active-disturbance-rejection controller is used for controlling an output voltage U<*><a0>(t) to drive a motor system to move according to the current i<*> and a motor current i detected by a sensor measurement module. With the adoption of the technical scheme disclosed by the invention, current loop control is added into the controller, thus, the size of the driving current is effectively controlled, a large current cannot be generated, the driving of a brushless motor is protected, the lifetime of a balance car is greatly prolonged, and the application safety of the balance car is greatly improved.

The invention discloses a linear-regulated PFC control circuit which comprises a PFC input voltage sampling module, a PFC input current sampling module, a PFC output voltage sampling module, a PFC control circuit module, a PFC output voltage-boosting power circuit module and a PFC linear regulation module, wherein the PFC linear regulation module is used for generating a linear regulation parameter of the linear regulation for the current loop control executed by the PFC control circuit module within the range from a heavy load to a light load according to the input current sampled by the PFC input current sampling module, and the PFC control circuit module is used for generating a wave generating signal of the linear regulation control for the PFC output voltage-boosting power circuit module according to the linear regulation parameter. An inner loop parameter is linearly regulated by utilizing the size of the load or the input current to finish effective wave shape control and obtain index optimization within a full-load range, and meanwhile, the overall efficiency within the light-load range is improved and the reactive power loss is reduced.

The invention provides a decoupling control method for a permanent magnet synchronous motor. The method includes the following steps that (1) an open-loop transfer function of a current loop controlled object of a motor model is constructed on a space vector coordinate system according to q-axis and d-axis voltage equations of the permanent magnet synchronous motor; (2) a current motor rotation speed is introduced to be added to a current loop of the motor model so that a complex vector PI regulator with a plurality of zero points can be constructed; (3) an integrating factor of the complex vector PI regulator is set in a complex vector PI control method, so that zero points of a transfer function of the complex vector PI regulator are equal to pole points of the open-loop transfer function of the current loop controlled object in number, and motor coupling influences are eliminated. The decoupling control method has the advantages that the structure with the complex vector PI regulator is adopted so that the complex vector PI regulator generates a plurality of zero points in the same quantity as the pole points of the current loop controlled object, cancellation conditions of zero and pole points are met, the motor coupling influences are effectively eliminated, stability of the motor operating at a high speed is improved and the decoupling control method is especially suitable for the field of electric vehicles.

The invention provides a control method for a servo speed-regulation system with load acceleration feedback. First, motor angular speed feedback is extracted for speed ring calculation to obtain an angular accelerated speed instruction; then angular accelerated speed of a load is extracted, the angular rate of an orientation gyroscope is collected, and a current loop controlled quantity is calculated by the utilization of angular accelerated speed feedback; a current loop controlled quantity is calculated according to MTPA; line current is collected to calculate alternate and direct shaft current of a PMSM under dq coordinates; finally, a dq shaft voltage controlled quantity serves as input of park conversion of the PMSM to complete control over the motor. With the control method, influences on tracking precision of shooting impact force borne by a gun servo load tail end can be effectively restrained, positive effects on solving of the problem of structural resonance between a transmission system and the load in the gun servo system and a tooth space non-linear problem in a transmission chain are achieved, and then the performance of the gun servo system is improved.

The invention relates to the technical field of motor control, and discloses a suppression method for bus voltage fluctuation in a high-voltage frequency converter. The suppression method for the bus voltage fluctuation in the high-voltage frequency converter includes the following step: adding zero-sequence components into modulating waves of an inverter of the high-voltage frequency converter. In this way, the bus voltage fluctuation of the high-voltage frequency converter can be suppressed, the adverse influence on current loop control of a PWM rectifier AFE is reduced, the lifetime of a capacitor in the frequency converter can be extended, and the damage to the sine degree of output waveform of the frequency converter is reduced.

The disclosed composite control method for injection-type hybrid active filter comprises: detecting harmonic current on load / power-network side to obtain the load / power-network harmonic current loop control output; detecting the access harmonie voltage of filter to obtain harmonic voltage loop control output; adding all output to obtain the command control signal. This invention eliminates the danger to active filter led by harmonic voltage.

The invention relates to a coordinated stable operation control method for an island DC micro-grid. By improving the double closed loop control of a conventional converter and using improved constant-voltage droop control, a current inner-loop control reference value is generated, and by introducing a SOC equalization factor into the current inner loop control, each energy storage unit dynamicallyadjusts the current inner-loop output current reference value according to its own capacity and a current SOC, and finally SOC equalization is achieved between the energy storage units connected in parallel. Compared with the prior art, the method eliminates the influence of the unmatched line impedance on the current load distribution accuracy, and does not produce a DC bus voltage drop similarto that caused by the conventional droop control.

A current loop control method of a permanent magnet synchronous motor relates to the current loop control method of a permanent magnet synchronous motor under the rotor field-oriented synchronous rotating coordinate axes, which comprises: acquiring stator current signal of the motor; detecting the position of the rotor of the motor, and computing the electrical angular velocity and the electrical angle; performing coordinate transformation for the stator current signal of the motor to obtain the d, q axis component of the stator current of the motor; establishing stationary equation set; establishing current loop control equation set; and undergoing coordinate transformation to obtain the switching signal of the motor operation. The invention has the benefit effect that the invention has higher voltage control precision, can meet the requirement of the high precision of different parameter motors within wider velocity range, and has high control precision, good dynamic performance, simple method and wider application range.

The invention discloses an active and reactive current coordination control-based photovoltaic grid-connected inverter control method. The method mainly comprises the steps of: firstly, introducing a capacitor current control loop into a two-stage grid-connected inverter based on a grid voltage orientation control strategy to form double current loop control; and secondly, setting a current reference value to give corresponding control strategies to a normal operation condition and a transient stability condition. The active and reactive current coordination control-based photovoltaic grid-connected inverter control method provided by the invention facilitates transient voltage recovery after a system is in a short circuit fault, and improves the transient stability of the system.

The invention relates to a phase-locked control method for zero-voltage ride through of a photovoltaic grid-connected inverter. Based on conventional positive-negative sequence dual-current loop control, a phase-locked control strategy of the photovoltaic grid-connected inverter is provided during zero-voltage fault ride through of a three-phase power grid. By simple treatment on proportion integral (PI) of a phase-locked loop, the phases of the output current of the inverter before and after zero-voltage fault are continuous, and current disorder and impact caused by loss of a reference voltage are prevented; and the method is simple and efficient, and the standard requirement of zero-voltage ride through of the inverter can be satisfied.