821 results about "Pi regulator" patented technology

The invention relates to an intelligent control device of a high power energy saving electromagnetic stove, and the method thereof, The intelligent control device comprises a controllable rectifying and filtering module, a contravariant module and a microcomputer controlling module, which is characterized in that a three-phase alternating current power supply is rectified into an adjustable direct current power supply through the controllable rectifying and filtering module ; the direct current power supply is inverted into a high frequency alternating current power supply through the contravariant module, and then the electric energy is converted into electromagnetic energy to be radiated to the bottom of a cookware, and vortex flow is generated, and the cookware can be heated because of the thermal effect of the vortex flow; the microcomputer controlling module is the core of the entire system, which is used for collecting data and transmitting control information to each module; the device adopts a series of advanced control policies, such as the trigger control of the rectifier bridge of an PI regulator, the intelligent self-adaptive constant power control, the intelligent soft-start control, the intelligent cookware detection control, etc., and thereby the working stability and the security of the electromagnetic stove are enhanced. The harmonic pollution of the equipment to the electric network can be reduced to the utmost extent when the electric energy of the electromagnetic stove is saved, and the electromagnetic stove is suitable for various kitchens and dining rooms.

The invention provides a field weakening control method for a built-in permanent magnet synchronous motor. The method comprises the following steps: motor speed closed-loop control in a field non-weakening region: the output of a speed loop is the current directive value i<*>q of an axis q, the current directive value i<*>d of an axis d is calculated from i<*>q according to an MTPA relation, and i<*>d, i<*>q and the actual feedback values id and iq thereof are subjected to closed-loop control to output the voltage directive values of the axis d and the axis q; difference value amplitude-limiting processing: whether to enter a field weakening region is judged, if yes, an output voltage amplitude value controls a PI (Proportional-Integral) controller to work and controls a PI adjustor to perform difference value amplitude-limiting processing and output Deltaiq, otherwise, the output voltage amplitude value controls the PI controller not to work, and the output is 0; in case of entering the field weakening region, the output i<*>q of the speed loop is only used as the current directive value of the axis d after MTPA calculation, and the sum of the output of the front beat of the speed loop before entering the field weakening region and Deltaiq serves as the current directive value of the axis q in the field weakening region.

The invention designs a control method of an inverter on a rotor side of a double fed wind induction generator. In the control method, a traditional PI adjustor is changed into a PIR adjustor, and a setting frequency Omega c in the PIR adjustor is set as a bisynchronous revolution angular speed Omega s, that is, a double frequency negative sequence component in disturbance quantity can be restrained completely, so the situation that power outputted to a power grid oscillates caused by impulsive motion of the electromagnetic torque of an engine because of unequal power grid voltage can be avoided. At the same time, the PIR adjustor can track a positive sequence component with frequency being zero and the double frequency negative sequence component in the forward path which are input in an astatic manner, thereby avoiding that unequal voltage aggravates the imbalance of stator current to cause a stator winding to heat because of serious imbalance. In addition, the control method realizes the control of the inverter on the rotor side of the generator under the condition of the unequal power grid voltage only through the replacement of the adjustor, the alteration thereof is simple, the effect is obvious, the design of complex elements is not involved, and the actualization is easy.

This invention discloses a dual-feed AC-DC-AC converter control structure for wind power generation, and the rotor exciting magnetic converter using the fuzzy PI adaptive control strategy of current inner loop. When the generator no-load networking, the current inner loop uses the conventional PI regulator, and after networking, as to three modes, sub-synchronization, synchronization, super-synchronous, it uses fuzzy adaptive PI control. The network-side converter uses SPWM control strategy which fixed switching frequency and combining electric network electromotive front-feed. In the invention, both converting processes use four-quadrant operation PWM converters based on full-controlled devices, so it can not only improve the system dynamic response, reduce wastage and impact, achieve the two-way electric transmission, but also it can achieve wind power generation network side unit power factor sinusoidal current networking power generation operating.

The invention discloses a permanent synchronization motor torque control method based on a sliding mode flux linkage observer. Direct torque control is performed on a permanent synchronization motor through a 3/2 coordinate conversion module, the sliding mode flux linkage observer, an electromagnetic torque calculation module, a rotating speed PI adjustor, a torque PI adjustor, a flux linkage self-adaptation module, an expected voltage calculation module, an SVPWM module and an inverter. The sliding mode flux linkage observer is adopted for estimating the size, phase and rotator speed of stator flux linkage, and set torque is processed through the flux linkage self-adaptation module to obtain a set value of the stator flux linkage. Expected voltage calculation is performed on size and phase estimation values and the set value of the stator flux linkage and the output quantity of the torque PI adjustor, so that two-phase alternating-current voltage reference values on a two-phase static coordinate system are obtained, and then through SVPWM conversion, a switching signal is obtained to drive the voltage source inverter to achieve direct torque control over the permanent synchronization motor.

This invention relates to nonvelocity sensor permanent-magnet synchro-motor-air conditioning compressor system. It is characterized by that nonvelocity sensor vector control is used for permanent-magnet synchromotor, so, overcoming the shortcoming of the large rotating speed pulsation. At the same time, the torque command current composite control method is used to make further lowering rotating speed pulsation of the motor. It overcomes the problem of unsatability of the system during the procedure of regulating PI regulator parameter in traditional vector control system.

The invention discloses a double-tube Buck-Boost type PFC (Power Factor Correction) converter based on one-cycle control, a bridge rectification circuit is then connected with a BOCBB type double-tube Buck-Boost converter; one path of output signal of a PI (proportion integral) adjuster is sent to a noninverting input end of a comparator, the other path of output signal is superposed with a sampling signal of input current and then is sent to a resettable integrator, an output end of the resettable integrator is connected with an inverting input end of the comparator, an output end of the comparator is connected with an RS (remote sensing) trigger, one end of the RS trigger is connected with a reset switch of the resettable integrator, and a Q-end output signal of the RS trigger simultaneously drives two switching tubes of the BOCBB type double-tube Buck-Boost converter after passing by a driving circuit. The converter disclosed by the invention not only can realize output voltage raising and reducing control, but also can improve a network side power factor, reduces the distortion factor of network entry current, has the advantages of simple structure, high system efficiency and the like and is convenient to control.

The invention discloses a voltage-equalizing and power-equalizing control method for a multi-module cascade solid-state transformer (SST). An SST power main circuit part applied in the method comprises an input stage, an intermediate stage and an output stage, wherein a common duty ratio control policy based on single-phase d-q vector control is adopted in the input stage so as to realize the unit power factor of an input end of an electric network; a control policy based on voltage feedforward and voltage feedback is introduced for each module in the intermediate stage, the voltage feedforward is used as a reference of the voltage feedback, and an error between the voltage feedforward and the voltage feedback is used as a reference of inner current loop of the module after being output by a voltage PI adjuster. The two control policies of the front stage and the intermediate stage interact so as to realize the functions of voltage and power equalization of each SST module, electrical network side unit power factor, high electrical network current sine degree, low switching tube voltage stress and the like.

Current transformer DC side voltage closed-loop control method of active power filter characterizes in a selective harmonic detect method, which will get two-phase coordinate system current after detecting the N time of harmonic active or reactive DC component and through delay compensated angle variable matrix, and to deduct DC side voltage adjust signal to make the compensate current signal contain a certain basic wave active current component, in which, adjust signal is the difference between the given value of the current transformer DC side capacitance voltage and feed back value of the side capacitance voltage adjusted by an adjuster.

The invention discloses a method for eliminating DC harmonic voltage for the grid-side converter of a double-fed wind power generator in the case of asymmetric power grid. The method adopts a phase-shift T/4 delay negative sequence fast separation method, which performs positive-negative sequence separation on the voltage and current of the three-phase power grid, wherein the positive-negative sequence separation method has simple calculation which only includes addition, subtraction, multiplication and division, fast response that the positive-negative sequence component can be worked out only in 5 m and small delay which facilitates the design of PI parameters. In order to obtain good control effect, the positive-negative double-dq current control with completely symmetric structure is adopted. Therefore, the positive-negative sequence current instructions are both DC components and the PI regulator can realize floating control.

The invention provides a grid power quality control system and method based on a unified power quality conditioner. The system comprises a series MMC, a parallel MMC and a control circuit. The series MMC and the parallel MMC form a unified power quality conditioner (UPQC) topological structure based on MMC, and are connected to a grid side and a load side through a transformer respectively. The method comprises the following steps: carrying out transformation on an MMC module under an abc stationary coordinate system to obtain a differential equation matrix model under a dq rotating coordinate system; obtaining small-signal models of the series MMC and the parallel MMC under the dq rotating coordinate system; utilizing the parallel MMC to output an offset current and stabilize DC side voltage; and utilizing the series MMC to output an offset voltage. A fundamental wave positive sequence voltage component and a fundamental wave positive sequence current component adopt a PI regulator, and other components adopt a PR regulator to realize non-static-error control, so that compensation is carried out not only for the cases of distortion, harmonic wave and reactive power and the like, but also for the cases of unbalance power source voltage and unbalance load, and the load is allowed to obtain reliable power supply.

The invention relates to a system and a method for performing weakening magnetism speed adjustment on a permanent magnet synchronous motor. The system comprises a current feedback computation module, a current loop PI adjustor module, a transformation output module, an advance angle computation module and a torque list searching module, wherein the advance angle computation module computes an advance angle theta lead according to a d axis voltage reference value Vd and a q axis voltage reference value Vq; the torque list searching module converts the q axis voltage reference value Vq to a torque value T, and searches a real q axis current value Iq in the torque list according to the advance angle theta lead and the torque value T; and a real q axis reference voltage instruction V q-real is obtained by conversion. According to the system and the method, the weakening magnetism speed adjustment can be performed on the permanent magnet synchronous motor conveniently by acquiring the torque list of a torque-current relation and searching the torque list according to the computed advance angle, the torque output capability of the motor is used to the greatest extent, and the problem that a current instruction is not accurate due to change of a torque-current coefficient is solved.

The invention discloses a grid-connected inverter for low-frequency current ripple output restraining of a fuel cell and a control device. The grid-connected inverter comprises the fuel cell FC, a boosting converter, a full bridge inverter and an LCL filter. The control device comprises a voltage sensor, a current sensor and a DSP digital controller. The boosting converter comprises an inverse-current-preventing diode, an input filtering capacitor Cin, a filtering inductor LB, an electric MOSFET and an output capacitor CDC. The full bridge inverter comprises four electric MOSFETs. The LCL filter comprises a capacitor C1 and two inductors L1 and L2. The DSP digital controller comprises a proportioner, a phase-locked loop, a subtracter, a PI adjuster, a multiplying unit, a summator, a signal generator, a comparer and a phase inverter. By establishing the boosting converter, energy decoupling on an input side and an output side is achieved, the fact that currents on the input side do not contain low-frequency ripples is guaranteed, the manufacturing cost of the grid-connected inverter is lowered, power conversion efficiency is improved, and an electric energy converting device suitable for fuel battery power generation is achieved.

The invention discloses a self-adapting resonance control method for transmitting non-contact electric energy, which is characterized by obtaining a phase difference by detecting and calculating the voltage and current outputted by a non-contact electric energy transmitting system contravariant mechanism, and adjusting the driving frequency of the inverter by outputting the electric energy to a PI adjustor and an oscillating element. After a transient state process, the phase difference of the voltage and current outputted by the inverter is zero, thus achieving self-adapting resonance control of circuits. The method guarantees separability between the receiving mechanism and the transmitting mechanism of the system only by detecting the voltage and current outputted by the contravariant mechanism, with the self-adapting resonance control function completely achieved by hardware circuits, while complicated control algorithm is not required. The method not only has self-adapting control capability on load change, but also has adjustment actions to the parameter variations of all the components after the output of the contravariant mechanism; besides, the method has the advantages of guaranteeing the system always works under a resonance condition, ensuring the output power and transmission efficiency reach the maximum value, and promoting the practicability process of the transmission technology of the non-contact electric energy.

The invention discloses a load disturbance compensation device of a permanent magnet synchronous motor. The load disturbance compensation device comprises a load moment recognition sliding-mode observer and the like. The permanent magnet synchronous motor is connected with a PARK conversion module, a PARK inverse transformation module, a velocity calculation module and a CLARK conversion module respectively. The velocity calculation module is both connected with a first summator and the load moment recognition sliding-mode observer. The first summator and a second summator are both connected with a speed ring PI regulator. The CLARK conversion module is connected with the PARK inverse transformation module. The PARK inverse transformation module is connected with the load moment recognition sliding-mode observer, a fourth summator and a third summator. The load moment recognition sliding-mode observer is connected with a load moment recognition value feed-forward compensation factor unit. The load moment recognition value feed-forward compensation factor unit is connected with the second summator. The second summator is connected with the fourth summator. The fourth summator is connected with an electric current loop PI regulator. The third summator is connected with the electric current loop PI regulator. The electric current loop PI regulator is connected with the PARK conversion module. The PARK conversion module is connected with a space vector modulation module, the space vector modulation module is connected with a rectification/three-phase inverter module, and the rectification/three-phase inverter module controls the permanent magnet synchronous motor to operate.

The invention discloses a STATCOM (static synchronous compensator) control system adopting a droop control strategy and a control method thereof. The STATCOM control system adopting the droop control strategy comprises a direct-current side capacitor, a three-phase inverter bridge and an inductance-capacitance filter, wherein the direct-current side capacitor and the three-phase inverter bridge are connected in parallel and then connected with the inductance-capacitance filter, and the inductance-capacitance filter is connected to a PCC (Point of Common Coupling) of a power grid by a three-phase switch K through a coupling transformer T. The control method disclosed by the invention comprises the steps of real-time signal collection, computation of active power reference value P*, computation of reactive power reference value Q*, computation of frequency reference value omega* and voltage modulation amplitude reference value E*, computation of phase reference value Delta* and computation of voltage modulation signals; and only one PI (proportional integral) regulator and two droop control coefficients need to be regulated, thus the whole control method is easy to realize, and further the power system can better supply power to users safely, excellently and economically.

The invention relates to a low-speed and zero-speed rotor position observation method and a low-speed and zero-speed rotor position observation device during fault-tolerant operation of a synchronous motor. The low-speed and zero-speed rotor position observation method during fault-tolerant operation of the synchronous motor is characterized in that: high frequency sine pulse voltage with fixed frequency is applied at a two-phase working winding end at partial time intervals, and the working winding generates corresponding high frequency current; and the high frequency current is synchronously acquired by a band-pass filter, a rotor position angle observation error function is calculated through links such as a multiplier, a low pass filter, an adder, a coordinate rotation transformation and the like, a value of the error function is sent to a proportional-integral (PI) regulator, and an observation value of the rotor position angle is output by the PI regulator. The invention is favorable for accurately observing the rotor position during the fault-tolerant operation of a three-phase salient pole synchronous motor under the condition that one phase of stator winding is open-circuit.

The invention relates to a grid connected inverter control method based on hysteresis modulation under the unbalanced grid voltage condition. The control method comprises that the voltage of a dc bus is detected, and a reference active power value is calculated via a PI (Proportion Integration) regulator; the positive sequence components and the negative sequence components of the grid voltage under a two-phase rotating coordinate system are obtained by processing three phases of detected grid voltages via coordinate conversion and positive/negative sequence component decomposition; three phases of instantaneous reference-current values are obtained from the reference active power value and the positive and negative sequence components of the grid voltage via calculation, coordinate conversion and the like; and finally, the three phases of instantaneous reference-current values are compared with three phases of practical current values, a certain hysteresis width is set, and driving pulses are emitted in a hysteresis control principle. The control method requires no parameters of grid connected filtering reactors, and only includes the PI regulator, thereby providing convenience for construction realization; and under the unbalanced grid voltage condition, the stability of instantaneous grid power can be effectively ensured, the voltage fluctuation of the dc bus can be lowered, and the stability of the grid connected inverters is improved.

The present invention relates to a method for correcting the phase error of the position signal of the no-position transducer brushless DC motor, which belongs to the method for correcting the phase error of the position signal of brushless DC motor. The correcting method controls a first afterflow current average value of the afterflow part in the 60 degree non-conductive interval after the negative 120 degree conductive interval of the electric motor phase winding same to a second afterflow current average value of the afterflow part in the 60 degree non-conductive working interval after the positive interval of the electric motor phase winding, to realize the phase error compensation of the position signal of the no-position transducer brushless DC motor. The specific method is measuring respectively the current average values of the two currents of the first current and the second current, inputting the deviation value of the average value of the two afterflow currents of the first and the second afterflow current as the feedback quantity to the PI regulator, and regulating the average value of the first current afterflow current equal to the average value of the second current afterflow current through the PI regulator. The correcting method can automatically correct the phase error of the position signal of the no-position transducer brushless DC motor, the realization is easy and the real-time property to the phase error of the position error is good.

A control method for a high-voltage direct-current flexible system for supplying power to a passive network includes: arranging a rectifier controller at the head end of a direct-current transmission line of the high-voltage direct-current flexible system, performing constant direct-current voltage control for a VSC (voltage source converter)-rectifier on the alternating-current system side, arranging a VSC-inverter controller at the tail end of the direct-current transmission line, and performing constant direct-current voltage control for the a VSC-inverter. A double closed-loop vector control policy is used for VSC-rectifier constant direct-current voltage control, fuzzy PI (proportional integral) control is used for an outer voltage loop, and current decoupling control is used for an inner voltage loop, so that active power and reactive power are controlled independently. The method avoids complicated offline parameter adjustment of a traditional PI adjustor and is capable of performing online PI parameter adjustment according to changes of the system running state and high in adaptive adjustment capability, the system is higher in response speed and control precision for various interferences and failures, and anti-interference capability and dynamic and steady-state performances of the system are improved.

The invention relates to an aerial three-level electric excitation motor starting control method and an aerial three-level electric excitation motor starting control device. The method comprises the following steps of: determining the controller output voltage vector in the mode of directly controlling the module value of the voltage vector and an included angle between the voltage vector and a main generator rotor, transmitting a switching signal of a three-phase full-bridge inverter in a mode of modulating a support vector machine (SVM) through a space vector, controlling the inverter to drive the main generator, and realizing the starting function of the three-level electric excitation synchronous motor. The aerial three-level electric excitation motor starting control method has the advantages that 1) the control links are fewer, a speed ring PI regulator and a current ring PI regulator are independent, and the parameters are conveniently adjusted; 2) real-time state information of the system is not required, the acquired original information of the main generator can be processed by using a complicated filtering algorithm, the information has certain robustness on transient interference, and the control performance of the system can be effectively improved; and 3) control objectives are fewer, and the comprehensive control error caused by electromagnetic interference of an exciter on the main generator can be effectively reduced.