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To keep the switch frequency constant and reduce the fluctuation of flux linkage and torque in traditional elevator drive direct torque control (DTC) system, a method of SVM-DTC based on reference flux linkage is used. Switching table and hysteresis controller in traditional DTC is replaced by flux linkage estimator and SVPWM modulation module. For the problems of complex control and harmonic interference...
Voltage-feedback Push-Pull DC-DC converter, namely VCPPDC-DC, is a dominant component of SMPS system, has rich dynamical characteristic. For revealing internal relation between stability and system circuit parameters, VCPPDC-DC was studied in details. According to practical closed-loop control logic, the general simulation model was set up by using the exact state equations. And the general discrete...
For Unified Power Quality Conditioner (UPQC) adopting traditional hysteresis control method, unstable switching frequency causes great switching loss, and voltage space vector control method leads to a serious interphase interference to three-phase three-wire systems. To solve these problems, a hysteresis tracking control method with constant switching frequency based on voltage space vector is proposed...
In the direct power control system of three-phase PWM rectifier, the control accuracy of active power and reactive power directly affects the whole system's performances. The DC side capacitor's mechanism on the DC side voltage is analyzed and the power feedforward control strategy based on the power mathematical model is researched in this paper, which can effectively restrain the DC side voltage...
Considering the disadvantages of traditional control strategy which is used on the motor energy feedback and grid-connected device parallel connecting on the DC side of AC-DC-AC frequency convertor, such as slow dynamic response and poor grid-connected power quality, a double closed-loop current feed forward decoupling control strategy with grid voltage sensor-less has been adopted. The method estimates...
Considering large volume, high cost and low reliability caused by the existence of mechanical sensor in the control system of permanent magnet synchronous motor(PMSM), this paper designed a speed observer instead of mechanical speed sensor based on sliding mode variable structure theory to realize speed sensor-less control of PMSM. Because accurate values of motor voltage and current were needed for...
To limit grid side harmonic and increase power factor of EV charger, A SVPWM based voltage-source rectifier (VSR) control method is presented in this paper. Basing on regular double-close-loop control strategy, Fuzzy-Pi control algorithm is adopted in the inner current loop besides traditional PI algorithm being used in outer voltage loop. By taking the double-close-loop fuzzy control method, the...
To extend the compensation ability of unified power quality conditioner (UPQC) and suppress the grid current fluctuation at the time of power regulation, a kind of improved UPQC topological structure is proposed. With advantages of high power density, large electrostatic capacity and long cycle life, super capacitors are combined with bidirectional DC/DC converter to compose the energy storage system...
Voltage-feedback BUCK converter, namely VCBUCK, which is the dominant component of SMPS system, have rich dynamical characteristic. For revealing internal relation between stability and system circuit parameters, VCBUCK in CCM was studied in details. According to practical closed-loop control logic, the general simulation model of difference or indifference in balance was set up by using the exact...
Traditional transformer in high-voltage power supplies has many disadvantages such as high turn's ratio, large volume and great design difficulties. Parallel resonant converters (PRCs) are widely used in high-voltage power supplies. A kind of high-voltage circuit topology can be formed by combining PRCs and voltage-doubler rectifier, which is called parallel resonant dual voltage converters (PRDVCs)...
In this paper, a small signal model of a novel ZVZCS FB-PWM DC/DC converter is built and analyzed. A double closed loop controller is employed: the inner loop is a PI controller and the outer loop is a fuzzy logic with integrator controller. The novel control strategy improves the performance of the converter greatly, such as stability, control precision and dynamic response. The dramatic feature...
In this paper, a small signal model of a novel ZVZCS FB-PWM DC/DC converter is built and analyzed. A double closed loop controller is employed: the inner loop is a PI controller and the outer loop is a fuzzy logic with integrator controller. The novel control strategy improves the performance of the converter greatly, such as stability, control precision and dynamic response. The dramatic feature...
This paper analyzes the electromagnetism in the stator slots of the motor using the software ANSYS for finite element analysis (FKA). A model of single slot is established and the value of the distributed inductance and the distributed capacitance of each turn in the slot can be calculated. After analyzing how the distributed parameters of the windings change with the different location of each turn,...
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