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This paper discusses the dead-time effect of dual bridge series resonant DC/DC converter (DBSRC). The phase-shift modulation is usually adopted in DBSRC. However, the phase-shift angle is usually small, and voltage polarity reversal (VPR) may occur in dead-time, which may deteriorate EMI/EMC and increase loss. This paper analyzes the commutation of DBSRC when VPR occurs and proposes a method to eliminate...
For the vacuum arc, the parameters of the interelectrode plasma have influences on the electrode process. It is necessary to obtain the parameters and characteristics of the plasma by simulating the plasma among the electrodes. In this paper, based on the analysis of the existing vacuum arc model, combined with the characteristics of vacuum arc fault under different interrupting conditions, the effects...
Output voltage of renewable energy resources, such as fuel and solar cells, varies widely with load and environmental condition, so a DC-DC converter should be suitable for wide input-voltage range application and be with low input ripple current. An integrated boost three-phase half-bridge converter is proposed. The boost and three-phase half-bridge converters are integrated to reduce number of switches...
This paper proposes a simple duty cycle modulated direct torque control (DDTC) for permanent magnet synchronous motors (PMSMs). DDTC sequentially output an active vector and a zero vector during each control period. The duty cycle of active vector is obtained using a duty cycle generator according to the torque error, which can avoid the complex calculation process associated with conventional DDTC...
In order to increase the efficiency of enterprise and reduce the grid load demand of large-scale renewable energy such as wind and solar energy in regional power grid system, Shapley value method has been proposed to analyze the cooperation game relationship between high energy-consuming customer and power system. Using the system dynamics method, an interaction analysis model for describing participation...
This paper proposes a method for high-resistance connection (HRC) fault severity detection in a permanent magnet synchronous machine (PMSM), which helps in determining the scheduled maintenance. The proposed method is based on the zero sequence voltage component (ZSVC) and the stator currents. The PMSM mode in abc stationary frame is presented. The relationship between the ZSVC, the stator currents...
Single-stage buck-boost gird-connected inverter is widely used in distributed generation systems because of low cost and high efficiency. However, shoot-through problem exists, so reliability of the system is reduced. In addition, output voltage of renewable energy resources varies widely with load and environmental condition, so voltage stress of switches is high in wide input-voltage range application...
This paper proposes a sensorless field-oriented control(FOC) strategy for Surface-mount Permanent Magnet Synchronous Motor(SPMSM). Firstly, a rotor flux estimation method with a high pass filter is introduced. Secondly, the basic principle of PLL and PI parameters tuning method derivation are demonstrated. And then, the compensation method for the phase shift caused by the high pass filter has been...
Model predictive control is a kind of control method based on parameter model. However, in the actual system, the parameters of the motor may deviate from the parameters in the model due to the influence of various objective factors, leading to deterioration of the control performance. In this paper, a strong parameters robustness model predictive current control (MPCC) method for permanent-magnet...
Recent years, multilevel inverters have become more attractive for researchers due to low total harmonic distortion (THD) in the output voltage and low electromagnetic interference (EMI). This paper proposes a three-phase cascaded H-bridge quasi-switched-boost inverter (CHB-qSBI). The advantages of the proposed inverter are as follows: buck-boost voltage with single stage power conversion, reduced...
In this paper, a fluid-thermal coupled finite element model is established to calculate the temperature field of dry type air core reactor, the inner structure of reactor is built both considering the calculation accuracy and computation time. According to simulation results, the detailed temperature distribution regularity are given both with and without the rain cover, and it can be achieved that...
In order to reduce the ripple of DC-link voltage and capacitor current, this paper presents a method to select suitable capacitance for the rectifier (full-wave controlled) and inverter. Meanwhile, a braking unit is developed to prevent the overvoltage of DC bus. The impact of the length of cable, connected between the braking unit and the inverter, is researched from a mathematical point of view...
Linear flux switching motor with segmented secondary (LFSMSS) is characterized by two kinds of windings, i.e. the DC field windings and AC armature windings, which are distributed alternately on the mover. LFSMSS is vulnerable to large force ripple. This paper investigates the influence of two design techniques (dummy slot and auxiliary tooth) on the force ripple of LFSMSS. In addition, the simulation...
With the rapid development of the power grid and the increase of power demand, the voltage level of the substation is improving rapidly. The noise caused by the transformer becomes a serious problem because it affects the health of the surrounding residents. In this paper, the noise of 1000kV transformer in Shanxi is measured and analyzed. The results show that the transformer noise has low frequency...
The semi-controlled open-winding permanent magnet synchronous generation system with a common dc bus provides a flowing path for zero sequence current, which will decrease the efficiency of the whole control system. To solve zero-sequence current of the semi-controlled open winding PMSG system, a model predictive current control (MPCC) method is proposed based on the analysis of the working principle...
This, paper proposes a method to eliminate the dc component in the measured three-phase grid voltage as the input signals of phase-locked loop (PLL). The dc component in the input signals of PLL causes a low-frequency oscillation of grid frequency. The dc component elimination can be achieved by replacing the integrator in the second-order generalized integrator (SOGI) with a differentiator, named...
In this paper, an advanced droop control using a multinomial model for operating the parallel-connected uninterruptible power supply (UPS) inverters is proposed. To control the parallel inverters without any physical communications, the control method using a P/Q droops is conventionally used. The conventional method droops voltage and frequency using the monomial model. In conventional droop control,...
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