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This paper has proposed a sensor-less control strategy for direct-driven permanent magnet synchronous generator (PMSG). Synchronous rotating frame phase lock loop (SRF-PLL) that employs model based back elector-motive force (EMF) estimation is utilized to derive rotor position angle and speed. To steadily achieve the sensor-less vector control, a first order compensator is applied in cascade with...
Obviously, tracking harmonic current fast and precisely is one of the keys to design the APF. This paper researches the control method of three-level active power filters. The conventional current state feedback decoupling PI control is analyzed in this paper in detail. This paper pointes out the limitation of the conventional PI conditioner in the research field of APF and presents a novel PI control...
In pulsed power system, capacitor charging power supplies (CCPS) are normally employed to provide energy for capacitor. To meet the request of reducing input power rate, this paper focuses on the series-parallel resonant CCPS. In this paper, the electric characteristic of series-parallel resonant converters is analyzed in detail. Based on theoretical analysis, the resonant parameters design method...
This paper main focus on the 3-D modulation scheme and neutral-point unbalance problem of 3-level 3-leg converter for active power filters. The neutral point unbalance problem is a key issue for this topology based APFs. To date there hasn't any perfect 3-D modulation solutions to tackle with neutral point unbalance problem well. In this paper, a detailed discussion on this issue is carried out. The...
In the power system in marine vehicles, there are many fault diagnosis and maintenance info, including the generators, the transformers, the motors and the converter/inverters. And, there are so many methods to cope with the above problems separately. In this paper, the whole power system is considered as a load, or as IPS, the three-dimension analysis of the IPS, the process of the fault diagnosis...
Effective fault detection and diagnosis (FDD) is especially important for some special applications, such as Navy ships operating in hostile environments. So far, FDD for nonlinear systems has not been fully explored. This paper makes an effort to fill the gap by extending an existing monitor architecture and a series of algorithms for FDD of permanent magnet synchronous motors (PMSM). A fault model...
This paper will present an improved cascade multilevel converter that is the series-connection of a diode-clamp converter and several H-bridge converters with equal dc bus voltage. According to this topology, a hybrid modulation method which incorporates square-wave synthesis in conjunction with unipolar triangle carried-based PWM method is illustrated. By the hybrid control scheme, higher voltage...
By defining power electronic load cell (PEL cell) and adopting different control strategies, the application of power electronic load for both AC and DC source is presented in this paper. A unified power electronic load is proposed which is composed of three basic PEL cells. Improved repetitive control is proposed to improve the dynamic performance of the system. Theoretical analysis and simulation...
A novel power electronic load (PEL) is introduced in this paper. This equipment can simulate R,L,C load as well as non-linear load. Furthermore, it can recycle the energy back to grid. Topology for single phase AC PEL, three-phase AC PEL, and DC PEL are presented firstly. Based on disadvantages of repetitive controller, an improved repetitive controller is presented to improve the dynamic performance...
Due to the difficulty of handling nonlinear loads for traditional active power filter(APF) with two-level inverter in high voltage high power grid, this paper researches three-level active power filters. This paper presents an improved repetitive scheme to control the shape of output current waveform. The design process of each part in the repetitive controller is presented. Q(z) is designed as a...
Three-level NPC inverter has been put into practical use for years especially in high voltage high power grid. This paper researches three-level active power filters(APF). In this paper the mathematical model in d-q coordinates is presented for 3-phase 3-wire APFs. The dead-beat control scheme is obtained by using the state equations. Canceling the delay of one sampling period and providing the predictive...
In this paper a deadbeat control system with a novel 3-dimension (3-D) space vector modulation scheme for 3-phase 4-wire tri-level three-leg Active Power Filter (APF) is proposed. To improve the compensation effect a repetitive harmonic predictor is utilized to predict the harmonic current and a state observer is used to estimate the output currents of the APF at the sampling instants in the deadbeat...
This paper presents a novel digital control scheme for single-phase PWM rectifier for reducing AC-side harmonic currents and improving power factor. The proposed inner current loop is a predictive controller with a plug-in repetitive learning controller, it can achieve zero tracking error and simultaneously hold a fast response with the DC load disturbance. A digital notch filter is added to the outer...
A novel static compensator (STATCOM) is proposed in this paper. The new STATCOM is constructed by a hybrid topology cascading a neutral-point-clamped (NPC) inverter and several identical H-bridge inverters. With the novel topology consisting of a same DC bus voltage but different structure modules, the realization of a multilevel converter using a hybrid approach that involves higher voltage devices...
This paper presents two current control techniques for single-phase voltage-source PWM rectifiers. The PI controller is compared with the resonant controller. In addition, a compensating method to eliminate input current distortion caused by supply voltage harmonics for the resonant control is proposed. Finally, the differences in the performance of the two controllers in a single-phase PWM rectifier...
This paper proposes a direct power control (DPC) strategy employed for the neutral-point-clamped (NPC) three-level PWM rectifier. Mathematic model of NPC three-level rectifier is conducted firstly as a theoretical base. This topology generates a higher number of output voltage levels, increasing the flexibility for selecting an appropriate voltage vector. The direct instantaneous power control technique...
Due to the limitation of voltage capability and current capability of power devices, it is very difficult to handle nonlinear loads for traditional active power filters(APF) with two-level inverter in high voltage high power grid. Three-level NPC inverter has been put into practical use for years especially in high voltage high power grid. The application of such converter to APFs is hindered by the...
The paper present a new test equipment for single-phase ac power source tests named PEL(power electronic load), the proposed architecture consists of two power stages such as input AC-DC imitation converter to imitate various loads and the output grid-connection converter to send back the recycling energy to the utility grid. In PEL, the controllable imitation converter enlarges the load bound that...
PWM VSR is widely used in different power equipments to depress the harmonic of the ac-side current and improve power factor. In this paper, the operating principle and the control scheme of the single phase PWM rectifiers are introduced firstly, P(proportion) controller is used in the ac current control loop to ensure the ac-side current track the current reference fast, the related equations are...
To reduce the flux and torque ripples, the paper modifies the synthesizing technique, proposes ldquo24 vectorsrdquo method and ldquo24 vectors + altering modulation indexrdquo method, which can be implemented to achieve favorable stator flux linkage and torque control performance in three-level induction motor direct torque control (DTC) system. The improvement of motor performance by proposed schemes...
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