Current Space Vector Modulation Research Articles

Research on Commutation and Coordination Control Strategy of Excitation Power Supply Based on Bidirectional Reduced Matrix Converter for Ion Accelerator

The contribution of this paper is putting forward a kind of ion accelerator magnet excitation power supply with bidirectional reduced matrix converter (BRMC) as well as a coordination control strategy with bipolar current space vector modulation strategy, which is utilized to realize bidirectional power flow for a BRMC system to solve problems such as low input power factor, large input current harmonics and no bidirectional energy in the conventional ion accelerator magnet excitation power supply. Meanwhile, a hybrid commutation strategy combining the simplified three-step commutation with zero vector commutation was proposed to solve the commutation problem for a matrix-type first stage in BRMC. The feasibility and effectiveness of the proposed strategy, which can achieve bidirectional energy flow and safer commutation, have been verified by the experimental results.

Hybrid Modulation Strategy for Two-Stage Matrix Converter and its Application in Vector Control of Doubly Fed Induction Generator

A hybrid modulation strategy (HMS) for a two-stage matrix converter (TSMC) is presented in this paper. According to the variation of voltage transfer ratio, different combinations of modulation modes for rectifier-side converter (RSC) and inverter-side converter (ISC) of TSMC are adopted. Two different current space vector modulation methods are used for RSC to obtain maximum and minor DC voltages. The power loss of TSMC is reduced based on the minor DC voltage. In addition to the linear space vector modulation for ISC, an overmodulation method is presented in order to increase the voltage transfer ratio of TSMC. HMS ensures smooth switching between different modulation modes and makes the best use of the advantage of these modes. Finally, HMS is applied in the case where TSMC is used as an AC-excitation converter for doubly fed induction generator (DFIG) to achieve maximum power point tracking (MPPT). The simulation results confirm the accuracy and feasibility of HMS and the good performance of the MPPT operation of DFIG excited by TSMC.

A Bidirectional Single-Stage DC/AC Converter for Grid Connected Energy Storage Systems

In this paper, a unified control strategy using the current space vector modulation (CSVM) technique is proposed and applied to a bidirectional three-phase DC/AC converter. The operation of the converter changes with the direction of the power flow. In the charging mode, it works as a buck type rectifier; and during the discharging mode, it operates as a boost type inverter, which makes it suitable as an interface between high voltage AC grids and low voltage energy storage devices. This topology has the following advantages: high conversion efficiency, high power factor at the grid side, tight control of the charging current and fast transition between the charging and discharging modes. The operating principle of the mode analysis, the gate signal generation, the general control strategy and the transition from a constant current (CC) to a constant voltage (CV) in the charging mode are discussed. The proposed control strategy has been validated by simulations and experimental results obtained with a 1kW laboratory prototype using supercapacitors as an energy storage device.

AC/DC Matrix Converter With an Optimized Modulation Strategy for V2G Applications

To adapt the battery voltage and increase charging efficiency in vehicle to grid (V2G) systems, an ac/dc matrix converter topology is presented. Aim to solve the problem of relatively large charging current ripple in the classical current space vector modulation strategy, a sectional optimized modulation strategy, is proposed, which can reduce the charging current ripple within the whole output range. And the comparative analysis is carried out between them. A simple controller with active damping is briefly introduced; it can work at two charging modes: constant voltage charging and constant current charging. The simulation and experimental results demonstrate the validity and effectiveness of the proposed method.

Voltage control of current source inverters

The current source inverters may become direct competitors of the voltage source inverters thanks to the voltage control techniques. The paper proposes an improved voltage control technique for current source inverters, that chooses the current vectors relying on bang-bang controllers. This technique is compared to a well-established one using current space vector modulation and synchronous-frame proportional and integral controllers. The presented controller is explained and validated by means of off-line as well as real time simulations and experimental tests. The numerical results prove that the proposed control technique produces less distorted voltage waveforms in terms of total harmonic distortion and spectrum. According to the real-time simulations performed the proposed control technique is computationally less expensive than the benchmark. Finally, the experimental results obtained confirm the feasibility of the proposal.