Current Control Type Research Articles

Electrodeposited Co-P alloy and composite coatings: A review of progress towards replacement of conventional hard chromium deposits

Hard chromium coatings have attracted much attention due to their strong tribological and corrosion performance. There is a global need to replace such coatings in industrial applications owing to technical problems, environmental concerns and legislation. Co-P electrodeposits are a promising alternative to hard chromium in a variety of engineering applications due to their appreciable microhardness and high corrosion resistance . Attractive magnetic, tribomechanical and electrical properties are evident together with excellent thermal stability. Environmentally acceptable process conditions may be used which allow controlled deposition on diverse workpieces across a wide scale. This review provides an overview of the influence of operational parameters, including type of current control, electrolyte composition, pH, current density and electrolyte agitation on the physicochemical and mechanical characteristics of the deposits. The incorporation of ceramic particles into Co-P electrodeposits to produce tailored composite coatings is also considered. An insight is given into the development of next generation alloy and composite deposits to replace hard chromium deposits from acidic Cr(VI) baths. Diverse applications for Co-P electrodeposits are considered and topics deserving further R & D are highlighted. • A concise overview of Co-P alloy electrodeposits is provided. • The most common types of bath used for Co-P electrodeposition are considered. • The influence of operating conditions on properties of deposits is addressed. • Effects of included particles on deposit characteristics are comprehensively discussed. • Potential applications of Co-P films are highlighted.

Physical Interpretations of Grid Voltage Full Feedforward for Grid-Tied Inverter

Influence on an injected current arising from grid voltage is a noticeable issue in the design of grid-tied inverter, especially under low control gain or low power command conditions. The grid voltage full feedforward strategy is a widely used strategy to solve this problem, whereas the physical meanings of the full feedforward items are unclear. In this brief, the full feedforward of the direct current control type LCL-filter inverter and indirect current control type LCCL-filter inverter was reviewed from the circuit and control perspectives. The full feedforward items were rephrased. The new interpretations indicate that the full feedforward strategy is physically rational and complete.

Virtual Synchronous Generator Control with Double Decoupled Synchronous Reference Frame for Single-Phase Inverter

We have proposed the Virtual Synchronous Generator control (VSG control) and have tested it using the demonstration equipment [1]. By using the VSG control, three-phase inverters of current control type are able to run both in grid-connecting operation and in grid-disconnecting operation. Furthermore, in order to control a single-phase inverter like a three-phase inverter using the VSG control, we have applied the technique called “Double Decoupled Synchronous Reference Frame” (DDSRF). In this paper, we will show you the simulation results and experimental results of the single-phase inverter using the VSG control with DDSRF.

Current Control Type Power Distribution Algorithm of Indirect Fuel Cell Hybrid Vehicle

An indirect fuel cell hybrid vehicle test bench is established for validating the control algorithm. The fuel cell output voltage is boosted through DC / DC converter. DC / DC converter positive and negative outputs are respectively connected with lithium battery sets positive and negative outputs. DC/DC converter output current and output power are regulated by the DC/DC converter main controller via CAN bus. So the fuel cell output power is regulated. Different fuel cell output power and motor input power proportional coefficient is adopted according to different lithium battery sets SOC (state of charge). The power distribution algorithm between fuel cell and Lithium battery sets is validated in tests.

LCL Filter with Active Damping using PI and SSI Regulators in Synchronous Rotating Reference Frame Current Controller for DSTATCOM

Abstract This article proposes a distribution static compensator (DSTATCOM) with interface LCL (inductor-capacitor-inductor) filter for load compensation in three-phase four-wire distribution system. DSTATCOM, consisting of voltage source inverter (VSI), is connected in parallel to the load and injects currents corresponding to load reactive, harmonic powers. But this injected current consists of unnecessary high-frequency switching ripple generated by VSI. This LCL filter has superior switching ripple attenuation capability compared to L filter. Moreover, this can be achieved with small value of overall LCL filter inductance than L filter. Thus providing high slew rate for output current to track the desired reference current closely, reducing voltage drop across it, as well as cost and size of filter. However, one major concern with LCL filter is its resonating frequency (determined from its L, C, L values), which can create high-resonance oscillating currents and results in improper load compensation. Therefore, in this study, proper design of LCL filter with high switching ripple attenuation and a current controller with proportional integral (PI) plus harmonic compensation (HC) regulators along with active damping feature of LCL filter in synchronous rotating reference (dq0) frame are presented. HC regulator minimizes the steady-state error in the non-sinusoidal filter currents (fundamental and harmonic) which are tracked by the VSI. Active damping feature (obtained by capacitor current feedback control of LCL filter) is used to overcome resonance oscillations and provides proper control, operation of DSTATCOM under steady-state and dynamic load conditions. Stability studies for designed LCL filter and current controller using Bode and root locus plots are also performed and presented. Extensive simulation study, to understand the compensation performance of LCL filter DSTATCOM with two types of current controllers (PI and PI plus HC) under steady-state and dynamic load conditions, is carried out in PSCAD simulator and the corresponding results along with THDs of various parameters are presented.

Enhanced current control of high-speed PM machine drives through the use of flux controllers

This paper compares various types of current controllers, including a novel method based on flux control. A proportional integral (PI) control method is used initially, to control the current in a high-speed permanent-magnet synchronous machine. The performance of this simple PI loop is presented, Various improvements to the PI controller are investigated, and the change in performance examined. A new current control scheme based on a flux-linkage model of the machine is introduced. The performance of the model-based control is demonstrated and compared with the performance of the PI current controller. Factors affecting the accuracy of the model-based control are given. By incorporating these factors into the model, the performance of the flux controller is further enhanced.

Position Control Using a Two-Phase Induction Motor(Compound Control Consisting of Neuro-Adaptive Control and Vector Control).

In this report, the position control method using a two-phase induction motor is investigated. The position control system consists of neuro-adaptive control and slip frequency control type vector control. The vector control was implemented with an electric current control type PWM inverter and the vector computation algorithm. The experiments were carried out, and the usefulness of the present control method was confirmed. Furthermore, the experimental results by the neuro-adaptive control and the vector control was compared to the experimental results by the two-degree-of-freedom control and the vector control.

Completely digital position feedback control for synchronous servodrives

A completely digital control concept for a synchronous servodrive is presented. The hardware consists of a PWM (pulse-width-modulated) inverter and a microcontroller with peripheral components for state value measurements and set value output. The derivation of a mathematical model of the PM synchronous servodrive is shown. A novel cascaded state feedback controller, which consists of a position state feedback controller with an inner current-control loop, is introduced. Two different types of current controllers are compared. >

One-dimensional calculation of thyristor forward voltages and holding currents

One-dimensional numerical analysis of complete semiconductor device equations is applied to the p-n-p-n four layer structure with an arbitrary impurity doping profile and arbitrary carrier lifetimes, to calculate the thyristor DC forward voltages and the holding current. In the beginning, a numerical method of the current-control type is presented, with discussion about the convergence of the iterative process involved. Then a set of standard numerical values is given to the parameters to describe the impurity doping condition. Computation results are demonstrated for a variety of carrier lifetimes and current densities. Endeavor will be made to understand basic device physics through the computed carrier densities, electric fields, potentials and currents. The computation results also include the static current vs voltage characteristics, which are immediately concerned with the actual design and fabrication of thyristors. Specifically for the design of high speed thyristors, a preferable condition is provided by keeping lifetimes in the shorter base to a high value and those in the longer base to a low value.