Repair based Constraint Handling Techniques for Microgrid Sizing and Energy Management Optimisation


Microgrid sizing and energy management system (EMS) optimisation problems have conflicting objectives while subjected to complex constraints. These problems are usually solved by using meta-heuristic algorithms, which are originally developed to solve unconstrained problems. Therefore, appropriate constraint handling technique (CHT) must be employed to solve constrained problems. It appears that use of CHTs in these problems is rare. This study proposes using two types of repair-based penalty approaches to solve a microgrid sizing and EMS problem. Cuckoo search algorithm is employed to solve the multi-objective optimisation problem, which minimises the levilised cost of electricity (LCOE) and dump load, while maximising the reliability of power supply. A case study based on the Westray Island standalone microgrid in Scotland is conducted to compare the effectiveness of the repair approaches, in terms of the objective function values and convergence speed.

Keywords: Constraint handling, Energy management system, Microgrid, Renewables, Repair methods, Sizing

Impact of Wave Energy Integration on Sizing and Energy Management of a Microgrid: Case study


This paper investigates the impact of integrating a wave energy converter (WEC) on sizing the battery and energy management of a microgrid utilising wind, solar and diesel generator at the generation side. A sequential co-optimisation model for sizing and energy management is proposed to minimise the levilised cost of electricity (LCOE) and dump load, while maximising the reliability of power supply. Cuckoo search algorithm is employed to solve the multi-objective optimisation problem. Moreover, a repair-based penalty approach is integrated for effective constraint handling. The Westray Island standalone microgrid in Scotland is considered as a case study. Annual hourly weather data of Westray Island and the demand profile are used to simulate the system in MATLAB environment. The numerical results show that the battery capacity is reduced when WEC is integrated in the microgrid. However, with the WEC integration, the LECO slightly increases with increased reliability of the power supply.

Keywords: Constraint handling, Energy management system, Microgrid, Sizing, Wave energy



New Concept for Current-Impressed Wireless Power Transfer to Multiple Independent Stainless-Steel-Enclosed Linear Actuator Tool Carriages

Linear actuators in, e.g., the food-processing or pharmaceutical industries are enclosed in stainless steel (SS) to facilitate thorough cleaning and disinfection.
Efficient wireless power transfer (WPT) through these SS enclosures realizes wireless electrification tool carriages and eliminates bulky, hard-to-clean power cables and cable carrier assemblies. This digest proposes a novel concept for current-impressed WPT through SS to multiple independent loads. The proposed method is thoroughly analyzed, optimized, verified in simulations, and compared against conventional voltage-impressed and current-impressed approaches, showing a clear complexity reduction and significant efficiency improvements, respectively. The final paper will contain a detailed experimental characterization of the proposed concept implemented in an industry-like, SS-enclosed linear actuator demonstrator system with two independent 100 W loads.

Numerical Optimal Control Strategy for Series Tuned IPT Systems

1. Proposed a novel numerical approach for achieving optimal operation of series-series compensated IPT systems based on optimal control strategy.

2. In this approach, the analytical ZVS condition is converted into an equivalent numerically defined ZVS condition, while the other conditions related to load impedance matching and the minimum secondary reactance remain in analytical form.

3. To overcome the problems caused by the high nonlinearity due to numerically defined conditions, a numerical solving method is proposed.

κ-δ Pareto Front of Two-Coil Wireless Power Transfer Systems for Electric Vehicles with Buried and Flush Ground Primary Side Mounting

Flush ground and buried primary sides are a blank space in the latest SAE J2954. This paper contributes to the investigation on the maximum achievable coupling coefficient κ of the secondary sides in a common single primary single secondary side coil arrangement. By introducing a κ-δ Pareto Front, it is shown that for flush ground and buried primary sides remarkable degradation cannot be avoided ultimately leading to additional losses in the overall system operation.

A Dual-Active Single-Ended Wireless V2H System with Self-Synchronized Phase-Difference Control Method

This paper discusses the bidirectional Wireless Power Transfer (WPT) device for vehicle-to-house (V2H). It makes use of a simple, compact single-ended converter and a phase-difference control mechanism that is self-synchronized. This paper proposes a way whereby phase difference control could well be self-contained just on the slave side without mutual communication. This method allows for high-power wireless transmission despite the low coupling coefficient between the transfer coils. The phase difference and transmission power can be altered by changing the MOSFET conduction time on one side without synchronizing the phases on both sides.

Ground Assembly Coil Design Routine for Dynamic Wireless Power Transfer

In this paper, a design routine for the ground assembly (GA) of a Dynamic Wireless Power Transfer (DWPT)
system is presented. Depending on a predetermined vehicle assembly (VA), the method returns the optimal GA
coil geometry as well as the control strategy to power the coils and the positioning of the segmented DWPT lane.
In addition to the general optimization objectives costs and efficiency, the output power fluctuation along the
road is taken into consideration.

A Secondary-Side Resonant LLC converter for Reducing Resonance Voltage with Boost Mode Operation Using Resonance Including Current Doubler Rectifier

Isolated DC-DC converters in data centers are now required to have a high step-down ratio and be suitable for high-power applications. As such DC-DC converters, LLC resonant converters have been attracting attention. However, the LLC resonant converter generates a large resonance voltage at the resonator, so the resonance inductor and resonance capacitor must be large in size. Recently, a previous study proposed a secondary-side resonance LLC converter to reduce the resonant voltages of the passive components. Nevertheless, this LLC converter requires a resonant capacitor in parallel with the rectifier to achieve boost mode operation, which complicates the circuit operation and design. Therefore, we have considered the use of the magnetizing inductance of the coupled inductor of the current doubler rectifier as a method to realize the boost mode operation. In this paper, we propose a new method of boost mode operation for LLC resonant converter using secondary-side resonance and the current doubler rectifier.