This paper proposes a secondary-stage three-port integrated dual input dc-dc converter for on-board charging applications, designed to interface seamlessly with a half-bridge power factor correction (PFC) stage. The proposed topology possesses inherent voltage-balancing capability, effectively eliminating capacitor voltage mismatch issues in the half-bridge PFC stage. A detailed analysis of the operating modes, based upon link current characteristics, is presented along with the boundary conditions governing mode transitions. A pulse width modulation (PWM) control strategy for the three-port converter including power sharing capability from the input sources has been proposed. The digital implementation of the closed loop control strategy has been detailed. The operation of the converter is validated through simulation results for various conditions using PLECS simulation software. Experimental results from a 160 W laboratory prototype further validate the converter’s performance and confirm its suitability for high-efficiency OBC systems.

In bipolar dc distribution systems, voltage balancers play a crucial role in maintaining pole voltage balance. Instead of employing dedicated balancer circuits, which add extra switches and passive components. In recent designs, the voltage-balancing function is integrated directly into the converter structure, enabling simultaneous power processing and pole-voltage balancing. This offers a compact, cost-effective, and multifunctional solution for bipolar dc lines. This work presents an optimized PWM scheme for Integrated Three Port Converter (ITPC) that minimizes system losses while maintaining stable converter operation. The proposed scheme effectively balances pole voltages without sacrificing regulation accuracy or power transfer capability. The concept is validated through detailed simulation and experimental hardware results, showing approximately 15-20 % reduction in total losses and about 3-5 % improvement in overall efficiency compared to conventional modulation methods. The proposed PWM scheme provides a practical solution for high-efficiency operation of ITPC interfaced to bipolar dc distribution systems.

Battery powered consumer electronic applications such as lightweight electric vehicles, uninterrupted power supplies, and lightning systems often use a single series-connected string at lower power ratings. The overall performance of such systems during both charging and powering is restricted in case the individual battery units have dissimilar characteristics. In order to reduce such mismatches, in addition to the power processing interface, battery management systems are used to maintain consistency among these different units through voltage/charge balancing techniques. This paper proposes a unified solution using an integrated three-port DC-DC power electronic converter interface that can perform both power processing and charge equalization tasks when interfaced with single battery string inputs. The charge-balancing port of the converter is reconfigurable using an electro-mechanical relay that can switch between the battery terminals to reduce the stress upon the weaker batteries. The modeling, analysis, and control development of the proposed converter are presented in this work. The proposed theory of operation has been validated using simulation and experimental results for a 500 W four-battery system intended for low power consumer electronics and light-weight electric vehicle applications.

This paper presents a High-Frequency (HF) QuasiResonant (QR) Zero-Voltage Switching (ZVS) Boost Converter that employs a Switched Capacitor Bank (SCB) to dynamically tune the LC resonant tank and regulate the output voltage. By selectively activating different capacitance values, the converter achieves different voltage levels while maintaining ZVS across a certain load range. Operating in the MHz range, the proposed converter enables efficient soft-switching without compromising performance. A detailed analysis is conducted to evaluate the impact of parasitic elements on ZVS and output regulation. Simulation and experimental results demonstrate the effectiveness of the SCB in achieving tunable output control and preserving ZVS, with an overall measured efficiency of approximately 84%.

Multi-port DC-DC converters, including the proposed design, are pivotal for hybrid-source systems and renewable energy integration, where effective power flow management is a critical challenge. This study explores the implementation of Continuous Control Set Model Predictive Control (CCSMPC) to enhance the performance of Single Input Multiple Output (SIMO) DC-DC converters. The control scheme has been executed using the Integrated Dual Output Converter (IDOC) which is a topology capable of step-up and step-down voltage regulation. The MPC algorithm optimizes real-time control using discretizing system models, incorporating cost functions, and adjusting switching sequences for stability and efficiency. Simulation results are validated in MATLAB/SIMULINK and reflect the design’s superior transient response and dynamic performance.

The paper presents the modeling, control, and optimization of a solar-powered water pumping system using Model Predictive Control (MPC). A Single-Input Dual-Output (SIDO) DC - DC converter serves as an interface between the Solar Photovoltaic (PV) array and a separately excited DC motor. The Perturb and Observe (P&O) algorithm is used for Maximum Power Point Tracking (MPPT) due to its simplicity and efficiency in extracting maximum power under varying solar conditions. This study explores MPC to enhance the performance of Single-Input Multiple Output (SIMO) DC-DC converters. The proposed system enables single-stage operation, regulating inductor currents, controlling motor speed, and supplying armature and field voltages using a single converter. MPC optimizes real-time control by discretizing system models, defining cost functions, and adjusting switching sequences for improved stability and efficiency. Simulation results validate the system's superior transient response and dynamic performance in solar powered motor drive applications.

Reconfigurable On-board power electronic converters utilize the same set of power devices during charging and propulsion modes of operation. The circuit configuration in each of the operating modes are enabled through appropriate positioning of mechanical relays. For safe-operation of the converter, it is essential to validate the relay transition and its positioning prior to start of operation in any particular mode. This work presents the sensing and control methodology required for transition between charging and propulsion modes of operation. The mode transition is achieved using optimal number of sensing elements. The state transition control is implemented using a state machine based approach and the mode transition behavior has been validated in PLECS- based simulation of a reconfigurable converter meant for 1.2 kW BLDC-based motoring and 0.9 kW charging operation. The proposed state transition control has also been validated in OPAL-RT real time simulator with external FPGA controller for replicating practical conditions.

Reconfigurable battery systems enable dynamic switching between series and parallel configurations, optimizing power distribution and enhancing battery performance. However, maintaining battery voltage balancing and DC bus regulation remains a critical challenge, especially in systems with varying load demands. This article presents an Integrated Dual-Input Converter (IDIC) designed to achieve effective battery voltage balancing and stable DC bus regulation in modular reconfigurable battery packs. The modular architecture of the converter enhances flexibility by dynamically adjusting the power flow between battery modules, preventing the overloading of individual cells and ensuring a uniform voltage distribution. Modular systems provide the flexibility to accommodate different voltage levels, adapt to changing load conditions, and improve battery utilization. Instead of using multiple semiconductor switches directly connected to the battery terminals, the proposed converter utilizes relay switches to toggle between battery modules. This approach significantly reduces switching losses, conduction losses, and costs while simplifying the control strategy. Simulation and experimental results validate the effectiveness of the proposed approach in maintaining balanced battery voltages and stable DC bus operation, making it a suitable solution for various battery-powered applications.

The dual active bridge (DAB) converter is a bidirectional dc-dc converter having wide range of applications such as in renewable energy systems, electric vehicles (EV), dc microgrids, etc. This paper presents a SiC MOSFET-based phase shifted and quasi-square-wave modulated (PSQSWM) DAB converter for on-board charging application. There is more flexibility in controlling the active power flow in the converter by introducing a phase shift between the carriers of the two bridges as well as changing the width of the switch gate-pulses in one of two bridges. The different modes of operation have been discussed and MATLAB-Simulink digital simulation platform has been used verifying the control of the DAB converter.

PV-interfaced dc-dc converters have found extensive use in widespread consumer electronic applications, including rooftop solar homes, solar pumps, PV-fed battery energy storage systems (PV-BESS), and solar lanterns. In these systems, the output voltage of the power processor depends on the specific application, while the input voltage may vary widely in multipanel configurations due to changing environmental conditions. Hence, a reconfigurable power processor with wide voltage adaptability is essential to effectively harness the maximum available power from the PV source. Conventional maximum power point tracking (MPPT) techniques rely on solar current measurement, requiring additional sensors, biasing, and signal conditioning circuits connected in series with the current path, thereby increasing system cost and complexity. This work presents a current-sensorless embedded maximum power tracker for a PVinterfaced reconfigurable power processor. The proposed method utilizes shunt-type voltage measurements to estimate the solar panel output current, eliminating the need for physical current sensors while maintaining MPPT performance. The proposed approach is validated using PLECS simulation software and experimentally using a laboratory prototype connected to a PV emulator operating in voltage boost mode, under both unbounded (standalone load) and bounded (battery-assisted) operating conditions, demonstrating its effectiveness and suitability for wide voltage range applications.

Solar energy harvesting circuits play a major role in powering portable consumer electronic applications. Batteries are also associated as a power source in these applications as a power balancing element. This work evaluates the performance of an battery-assisted integrated three-port converter used for solar energy harvesting. The novelty of the converter lies in the flexibility to operate in different operating modes using the same architecture through its pulse width modulation control at the same voltage level. The adaptive nature of converter operation enables peak power extraction with reduced solar power oscillations under rapid and slow varying insolation conditions at different weather conditions. The theory of operation has been validated using a 250 W experimental prototype of the three port converter for different operating conditions and closed loop controller has been verified with rapid dynamic changes in operating conditions.

Current mode control (CMC) techniques for switched mode converters are extensively used as they provide faster dynamic response and tight output voltage regulation. The current mode control technique requires the inductor's current as feedback to the system. However, real-time high-frequency inductor current sensing requires high bandwidth current sensors and high sampling rate analog to digital converters (ADCs). Furthermore, incorporating a current sensor (i.e., sensed resistor, hall sensor) leads to breakage of the path of the circuit and requires additional signal conditioning circuits. To address these challenges, this work evaluates a non-invasive embedded current measurement technique that uses terminal voltage measurement of the converter and an analog comparator connected to the switch node of the converter to reconstruct the inductor current within the digital controller. Nevertheless, this technique necessitates average terminal voltage sensing, hence the voltage can be sampled with low sampling frequency ADCs. Furthermore, the proposed current estimation concept is also applicable to multiport converters with multiple inductors in the circuit. Hence, this technique reduces the requirement for multiple current sensors and high-end ADCs. The proposed theory has been implemented using an FPGA-based digital platform used for controlling the switched mode converters. Moreover, the current estimation technique is validated using a laboratory-scale prototype of a boost converter and integrated dual dc boost multiport converter (IDDBC).

Non-inverting buck-boost converters are widely used in applications requiring voltage regulation with a constant output polarity. These include fuel cell systems, battery-powered devices, telecommunication equipment, and electric vehicle charging infrastructure. This paper presents a detailed analysis of a four-switch, non-isolated, non-inverting buck-boost converter, focusing on the impact of non-idealities such as switch resistances. The study derives expressions for voltage gain and inductor current ripple under different operating modes-buck, boost, and buck-boost-considering the influence of parasitic elements. The control of the converter is achieved through independent modulation of the switching duty cycles, enabling flexible operation across a wide voltage range. The proposed theory is verified in simulation using the MATLAB-Simulink platform.

Precise identification of fault location in dc microgrids is essential for prompt maintenance and quick power restoration. This article proposes a portable power electronic fault localization unit (PEFLU) that can identify the fault location within a low-voltage dc (LVdc) microgrid by estimating the inductance of the distribution line. The proposed scheme is based upon a current sensorless approach, and hence, compared to existing methods, it eliminates the need for current sensors and high-frequency sampling stages for fault localization. The proposed unit operates post-deenergization of faulty line using internal measurements (i.e., terminal voltage measurements of PEFLU) to locate the fault, without involving any measurements from other points of the distribution line. The sensors for PEFLU act upon low-bandwidth average voltage measurements rather than instantaneous voltages in order to estimate fault location. This article discusses the theory behind estimation of fault location, which is verified using simulation analysis on a low-voltage dc microgrid system. The proposed concept has also been validated using a laboratory-scale testbed using converter prototype of PEFLU acting on a distribution system.

Lightweight electric vehicles (LEVs) make up a significant chunk of the EV market in India. In the LEV segment, brushless de (BLDC) motors are prevalent. However, the current Indian market is dominated by the open loop controllers that drive the motors, which lack proper standards and have adverse effects on the battery packs. In these types of controllers, impulse discharge of batteries is very common, making battery maintenance a challenging task to perform. This paper proposes a Fuzzy logic-based adaptive controller for the BLDC motors used in the LEVs. A fuzzy logic-based speed loop is introduced in the system to improve the battery life of the LEVs by reducing the effect of the impulse discharge of the batteries. Furthermore, the proposed approach is a current sensorless method, hence, the incremental cost to implement this system is also negligible. The step-by-step implementation of the fuzzy logic controller using an FPGA is elaborately discussed in this paper. The proposed controller is verified using a laboratory-scale prototype using a 48 V, 1 kW bldc drivetrain for different operating conditions.

Precise operation and control of electric drives in industrial applications, e.g., e-mobility, involve power electronic converters using feedback regulators connected to system state sensors. Typically, the torque of electric motors is directly related to current, and hence this necessitates accurate current sensing. An embedded controller used for a high-frequency drive application requires high bandwidth current sensors followed by high-resolution analog-to-digital converters (ADCs) for feedback regulation, which reflects on the cost and component count of the overall system. Current sensor-less estimation approaches provide an alternate possibility to mitigate the above drawbacks. This letter investigates a voltage-based current estimation approach for speed control of dc motor systems. The estimation of current utilizes only varying shunt (voltage) measurements, which can have dynamic variation, to estimate motor current without using high bandwidth current sensors and high-speed ADCs. Incorporating this estimation approach successfully achieves precise speed control of dc motor systems, demonstrating a cost-effective and component-efficient alternative to traditional high-bandwidth current sensing methods. The estimate of the current obtained can be incorporated with a digital control system for motor control. The theory and implementation of the proposed technique have been presented in the paper using a laboratory test-bed of a dc-motor with an FPGA-based controller.

Multiport power electronics converters enable interfacing of multiple sources and loads within a renewable-rich dc microgrid. The system evaluation of these microgrids such as dynamic performance of components, stability analysis are often evaluated using hardware-in-loop (HIL) approach for different real time conditions. The digital twin of device under test (DUT) is realized within real time simulator using voltage and current sensor measurements in the HIL-based testing approach. Current sensing systems for multiport power converter systems require transducers to be connected in path of current with restrictions on sensor bandwidth, auxiliary circuit overhead requirements for biasing and signal conditioning. This paper addresses the development of high frequency current sensing method using shunt-type measurements with reduced auxiliary circuit overheads. The proposed method provides a digital estimate of inductor current which can be implemented in an embedded processor.

The estimate of inductor dc resistance (DCR) is required for different aspects of dc-dc converter operation such as power sharing among parallel converters, current-sensorless sensing, and controller tuning. The dc resistance of the inductor within a dc-dc converter also includes trace resistance of the circuit path and switch on-state resistance ( $r_{dson}$ ). The latter parameters are intrinsic characteristics of the power converter layout, and hence, a different approach has to be considered to evaluate these parameter's values after fabrication. Due to application-specific constraints (e.g., measuring point accessibility, and variation in operating conditions), the value of non-ideal parameters needs to be estimated indirectly in situ rather than directly measured using a meter. This work presents a generalized method for estimating DCR in dc-dc converters using a series combination of a measuring resistor and a switch (R-Sw). This R-Sw arrangement can be either part of the converter or within a separate meter. Furthermore, it can be used with the existing closed-loop control system to determine not only the inductor DCR but also the switch $r_{dson}$ and the diode voltage drop, current sharing between parallel connected converter, and multiport converter. The theory of operation, design, and digital implementation aspects of the proposed approach has been presented with respect to single-order dc-dc converter topologies. Experimental results validate the proposed concept of operation.

Multi-port dc-dc converters find significance in applications such as renewable integration, and hybrid- source systems. Power flow control and its management is one of the major challenges associated with multi-port converters. This work proposes a hybrid model predictive controller for control of power within the integrated dual dc boost converter topology. This topology is a three-port converter with one bidirectional port (suitable for an energy buffer, eg. battery). Due to sharing of control duty ratio using the same set of controllable switches, using separate controllers for each control objective results in cross-regulation within the different ports. This work presents the model predictive controller which can simplify control design for the multi-port system and hence provide robustness to the regulated system. The design of the controller and its evaluation is presented in this work.

The bipolar dc microgrid configuration ensures enhanced efficiency, flexibility, and improved power quality compared to unipolar dc-based distribution. However, a bipolar structure is susceptible to voltage imbalance caused by asymmetric loading between its two poles. In such cases, power electronic converters with constant power characteristics can provide additional overload to these bipolar lines. This article presents a novel three-port dc-dc power electronic interface whose impedance can be dynamically adjusted to regulate both the pole voltage magnitudes (under balanced or unbalanced conditions) with reduced overloading while feeding a constant power load. The performance of the proposed configuration has been assessed using a three-port structure referred to as the integrated dual input converter (IDIC). The analysis of the converter operating modes, its pulsewidth modulation control, and the closed-loop system design for the bipolar dc distribution interface has been developed in this article. The theory of operation and control behavior has been validated using experimental testing on a laboratory scale prototype of IDIC.