Phase-shifted Carrier Research Articles

Design and Implementation of Two-phase Boost Inverter using Interleaved Method to Increase Output Current

The advancement of technology is rapidly evolving, particularly in the field of electronics, namely power electronics. One of the applications is the use of new and renewable energy. The converters required in new and renewable energy are inverters with good quality and performance. The step-down (buck) inverter is commonly used in this application. Different from the normal inverter, the step up (boost) inverter is proposed to be analyzed, simulated, and implemented in this paper. The proposed inverter uses a two-phase interleaved boost inverter (TP DC-AC IBI) consisting of a full bridge inverter and dual AC-AC interleaved boost converter. The inverter part always converts DC voltage to AC voltage, while the dual AC-AC interleaved boost converter part serves to increase the output voltage. The inverter consists of three arms: the first and second arms are controlled by Sinusoidal Pulse Width Modulation (SPWM) using 180° phase-shifted carrier signal, and the third arm is controlled by a zero-crossing detector. Pulse Width Modulation (PWM) is used to control dual AC-AC interleaved boost converter. By combining this inverter with dual AC-AC interleaved boost converter, a new topology is created. This study specifically investigated the strategy to control this new topology using current controls. The actual current was obtained by installing an HX-10P current sensor on the output side. The output current was compared with the reference current, and the next stage was controlled using a proportional plus integral controller. The control signals output was modulated using SPWM signals on the inverter side and PWM at the AC-AC interleaved boost converter side to drive many power switches. To guarantee that the desired current control can always be achieved, the actual current and reference current must always match. The proportional plus integral controller was chosen due to its simplicity, high accuracy, and quick response time. The analysis involved verifying simulation tests using Power Simulator (PSIM) software. The hardware implementation was conducted in the laboratory and tested using standardized equipment. A couple of inductors were installed to reduce harmonic current on the output side and obtained THD of 3.3%, which according to the IEEE 519-2014, has met the standard as it was less than 5%. Thus, this new topology can be used in new and renewable energy for its good performance.

Novel multi-modular power conditioning system and decoupling control strategy for SMES with coupled superconducting coil

The high-temperature superconducting magnetic energy storage system (HTS-SMES) utilizes a superconducting coil (SC) to store electric energy in a magnetic field. It has several advantages such as high efficiency, fast response, and infinite charge–discharge cycles. Coupling two SCs made of different HTS materials, known as coupled SC (CSC), can enhance the utilization rate of HTS tapes, reduce manufacturing costs, increase the energy storage density of the SC, and lower magnetic leakage. However, the presence of a coupled magnetic field in CSC makes precise power and current regulation of the individual SC challenging. Additionally, the self-inductances of the individual SCs, composed of different materials, typically differ from each other. Consequently, the current variation induces electromotive force in each SC that differs from the others, necessitating the design of power converters with different voltage ratings connected to each SC. To address the difficulties associated with SMES implementation using CSC, this paper proposes novel modular power conditioning system (MPCS) and decoupling control strategy for SMES. The MPCS enables the flexible design of individual SC power ratings by selecting the appropriate number of power modules. The decoupling control ensures precise current control of each individual SC, which significantly reduces the current ripple of the SCs. Moreover, by employing carrier phase shift modulation, the total harmonic distortion (THD) of the PCS output current is as low as 0.79%. Furthermore, the feedforward power control is proposed to reduce the power control overshoot, and the current sharing control is presented to ensure precise current sharing between each SC. Simulation results verify the efficacy of the proposed approaches.

Doppler Compensation Techniques for M-Ary Sequence Spread Spectrum Signals Based on Correlation Cost Factors in Mobile Underwater Acoustic Communication

Unlike terrestrial radio, the speed of sound in the ocean is relatively slow, which results in mobile underwater M-ary spread spectrum communication typically exhibiting significant and variable multipath effects along with strong Doppler effects, leading to rapid carrier phase shifts in the received signal that severely impact decoding accuracy. This study aims to address the issue of rapid carrier phase shifts caused by significant time-varying Doppler shifts during mobile underwater M-SS communication. This paper innovatively proposes a method for updating matched filters based on correlation cost factors. By calculating the correlation cost factors for each received symbol, the method guides the direction of Doppler estimation and updates the matched filters. After identifying the optimal match, the received symbols are shifted, correlated, and decoded. Simulation and sea trial results indicate that this method demonstrates higher computational efficiency and improved decoding accuracy compared to traditional Doppler estimation matched filters under low signal-to-noise ratio conditions, and exhibits greater robustness under complex motion conditions.

Parallel two-step spatial carrier polarized phase-shifting common-path digital holography

A zero-order term causes bad effect on the phase reconstruction of off-axis holography, which can be solved by two-step carrier phase-shifting. Therefore, a common-path digital holography is proposed by using parallel two-step spatial carrier polarized phase-shifting in a 4f optical system for quantitative phase imaging. This holography is established based on a 4f optical system by inserting a 45° tilted cube polarized beamsplitter to split the horizontal and vertical polarization components in one beam. Via intentional polarization modulation, two off-axis holograms with π/2 phase-shift can be captured in one shot, so the subtraction between two holograms would cancel out the zero-order term. The phase distribution of a thin specimen can be retrieved with enhanced quality. There are two apertures at the input plane of the 4f optical system, one for object and the other for nothing, while only one polarized cube beamsplitter is inserted into a 4f optical system. Thus, this system is common-path with strong anti-noise ability and high stability, while it also has simple optical configuration and easy optical alignment. Several experimental results would be presented to demonstrate the validity of the proposed holography.

Topology, Analysis, and Modulation Strategy of a Fully Controlled Modular Reconfigurable DC Battery Pack With Interconnected Output Ports for Electric Vehicles

Modular battery-integrated converters or so-called dynamically reconfigurable battery packs are expanding into emerging applications. Although they offer many degrees of freedom (DoF), the state of the art focuses on single-output systems and neglects the potential of such systems to generate multiple outputs with minimum added components. This paper investigates the feasibility of a multiport system for various independent loads. The proposed techniques can achieve higher functionality and reduce power conversion stages. Interleaved ports with shared modules can also increase modules’ utilization, avoid redundant power electronics, and reach a better cost-weight trade-off. However, using conventional modulation techniques in particular phase-shifted carrier modulation can be challenging with shared modules among multiple ports, and different control objectives can adversely impact the overall performance. Therefore, this paper analyzes the inherent dynamics of modular batteries and proposes a strategy to decouple the control of multiple ports to simplify power electronics’ complexity and size while improving performance. In addition to the distinct advantages of modular reconfigurable batteries, the proposed concept would not require additional active switches, can operate with a wide range of output voltages, can reduce the size of the filters and transformers, and is extendable to larger setups. Simulation and experiments verify the developed concept.

High-Frequency Current Harmonic Analysis and Suppression in Dual Three-Phase PMSMs With Advanced Carrier Phase-Shift PWM

High-Frequency Current Harmonic Analysis and Suppression in Dual Three-Phase PMSMs With Advanced Carrier Phase-Shift PWM

Improved carrier phase shift modulation and voltage equalization control strategy in modular multilevel converter

Improved carrier phase shift modulation and voltage equalization control strategy in modular multilevel converter

Harmonic Optimization Strategy of Aviation Multi-unit PMSM Generation System Based on Improved Carrier Phase Shift Modulation Method

Harmonic Optimization Strategy of Aviation Multi-unit PMSM Generation System Based on Improved Carrier Phase Shift Modulation Method

Circuit simulation-based comparison of power electronics devices in a five-level converter for UAV applications

<p>In this paper, the performance of a 5-level cascaded H-bridge inverter in unmanned aerial vehicle (UAV) applications is analized to identify, at the converter design stage, the better device choice depending on different UAV operation scenarios. Considering that regardless of the specific application there are some typical operations, such as take-off, climb, land, cruise, and potential recurring climbs and descents, the results can support the choice by considering the typical working conditions of the specific application where the UAV would be used. The results have been obtained by simulating the H-bridge inverter considering the circuit models of insulated-gate bipolar transistors (IGBTs), GaN high-electron-mobility transistors (HEMTs), and Si and SiC metal-oxide-semiconductor field-effect transistors (MOSFETs) provided by manufacturers. The study has highlighted that the choice of the device depends on the UAV usage, switching frequency, and load conditions. More specifically, considering the typical devices and systems costs in the case of a selective harmonic elimination procedure operating at the fundamental switching frequency, the Si devices should be used. Moreover, the preference for using IGBTs or Si MOSFETs depends on the typical working conditions of the UAV application. In the case of phase-shift carrier modulation technique, at 4 kHz the MOSFET is the best device and the choice between Si and SiC devices depends on the UAV application's main operation scenarios. At 20 kHz the SiC MOSFET is the best device, while at higher frequencies the GaN HEMT cost should be faced to take advantage of its best performance.</p>

Velocity Estimation Using Time-Differenced Carrier Phase and Doppler Shift with Different Grades of Devices: From Smartphones to Professional Receivers

Velocity estimation has a key role in several applications; for instance, velocity estimation in navigation or in mobile mapping systems and GNSSs is currently a common way to achieve reliable and accurate velocity. Two approaches are mainly used to obtain velocity based on GNSS measurements, i.e., Doppler observations and carrier phases differenced in time (that is, TDCP). In a benign environment, Doppler-based velocity can be estimated accurately to within a few cm/s, while TDCP-based velocity can be estimated accurately to within a few mm/s. On the other hand, the TDCP technique is more prone to availability shortage and the presence of blunders. In this work, the two mentioned approaches are tested, using three devices of different grades: a high-grade geodetic receiver, a high-sensitivity receiver, and a GNSS chip mounted on a smartphone. The measurements of geodetic receivers are inherently cleaner, providing an accurate solution, while the remaining two receivers provide worse results. The case of smartphone GNSS chips can be particularly critical owing to the equipped antenna, which makes the measurements noisy and largely affected by blunders. The GNSSs are considered separately in order to assess the performance of the single systems. The analysis carried out in this research confirms the previous considerations about receiver grades and processing techniques. Additionally, the obtained results highlight the necessity of adopting a diagnostic approach to the measurements, such as RAIM-FDE, especially for low-grade receivers.

Variable Carrier Phase-Shift Method for Integrated Contactless Field Excitation System of Electrically Excited Synchronous Motors

Variable Carrier Phase-Shift Method for Integrated Contactless Field Excitation System of Electrically Excited Synchronous Motors

Carrier Phase Shift Method of SPWM for Concurrent Wired and Wireless Power Transfer Systems

This paper presents an approach for concurrent power transfer to wired and wireless systems using just a single inverter. The approach utilizes a novel carrier phase-shift (CPS) method that independently controls the inverter output voltages at the fundamental and switching frequencies. This proposed method can be a cost-effective solution to wireless power transfer (WPT) systems used in contactless slip rings (CSR), which transfer power to auxiliary loads such as sensors, radars, and IoT devices. There are two separate converters in conventional CSR systems: one is for the motor drive, and the other is for the WPT system. It is proposed that the switching harmonics of the motor drive can also be utilized to excite the WPT system while the low-frequency component can still be used to drive the motor. In order to control these independently, the CPS method is introduced. The proposed method is investigated analytically for sinusoidal-PWM (SPWM). Then, an experimental setup consisting of a 3-phase 3-wire GaN-based inverter and a 3-phase motor is built. Experimental results show that the WPT and motor systems are operated concurrently, and their powers are controlled independently by the proposed method.

A Novel Carrier Based Precharging Technique for Single-Phase Odd-Level Flying Capacitor Multilevel Converters (FCMCs)

Flying Capacitor Multilevel Converter(FCMC) needs all its flying-capacitors charged to the appropriate voltage levels during stat-up. This paper presents a novel carrier based precharging technique for single-phase odd-level FCMCs. A new set of modified phase-shifted carrier signals are derived for precharging. These carrier signals when compared to zero modulation signal, ensure the synthesisation of sufficient number of zero output voltage switching modes (zero-modes) of the converter. The proposed precharging technique is detailed using a five-level FCMC and then generalized to higher odd-level FCMCs. State-space averaging models are derived to validate the proposed technique mathematically. Extensive simulation and experimental results are provided to validate the functionality of the proposed technique.

Fault detection and localization method for modular multilevel converters in offshore DC wind turbines

The offshore DC wind turbine, consisting of direct-drive permanent magnet synchronous generator (PMSG) and modular multilevel converter (MMC), has become a promising candidate for the large-capacity wind energy conversion system. Submodule (SM) failure detection and localization are crucial for reliable operation of the MMC. However, existing techniques mainly focus on the rated operation condition, which may not be suitable for the MMC in wind turbine due to varying wind speed. Moreover, proper injection of second-order harmonic circulating current (SHCC) is desirable to reduce capacitor voltage ripple and power loss, which may also affect the accuracy of fault detection. This paper proposes a fault-tolerant strategy immune to variable operation conditions, as well as SHCC injection, for the MMC with phase-shifted carrier modulation. Firstly, the inherent switching harmonics of circulating current with SM failure are analyzed, based on which the fault detection method is developed. Then, the localization approach is presented by measuring the difference of SM capacitor voltages. Compared with existing techniques, the proposed strategy requires neither estimator nor additional sensor, which is robust, simple, and economical. Finally, both simulation and experimental results demonstrate the effectiveness of the proposed method, which is not influenced by SHCC and varying wind speed.

A New Model-Based Dead-Time Compensation Strategy for Cascaded H-Bridge Converters

Cascaded H-bridge multilevel converter can generate high-voltage and high-power output with low harmonics. However, the error voltage caused by dead time effect will distort the output waveform, which depends on the phase current polarity. Since the normal dead time compensation method based on current sampling is often disturbed by sampling error and transmission delay, a novel current prediction method is proposed for dead time compensation of cascaded H-bridge converter in this paper. This method, based on phase shift carrier pulse width modulation, reconstructs the switch pattern, and combined with the system model, can easily predict the phase currents. Excellent compensation performance can be obtained by dead time compensation according to the predicted current. Simulation and experiments are built to validate the excellent performance of the proposed method applied to cascaded H-bridge converters.

Discrete-Time Sliding Mode Current Control for a Seven-Level Cascade H-Bridge Converter

This paper deals with the implementation and performance analysis of discrete-time sliding mode (DTSM) current control applied to a seven-level cascade H-bridge converter to track three-phase reference currents for a reactive load. The converter output voltages are synthesized using a modulation scheme based on phase-shifted carrier modulation. Simulation and experimental tests have been added to demonstrate the performance of the proposed controller. At the same time, the effectiveness of the DTSM is verified under transient and steady-state conditions, respectively, by measuring the total harmonic distortion and the mean square error.

A Method Based on Phase-shifting Carrier for Reducing DC-link Current Harmonics in Dual Three-phase PMSM Drive under Open-phase Conditions

The All-Electric of modern military equipment has become an important trend, in the field of aircraft the traditional servo control focus on the exact control of the motor. With the development of power electronics technology, a high-power motor has expanded into a multiphase kind which cast off the limitation of traditional three-phase motors. The multiphase motor has more control resources and fault-tolerant control ability under the fault condition, which has practical meaning for high safety and high-reliability applications in an airborne environment. The multiphase motor can be controlled by a series of phase-shift carriers, which can reduce DC current ripple more effectively than the traditional carrier-based pulse width modulation, but it needs to find the optimal phase shift angle. In this paper, the optimal carrier phase shift angle is analyzed mathematically which can be used for both under health and single open-phase fault of a dual three-phase motor, and the simulation result illustrates that the carrier phase shift method used in this paper has the DC current ripple optimization effect.

Common DC-Link Capacitor Harmonic Current Minimization for Cascaded Converters by Optimized Phase-Shift Modulation

This paper investigates the influence of a constant carrier phase shift on the DC-link capacitor harmonic current of cascaded converters used in fuel-cell and mild-hybrid electric vehicles. In these applications, a DC-DC converter can be adopted between the battery and the motor drive inverter in a cascaded structure, where the two converters share the same DC-link. Since the DC-link capacitor of such a system represents a critical component, the optimization of the converter operation to limit the current stress and extend the lifetime of the capacitor is an primary objective. This paper proposes the use of a carrier phase shift between the modulations of the two converters in order to minimize the harmonic current of the DC-link capacitor. By harmonic analysis, an optimal carrier phase shift can be derived depending on the converter configuration. Analytical results are presented and validated by hardware-in-the-loop experiments. The findings show that the pulse width modulation carrier phase shift between the interleaved boost converter and the voltage source motor drive inverter has a significant influence on the DC-link capacitor current and thus on its lifetime. A case study with two-cell and three-cell interleaved boost converters shows a possible DC-link capacitor lifetime extension of up to 390%.

Simplified loss calculation model for medium voltage modular multilevel converter

Modular multilevel converter (MMC) has broad application prospects in medium voltage scenarios such as DC distribution networks. Medium and low voltage MMC usually use carrier phase shift PWM (CPS-PWM), and the analytical formula of zero crossing point of MMC arm current considering double frequency circulating current component is complex, resulting in the existing MMC loss accurate calculation models are very complex and slow. To solve this problem, this paper proposes a simplified loss calculation model for MMC considering the equivalent of switching devices, which can easily, quickly and accurately calculate converter power losses under different operating conditions without and with circulation suppression, especially reveal the mathematical relationship between converter power losses and its double frequency circulation current component. Finally, based on actual engineering parameters, a comparative analysis of multiple operating conditions is carried out in the MATLAB/Simulink simulation, which verifies the correctness and accuracy of the proposed simplified loss calculation model.

A Robust Capacitor Voltage Balancing Method for CPS-PWM-Based Modular Multilevel Converters Accommodating Wide Power Range

Capacitor voltage balancing is one of the most important issues for the safe, reliable, and economical operation of the modular multilevel converter (MMC). This article proposes a modified individual capacitor voltage balancing method for MMCs with phase-shifted carrier pulsewidth modulation (PWM) (CPS-PWM) to solve the problem of the poor dynamic performance that the conventional individual voltage balancing methods suffer at low output power. In the proposed method, the information of arm current is incorporated into the balancing algorithm to cancel out the coupling effect of the output power on balancing control. Compared with conventional balancing methods, the proposed method shows better robustness against varying output power and maintains a good dynamic performance in a wider power range. The complete modeling process and parameter design are presented and considered for system stability. The effectiveness of the proposed method is verified with both MATLAB/Simulink simulation and experimental results.