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This paper aims to present a cascaded pseudo derivative feedback (PDF) plus pseudo derivative feedback plus pseudo derivative feedforward (PDFF) controller for a permanent magnet synchronous motor (PMSM) to improve the transient response of the system.

Proportional integral (PI) plus PI controller and the proposed PDF plus PDFF controller are designed, stability analysis is performed using the extended root locus method, and the effect of the damping coefficient is also extensively studied to validate the robustness of the proposed controller.

When compared to a cascaded PI plus PI controller, the proposed control approach has a much shorter settling time for the entire system and a 50% reduction in overshoot in stator current under extensive variations in speed with load disturbance.

The proposed controller is programmed into an FPGA Altera Cyclone II and applied to a 1.5 kW laboratory prototype PMSM drive. The effectiveness of the proposed methods has been demonstrated experimentally throughout a wide variable speed range, from 0 to 157 rad/s at different load conditions.

This paper aims to propose and verify an improved cascade active disturbance rejection control (ADRC) scheme based on output redefinition for hypersonic vehicles (HSVs) with nonminimum phase characteristic and model uncertainties.

To handle the nonminimum phase characteristic, a tuning factor stabilizing internal dynamics is introduced to redefine the system output states; its effective range is determined by analyzing Byrnes–Isidori normalized form of the redefined system. The extended state observers (ESOs) are used to estimate the uncertainties, which include matched and mismatched items in the system. The controller compensates observations in real time and appends integral terms to improve robustness against the estimation errors of ESOs.

Theoretical and simulation results show that the stability of internal dynamics is guaranteed by the tuning factor and the tracking errors of external commands are globally asymptotically stable.

The control scheme in this paper is expected to generate a reliable way for dealing with nonminimum phase characteristic and model uncertainties of HSVs.

In the framework of ADRC, a concise form of redefined outputs is proposed, in which the tuning factor performs a decisive role in stabilizing the internal dynamics of HSVs. By introducing an integral term into the cascade ADRC scheme, the compensation accuracy of matched and mismatched disturbances is improved.

The purpose of this paper is to propose a DC-port voltage balance strategy realizing it by logic combination modulation (LCM). This voltage balance strategy is brief and high efficient, which can be used in many power electronic devices adopting the cascaded H-bridge rectifier (CHBR) such as power electronic transformer (PET).

The CHBR is typically as a core component in the power electronic devices to implement the voltage or current conversion. The modulation method presented here is aiming to solve the voltage imbalance problem occurred in the CHBR with more stable work station and higher reliability in ordinary operating conditions. In particular, by changing the switch states smoothly and quickly, the DC-port voltage can be controlled as the ideal value even one of the modules in CHBR is facing the load-removed problem.

By using the voltage balance strategy of LCM, the problem of voltage imbalance occurring in three-phase cascaded rectifiers has been solved properly. With the lower modulation depth, the efficiency of the strategy is shown to be better and stronger. The strategy can work reliably and quickly no matter facing the problem as load-removed change or the ordinary operating conditions.

The limitation of the proposed DC-port voltage balance strategy is calculated and proved, in a three-module CHBR, the LCM could balance the DC-port voltage while one module facing the load-removed situation under 0.83 modulation depth.

This paper provides a useful and particular voltage balance strategy which can be used in the topology of three-phase cascaded rectifier. The value of the strategy is that a brief and reliable voltage balance method in the power electronic devices can be achieved. What is more, facing the problem, such as load-removed, in outport, the strategy can response quickly with no switch jump and switch frequency rising.

The purpose of this paper is to design a cascaded Multilevel inverter with reduce number of switches for high power applications. This paper came up with an innovative three-phase multilevel inverter (MLI) topology, which is a cascaded structure based on classical three-legged voltage source inverter (VSI) bridges as an individual module. The prominent advantage of this topology is that it requires only one direct current (DC) link system. The main characteristic of it is that a higher number of voltage levels can be achieved with considerably a smaller number of semiconductor switches, which improves the reliability, power quality, cost and size of the system significantly.

The individual modules are cascaded through three-phase transformers to provide higher voltage at the output with the higher number of voltage levels. In this work, the phase-shifted pulse width modulation technique is implemented to verify the result.

The proposed topology is compared with three-phase cascaded H-bridge MLI (CHB-MLI) and a modified CHB-MLI topology and found better in many aspects. The proposed MLI can produce a higher number of voltage levels with fewer semiconductor switches and associated triggering circuitry. As the device count in the proposed MLI is less compared to other MLI discussed, it tends to have less switching and conduction loss which increases the efficiency and reliability. As the number of level increases, the voltage profile and the total harmonic distortion of the proposed MLI improves.

This is a transformer-based modular cascaded MLI, which is based on classical VSI bridges. Here in this topology, a single module provides all three phases. So, a single string of cascaded modules is enough for three-phase multilevel voltage generation.

Small highly saturated interior permanent magnet- synchronous machines (IPMSMs) show a very nonlinear behaviour. Such machines are mostly controlled with a closed-loop cascade control, which is based on a d-q two-axis dynamic model with constant concentrated parameters to calculate the control parameters. This paper aims to present the identification of a complete current- and rotor position-dependent d-q dynamic model, which is derived by using a finite element method (FEM) simulation. The machine’s constant parameters are determined for an operation on the maximum torque per ampere (MTPA) curve. The obtained MTPA control performance was evaluated on the complete FEM-based nonlinear d-q model.

A FEM model was used to determine the nonlinear properties of the complete d-q dynamic model of the IPMSM. Furthermore, a fitting procedure based on the nonlinear MTPA curve is proposed to determine adequate constant parameters for MTPA operation of the IPMSM.

The current-dependent d-q dynamic model of the machine models the relevant dynamic behaviour of the complete current- and rotor position-dependent FEM-based d-q dynamic model. The most adequate control response was achieved while using the constant parameters fitted to the nonlinear MTPA curve by using the proposed method.

The effect on the motor’s steady-state and dynamic behaviour of differently complex d-q dynamic models was evaluated. A workflow to obtain constant set of parameters for the decoupled operation in the MTPA region was developed and their effect on the control response was analysed.

COVID-19 has forced Big 4 firms to challenge existing management control arrangements and adapt their ways of working. Yet, we know little about how management control might be enacted in the future of the sustainable workplace. The objective of the study is to examine the patterns of management control change in the Big 4 accounting firms during the COVID-19 pandemic.

Adopting an exploratory qualitative research design, the authors draw on 42 interviews with directors and associates in the Big 4 professional services firms.

The findings reveal two pathways of management control change including alignment and displacement. The authors found that relatively minor adaptions to action and result controls were relied upon to respond to substantial cultural and personnel control changes.

The contributions are threefold: the authors take a temporal perspective to (1) unpack the changes to management control arrangements; (2) theorise the findings by developing a three-dimensional taxonomy of change pathways encompassing pace, scope and longevity of management control change and (3) contextualise management control arrangements in a hybrid work setting.

1. COVID-19 has forced Big 4 firms to challenge existing management control arrangements.

2. Literature has focused on traditional, onsite work settings and largely ignored change pathways.

3. The authors take a temporal perspective to unpack changes to management control arrangements.

4. Big 4 firms adapted to hybrid work with substantial changes to personnel and cultural controls.

5. The authors theorise the findings by developing a three-dimensional taxonomy of change pathways.

COVID-19 has forced Big 4 firms to challenge existing management control arrangements.

Literature has focused on traditional, onsite work settings and largely ignored change pathways.

The authors take a temporal perspective to unpack changes to management control arrangements.

Big 4 firms adapted to hybrid work with substantial changes to personnel and cultural controls.

The authors theorise the findings by developing a three-dimensional taxonomy of change pathways.

This study aims to investigate the dynamic interplay between the management control system (MCS) and organizational identity (OI) in the Deepwater Horizon incident involving British Petroleum (BP). It examines how the MCS manages challenges, particularly those addressing the embarrassment stemming from identity disparities between external portrayal (frontstage) and internal operations (backstage), with a focus on the often-underestimated influence of the media.

This study builds upon the frameworks developed by Ravasi and Schultz (2006) and Malmi and Brown (2008) to construct a theoretical framework that profoundly investigates the relationship between MCS and OI. The framework developed guided the research design and incorporated a qualitative approach complemented by an illustrative case study. The research data was rigorously gathered from diverse sources, including official BP documents and influential media outlets, with a particular focus on well-established American and British newspapers.

BP’s MCS plays a dual role: it exposes discrepancies in safety, leadership and values, causing embarrassment and identity damage, yet catalyses a sense-making process leading to organizational transformation and shifts in the OI. This transformation influences sense-giving and prompts changes in MCS. The study reveals an intricate interplay in identity management between frontstage audiences (e.g. influential media) and backstage actors (e.g. BP’s senior management). It highlights interdependencies both within and between MCS and OI, emphasizing their roles in interacting within identity management. The longitudinal recovery is intricately tied to mutual political interests between BP and the USA, which are significantly facilitated by the media’s role.

This study acknowledges limitations that point future research opportunities. Interviews could provide a more dynamic understanding of MCS changes and organizational transformations. Investigating the role of leadership, particularly the new chief executive office, and the influence of political versus organizational factors in shaping identity claims is essential. Additionally, the effectiveness and historical context of interdependencies should be quantitatively assessed. Theoretical limitations in the OI and MCS frameworks suggest the need for context-specific categorisations. This research serves as a foundation for further exploration of the intricate dynamics between MCS, OI and organizational responses to crises.

This study offers valuable insights with practical implications for organizations facing identity challenges in the wake of significant incidents. Organizations can better navigate crises by recognizing the multifaceted role of MCS in identity damage and restoration. It underscores the importance of addressing both frontstage and backstage aspects of OI while managing identity discrepancies, thereby enhancing transparency and credibility. Additionally, understanding the intricate interdependencies within OI and MCS can guide organizations in implementing more effective identity restoration strategies. Furthermore, the study highlights the significance of media influence and the need to engage with it strategically during crisis management.

This study’s findings have significant social implications for organizations and the broader public. By recognizing the multifaceted role of MCS in shaping identity, organizations can enhance transparency and credibility, rebuilding trust with the public. Additionally, the study highlights the critical role of media in influencing perceptions and decision-making during crises, emphasizing the importance of responsible and ethical reporting. Understanding the intricate interplay between MCS and OI can inform better crisis management strategies and improve how organizations respond to and recover from incidents, ultimately benefiting society by promoting more accountable and responsible corporate behaviour.

This study’s distinctness lies in its innovative exploration of MCS, which transcends traditional methodologies that focus narrowly on front or backstage aspects of OI and often adhere to predetermined MCS practices. It underscores the importance of concurrently addressing both the front- and backstage audiences in managing the embarrassment caused by identity discrepancies and restoration. The research uncovers multifaceted interdependencies within MCS and OI, and these extend beyond simplistic relationships and emphasize the complex nature of identity restoration management.

The purpose of this paper is to propose and validate a robust industrial control system. The aim is to design a Multivariable Proportional Integral controller that accommodates multiple responses while considering the process's control and noise parameters. In addition, this paper intended to develop a multidisciplinary approach by combining computational science, control engineering and statistical methodologies to ensure a resilient process with the best use of available resources.

Taguchi's robust design methodology and multi-response optimisation approaches are adopted to meet the research aims. Two-Input-Two-Output transfer function model of the distillation column system is investigated. In designing the control system, the Steady State Gain Matrix and process factors such as time constant (t) and time delay (?) are also used. The unique methodology is implemented and validated using the pilot plant's distillation column. To determine the robustness of the proposed control system, a simulation study, statistical analysis and real-time experimentation are conducted. In addition, the outcomes are compared to different control algorithms.

Research indicates that integral control parameters (K_i) affect outputs substantially more than proportional control parameters (K_p). The results of this paper show that control and noise parameters must be considered to make the control system robust. In addition, Taguchi's approach, in conjunction with multi-response optimisation, ensures robust controller design with optimal use of resources. Eventually, this research shows that the best outcomes for all the performance indices are achieved when Kp11 = 1.6859, Kp12 = −2.061, Kp21 = 3.1846, Kp22 = −1.2176, Ki11 = 1.0628, Ki12 = −1.2989, Ki21 = 2.454 and Ki22 = −0.7676.

This paper provides a step-by-step strategy for designing and validating a multi-response control system that accommodates controllable and uncontrollable parameters (noise parameters). The methodology can be used in any industrial Multi-Input-Multi-Output system to ensure process robustness. In addition, this paper proposes a multidisciplinary approach to industrial controller design that academics and industry can refine and improve.

In general, the existing compressor design methods require abundant knowledge and inspiration. The purpose of this study is to identify an intellectual design optimization method that enables a machine to learn how to design it.

The airfoil design process was solved using the reinforcement learning (RL) method. An intellectual method based on a modified deep deterministic policy gradient (DDPG) algorithm was implemented. The new method was applied to agents to learn the design policy under dynamic constraints. The agents explored the design space with the help of a surrogate model and airfoil parameterization.

The agents successfully learned to design the airfoils. The loss coefficients of a controlled diffusion airfoil improved by 1.25% and 3.23% in the two- and four-dimensional design spaces, respectively. The agents successfully learned to design under various constraints. Additionally, the modified DDPG method was compared with a genetic algorithm optimizer, verifying that the former was one to two orders of magnitude faster in policy searching. The NACA65 airfoil was redesigned to verify the generalization.

It is feasible to consider the compressor design as an RL problem. Trained agents can determine and record the design policy and adapt it to different initiations and dynamic constraints. More intelligence is demonstrated than when traditional optimization methods are used. This methodology represents a new, small step toward the intelligent design of compressors.

The purpose of this paper is to implement a closed loop regulated bidirectional DC to DC converter for an application in the electric power system of more electric aircraft. To provide a consistent power supply to all of the electronic loads in an aircraft at the desired voltage level, good efficiency and desired transient and steady-state response, a smart and affordable DC to DC converter architecture in closed loop mode is being designed and implemented.

The aircraft electric power system (EPS) uses a bidirectional half-bridge DC to DC converter to facilitate the electric power flow from the primary power source – an AC generator installed on the aircraft engine’s shaft – to the load as well as from the secondary power source – a lithium ion battery – to the load. Rechargeable lithium ion batteries are used because they allow the primary power source to continue recharging them whenever the aircraft engine is running smoothly and because, in the event that the aircraft engine becomes overloaded during takeoff or turbulence, the charged secondary power source can step in and supply the load.

A novel nonsingular terminal sliding mode voltage controller based on exponential reaching law is used to keep the load voltage constant under any of the aforementioned circumstances, and its performance is contrasted with a tuned PI controller on the basis of their respective transient and steady-state responses. The former gives a faster and better transient and steady-state response as compared to the latter.

This research gives a novel control scheme for incorporating an auxiliary power source, i.e. rechargeable battery, in more electric aircraft EPS. The battery is so implemented that it can get regeneratively charged when primary power supply is capable of handling an additional load, i.e. the battery. The charging and discharging of the battery is carried out in closed loop mode to ensure constant battery terminal voltage, constant battery current and constant load voltage as per the requirement. A novel sliding mode controller is used to improve transient and steady-state response of the system.