There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

This paper presents a detailed description of finite control set model predictive control (FCS-MPC) applied to power converters Several key aspects related to this methodology are, in depth, presented and compared with traditional power converter control techniques, such as linear controllers with pulsewidth-modulation-based methods The basic concepts, operating principles, control diagrams, and results are used to provide a comparison between the different control strategies The analysis is performed on a traditional three-phase voltage source inverter, used as a simple and comprehensive reference frame However, additional topologies and power systems are addressed to highlight differences, potentialities, and challenges of FCS-MPC Among the conclusions are the feasibility and great potential of FCS-MPC due to present-day signal-processing capabilities, particularly for power systems with a reduced number of switching states and more complex operating principles, such as matrix converters In addition, the possibility to address different or additional control objectives easily in a single cost function enables a simple, flexible, and improved performance controller for power-conversion systems

Model Predictive Control—A Simple and Powerful Method to Control Power Converters

Predictive control is a very wide class of controllers that have found rather recent application in the control of power converters. Research on this topic has been increased in the last years due to the possibilities of today's microprocessors used for the control. This paper presents the application of different predictive control methods to power electronics and drives. A simple classification of the most important types of predictive control is introduced, and each one of them is explained including some application examples. Predictive control presents several advantages that make it suitable for the control of power converters and drives. The different control schemes and applications presented in this paper illustrate the effectiveness and flexibility of predictive control.

Predictive Control in Power Electronics and Drives

This paper presents a predictive current control method and its application to a voltage source inverter. The method uses a discrete-time model of the system to predict the future value of the load current for all possible voltage vectors generated by the inverter. The voltage vector which minimizes a quality function is selected. The quality function used in this work evaluates the current error at the next sampling time. The performance of the proposed predictive control method is compared with hysteresis and pulsewidth modulation control. The results show that the predictive method controls very effectively the load current and performs very well compared with the classical solutions

Predictive Current Control of a Voltage Source Inverter

This paper presents a simplified mathematical model for the brushless DC motor The steady state and the dynamic performance for this motor is well studied and demonstrated in this paper for different loading conditions Also, an efficient speed control strategy is developed and discussed, and the outcome of this control strategy is proved by digital simulation results

A Simple and Effective Speed Control Strategy for the Brushless DC Motor

This paper presents a novel multi-functional component which combines the features of heat sink and magnetic device in the power converters. Inspired by the functional integration concept, the proposed heat sink component is well designed in order to also serve as an inductor. With the modified winding and magnetic circuit design, the inductance can accommodate the requirement of power converter without increasing the DC condition loss. This proposed heat sink-inductor device can significantly save the total volume of power module and improve the thermal performance at the meanwhile. In the studied point of load power module, the total volume is decreased by 40% and the temperature of voltage regulation IC is decreased by 14°C.

A power converter integration approach with a multi-functional heat sink shaped inductor

The control strategy of the DC-to-DC switching converters is studied to obtain the switching regulators with zero-voltage regulation. A novel control strategy, the function control, is presented for the DC-to-DC switching convertors to achieve this objective. The control law and the corresponding feedbacks are derived directly from the equations governing the switching converters. With the function control strategy presented, the switching regulators become robust, i.e. the output is independent of the disturbances from either the supply voltage or the load and exhibit other advantages. The strategy is applicable to all the four basic PWM converters, i.e. buck, boost, buck-boost and Cuk. The analysis is confirmed by experiments and computer simulations. >

Function control: a novel strategy to achieve improved performance of the DC-to-DC switching regulators

Although a single-stage off-line LED driver can achieve low cost and high efficiency, the notorious double-line-frequency flicker issue with a single-stage LED driver limits its usage in high-quality lighting applications. To solve lighting flicker, multiplexing operation is proposed in this paper. One switching cycle is further divided into two portions, namely phase one and phase two, which produces a main output voltage and an opposite ripple voltage. The main and the opposite ripple voltage are connected in series to form the LED voltage, which is a DC because of ripple cancellation. Therefore, a DC LED current can be produced and achieves flicker-free LED driving performance. A 7.5W experimental prototype had been built and tested to verify the design concept.

A Multiplexing Off-Line LED Driver Achieves High Power Factor and Flicker-Free Operation

A multi-stage, multi-level DC-DC step-down converter includes a first stage and a second stage having two identical cells connected in parallel. The first stage includes an input capacitor, four switches, and one flying capacitor. The two cells of the second stage each include four switches and one flying capacitor, and an output filter. The cells of the second stage are driven at half the switching frequency of the input stage, and provides a step-down ratio of 4:1. A third stage having four cells may be added to achieve a step-down ratio of 8:1, a fourth stage having eight cells may be added to achieve a step-down ration of 16:1, etc., each additional stage including a doubling of the number of cells connected in parallel, with all cells being substantially identical, and each stage operating at a further reduced fraction of the switching frequency. Embodiments are particularly suitable for applications such as a 48V intermediate bus architecture for servers and datacenters.

Yan-Fei Liu

Papers

A Simple and Effective Speed Control Strategy for the Brushless DC Motor

A power converter integration approach with a multi-functional heat sink shaped inductor

Function control: a novel strategy to achieve improved performance of the DC-to-DC switching regulators

A Multiplexing Off-Line LED Driver Achieves High Power Factor and Flicker-Free Operation

Zero inductor voltage converter topology with improved switch utilization