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

Ripple cancellation LED driver can achieve flicker-free LED driving while maintaining high power factor, high efficiency, and low component cost. It is a very competitive solution compared to a conventional single-stage or two-stage LED driver design. In this paper, a primary-side-controlled ripple cancellation LED driver has been proposed. The voltages of the proposed LED driver are sensed at the primary side by transformer sensing windings. The LED current is also obtained by sensing the primary-side switching current. The entire control circuit is built on the primary side. All the advantages from the existing ripple cancellation LED drivers are maintained while achieving the primary-side control. Based on the proposed circuit, a potential integrated primary-side controller can be designed, which can significantly reduce the component cost and design complexity. A 30-W, 50-V, 0.6-A experimental prototype with a universal input voltage range has been built to verify the proposed LED driver.

A Single-Stage Primary-Side-Controlled Off-line Flyback LED Driver With Ripple Cancellation

The Class-E DC-DC converters with half-wave and full-wave controlled current rectifiers are proposed. Zero voltage switching for all the switches can be maintained from full load to no load. The switching frequency is constant. When the load current changes from maximum to zero, the output voltage can be kept constant by regulating the conducting angle of the rectifier switch. The operation of the new converters is analyzed and the zero voltage switching characteristic has been demonstrated. The current gain of the circuit versus the conducting angle has been presented.

New class-E DC-to-DC converter topologies with constant switching frequency

In this paper, the concept of the adaptive current source drivers (CSDs) is proposed for the high-frequency synchronous buck converters. Compared to the previous CSD circuits, the adaptive CSD can achieve adjustable drive current and drive voltage according to different load condition. The benefit is that higher drive current and voltage lead to lower switching loss and conduction loss when the load current increases. Therefore, the adaptive CSD is able to realize optimal design to reduce the switching loss, the gate drive loss, and the conduction loss in a wide load range. It should be noted that the adaptive concept is suitable for both the continuous and discontinuous CSDs regardless the drive circuit topologies. Through investigating the CSD circuits, one simple method to achieve the adaptive drive current based on the adaptive voltage is proposed. A 12 V input, 1.3 V output, and 1-MHz synchronous buck converter with the continuous and discontinuous CSDs was built, respectively, to verify the advantages of the proposed adaptive concept and efficiency improvement.

Adaptive Current Source Drivers for Efficiency Optimization of High-Frequency Synchronous Buck Converters

In this paper, a digital charge balance controller is presented which is capable of controlling a Buck converter and an auxiliary circuit to achieve an excellent unloading transient response. The auxiliary circuit significantly reduces the voltage overshoot caused by an unloading transient while the digital charge balance controller reduces the settling time of the converter. The controller is capable of implementing load-line regulation and yields a smooth transition from one loading condition to another. Simulation and experimental verification is performed and demonstrates significant transient improvement over previously-proposed solutions.

Digital charge balance controller with an auxiliary circuit for superior unloading transient performance of Buck converters

A new single-stage converter is proposed in this paper. The converter operates with fixed switching frequency, and with a continuous input current that is sinusoidal and in phase with the input voltage. This is in contrast with most other single-stage converters, which are either resonant converters or must operate with a discontinuous input current. All converter switches operate with soft-switching due to a simple auxiliary circuit that is used for only a small fraction of the switching cycle. In the paper, the operation of the converter is explained and analyzed, and design guidelines are given. The feasibility of the converter is shown with results obtained from an experimental prototype.

Yan-Fei Liu

Papers

A Single-Stage Primary-Side-Controlled Off-line Flyback LED Driver With Ripple Cancellation

New class-E DC-to-DC converter topologies with constant switching frequency

Adaptive Current Source Drivers for Efficiency Optimization of High-Frequency Synchronous Buck Converters

Digital charge balance controller with an auxiliary circuit for superior unloading transient performance of Buck converters

A single-stage zero-voltage switched PWM full-bridge converter with power factor correction