In the first part of this paper, three-phase power factor correction (PFC) rectifier topologies with sinusoidal input currents and controlled output voltage are derived from known single-phase PFC rectifier systems and/or passive three-phase diode rectifiers. The systems are classified into hybrid and fully active pulsewidth modulation boost-type or buck-type rectifiers, and their functionality and basic control concepts are briefly described. This facilitates the understanding of the operating principle of three-phase PFC rectifiers starting from single-phase systems, and organizes and completes the knowledge base with a new hybrid three-phase buck-type PFC rectifier topology denominated as Swiss Rectifier. Finally, core topics of future research on three-phase PFC rectifier systems are discussed, such as the analysis of novel hybrid buck-type PFC rectifier topologies, the direct input current control of buck-type systems, and the multi-objective optimization of PFC rectifier systems. The second part of this paper is dedicated to a comparative evaluation of four rectifier systems offering a high potential for industrial applications based on simple and demonstrative performance metrics concerning the semiconductor stresses, the loading and volume of the main passive components, the differential mode and common mode electromagnetic interference noise level, and ultimately the achievable converter efficiency and power density. The results are substantiated with selected examples of hardware prototypes that are optimized for efficiency and/or power density.

The Essence of Three-Phase PFC Rectifier Systems—Part II

In this paper, three-phase PFC rectifier topologies with sinusoidal input currents and controlled output voltage are derived from known single-phase PFC rectifier systems and/or passive three-phase diode rectifiers. The systems are classified into hybrid and fully active PWM boost-type or buck-type rectifiers, and their functionality and basic control concepts are briefly described. This facilitates the understanding of the operating principle of three-phase PFC rectifiers starting from single-phase systems, and organizes and completes the knowledge base with a new hybrid three-phase buck-type PFC rectifier topology denominated as Swiss Rectifier. In addition, analytical formulas for calculating the current stresses on the power semiconductors of selected topologies are provided, and rectifier systems offering a high potential for industrial applications are comparatively evaluated concerning the semiconductor stresses, the loading and volume of the main passive components, and the DM and CM EMI noise level. Finally, core topics of future research on three-phase PFC rectifier systems are discussed, such as the analysis of novel hybrid bucktype PFC rectifier topologies, the direct input current control of bucktype systems, the multi-objective optimization of PFC rectifier systems concerning efficiency and power density, and the investigation of the system performance sensitivity to semiconductor and passive components technology.

The essence of three-phase PFC rectifier systems

The digital control of a three-phase three-switch buck-type rectifier system is analyzed in this paper. Three main sources of time delays in the control loop can be identified for the implementation on a digital signal processor (DSP): 1) the delay time due to the sampling of the control quantities; 2) the one due to the calculation time of the DSP; and 3) the one due to the sample-and-hold function of the pulsewidth modulator. Using the buck-type system as an example, the influence of the time delay on the stability of the inner current control loop is discussed, and two prediction methods for time-delay compensation, i.e., a linear prediction and the Smith prediction, are comparatively evaluated. The control performance and the effect of the delay times and the prediction methods are shown by simulation results and through measurements on a 5-kW prototype.

Comparison of Prediction Techniques to Compensate Time Delays Caused by Digital Control of a Three-Phase Buck-Type PWM Rectifier System

In a power converting apparatus which converts AC power into DC power, an inverter circuit including at least one series-connected single-phase inverter is connected in a downstream of a stage in which an AC input is rectified in series therewith. In the downstream stage of the inverter circuit, there are provided a smoothing capacitor connected via a rectifier diode and a short-circuiting switch for bypassing the smoothing capacitor. The short-circuiting switch is set to an ON state only in each of short-circuiting phase ranges of which midpoint matches each of zero-crossing phases and an output of the inverter circuit is controlled by using a current command so that a DC voltage of the smoothing capacitor follows a target voltage and an input power factor is improved.

Power converting apparatus

A power conversion device includes a power switching circuit that supplies AC voltages generated between switching elements operating as upper arms and switching elements operating as lower arms, and a control circuit that generates and supplies to the driver circuit signals for controlling the switching operation of the switching elements by a PWM method in a first operational region in which frequency of an AC power to be outputted is low, and that generates and supplies to the driver circuit signals for controlling the switching operation of the switching elements at timings based upon the phase of the AC power to be outputted in an operational region in which the frequency of the AC power to be outputted is higher than in the first operational region.

Power Conversion Device

Novel hybrid 12-pulse line interphase transformer (LIT) rectifier systems with integrated single-switch or two-switch boost-type output stage that ensure a constant output voltage independent of mains and load conditions are proposed for supplying actuators of future more electric aircraft. The principle of operation, the dimensioning, and the system control are discussed. The theoretical considerations are experimentally confirmed for a 10 kW laboratory prototype. Finally, the single-and the two-switch system are comparatively evaluated concerning the level of input current ripple, power factor, and overall efficiency.

Novel hybrid 12-pulse boost-type rectifier with controlled output voltage

Provided is an uninterruptible power supply system The uninterruptible power supply system includes a power supply unit including a power supply circuit converting alternating current power into direct current voltage to be supplied to a load apparatus The uninterruptible power supply system includes a battery unit including a battery circuit The battery circuit stores direct current power and discharges the direct current power to generate direct current voltage to be supplied to the load apparatus The uninterruptible power supply system includes a rack in which each of the power supply unit and the battery unit is mounted

Uninterruptible power supply system

A novel integrated EMI filter structure is proposed in this paper, based on FML foils. It integrates common mode inductors and differential mode capacitors and inductors into a single unit. A novel interleaved flexible multi-layer (FML) foil structure is proposed to overcome the difficulty of enlarging the DM capacitance. A prototype is constructed based on this concept and was put into a front-end converter to replace a discrete EMI filter. Testing result presented.

An integrating structure of EMI filter based on interleaved flexible multi-layer (FML) foils

PROBLEM TO BE SOLVED: To provide a cascade device in which a normally ON type switching element and a normally OFF type switching element are connected in series, the cascade device which makes the switching elements safely switch at high speeds without exceeding breakdown voltages of the switching elements. SOLUTION: The normally ON type switching element and normally OFF type switching element are connected and a driving circuit is connected to the normally OFF type switching element to constitute the cascade device capable of normally OFF type operation. Then a series circuit of a voltage clamping means and a diode is connected between the drain (or collector) and gate (or base) of the normally OFF type switching element. COPYRIGHT: (C)2007,JPO&INPIT

Compound type semiconductor device

PROBLEM TO BE SOLVED: To reduce harmonics of input current in a step-up AC/DC conversion circuit. SOLUTION: In the step-up AC/DC conversion circuit, reactors 3 to 5 are inserted into a connection point between an AC power source 1 and diode rectifying circuits 11 to 16, a switching element 23 is connected between the output terminals of the diode rectifying circuits, and a series circuit formed of a capacitor 32 and a diode 19 is connected in parallel with the switching element, making both ends of the capacitor 32 DC output. The series circuits formed of diodes 17, 18 and switching elements 21, 22 are mutually connected in parallel with a capacitor 31, a bridge circuit wherein the connection point between the diode 17 and the switching element 21 is made as an input terminal while the connection point between the diode 18 and the switching element 22 is made as an output terminal is inserted between the diode rectifying circuits 11 to 16 and the switching element 23 to constitute the AC/DC conversion circuit. COPYRIGHT: (C)2008,JPO&INPIT

Kazuaki Mino

Papers

Novel hybrid 12-pulse boost-type rectifier with controlled output voltage

Uninterruptible power supply system

An integrating structure of EMI filter based on interleaved flexible multi-layer (FML) foils

Compound type semiconductor device

Ac/dc conversion circuit