ONE OF MY DUTIES at Power Electronics Technology is to set up the monthly articles. Usually we try to stick with our editorial calendar, which is a list of subjects from month-to-month for the year. In July we scheduled Non-Silicon Power Semiconductors, Modeling /Simulation and Digital Power. In addition, we usually include other article subjects of interest to our readers.
Therefore, in July, Johan Strydom of Efficient Power Conversion (EPC) will describe the use of GaN in isolated converters. Strydom will test an eGaN™ FET-based isolated converter against a state of the art, commercially available silicon-based solution in the 1/8th brick form factor designed for 48 V telecom applications with a 12 V output. Testing will look at efficiency and output power capability and the results will be compared against existing power MOSFET based solutions.
Strydom's article will join Tim McDonald and Mike Briere's article (International Rectifier) that will present their view of the GaN landscape.
Another semiconductor article will be presented by Deepak Veereddy and Eric Leiser of GeneSiC. They will describe a 1200 V/100 A Si IGBT/SiC diode copack. The company's recently launched 1200 V IGBT copack integrates the Optimal Punch Through (OPT) Si IGBTs with best-in-class SiC Schottky diodes. These copacks reduce overall switching losses by about 28%, compared with the current state-of-the-art Si IGBT modules.
Wireless Power transfer will also be covered in July, from an IC and a magnetics viewpoint. Wireless power allows the transmission of electrical energy from a power source to an electrical load without interconnecting wires. This process is useful where interconnecting wires are inconvenient, hazardous, or impossible. Use of wireless power involves the magnetic coupling of conductors configured so that the change in current flow through one conductor transfers a voltage in another conductor through electromagnetic induction. The amount of inductive coupling between two conductors is determined by their mutual inductance.
The IC viewpoint will be covered by a description of a wireless Power Receiver that complements an existing Power Transmitter. These ICs use a combination of analog and digital circuits. Both ICs comply with Wireless Power Consortium (WPC) Qi Standard Version 1.0.2 (April 2011) for wireless power transfer based on near field magnetic induction between planar coils. Wireless power transfer employs a Power Transmitter with a primary coil that creates a magnetic field on a charging pad. When placed on the charging pad, a secondary coil that has an associated wireless Power Receiver converts the induced magnetic field into a dc output voltage. The wireless Power Receiver IC has full-bridge synchronous rectification, voltage conditioning and wireless power control.
The simulation/modeling article will cover a SPICE model that guarantees simulation for nonlinear circuits. The article, by Lawrence Meares, president of Intusoft, will describe a new “STATESET” SPICE model used in super-fast average modeling for power supplies and related control systems results in guaranteed DC convergence for nonlinear circuits. It eliminates the historic multiple stable operating-point solutions via SPICE's “nodeset” statement, by creating a new circuit branch in which the element output is initialized during the entire DC operating point calculation. Once calculated, the input of the STATESET branch connects to its output, so AC and transient analyses can proceed accurately.
Not an editorial calendar subject, but an interesting one, will be a description of a Power over Ethernet (PoE) system that employs a Power Source Equipment (PSE) controller that sends power and data to a Powered Device (PD). It uses a pair of ICs that combine to produce a 12-port PSE controller that creates an isolated environment consistent with PoE specifications. The 12 independent PSE ports send power and data to the Powered Device (PD). In contrast with traditional approaches, it is a simpler, lower component count design, reducing board space and lowering system costs.
