THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The Design and Analysis of Experiments

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

A method and apparatus of creating a dynamically reconfigurable energy source comprised of individual, isolated, controllable energy modules, supported by software to measure and manage the energy modules and facilitate the reconfiguration, where the platform consisting of hardware, based upon an inverted H-Bridge circuitry, in combination with software which allows for real-time management, control, and configuration of the modules and uses a combination of software algorithms and localized electronic switches, to achieve a performance and functionality of the invention matching, or exceeding, traditional large, heavy, and expensive power electronics-based products used for charging, energy storage management, power inverting, and motor or load control

Method and apparatus for creating a dynamically reconfigurable energy storage device

Driving solutions for power semiconductor devices are experiencing new challenges since the emerging wide bandgap power devices, such as silicon carbide (SiC), with superior performance become commercially available. Generally, high switching speed is desired due to the lower switching loss, yet high $dv/dt$ and $di/dt$ can result in elevated electromagnetic interference (EMI) emission, false-triggering, and other detrimental effects during switching transients. Active gate drivers (AGDs) have been proposed to balance the switching losses and the switching speed of each switching transient. The review of the in-existence AGD methodologies for SiC devices has not been reported yet. This review starts with the essence of the slew rate control and its significance. Then, a comprehensive review categorizing the state-of-the-art AGD methodologies is presented. It is followed by a summary of the AGDs control and timing strategies. In this work, using AGD to reduce the EMI noise of a 10-kV SiC MOSFET system is reported. This work also highlights other capabilities of AGDs, including reliability enhancement of power devices and rebalancing the mismatched electrical parameters of parallel- and series-connected devices. These application scenarios of AGDs are validated via simulation and experimental results.

A Review of Switching Slew Rate Control for Silicon Carbide Devices Using Active Gate Drivers

A switching power-supply apparatus and a switching power supply circuit in which a feedback signal is input from a feedback circuit to a feedback terminal of a switching control IC includes a capacitor and a Zener diode connected between the feedback terminal and a ground terminal. The Zener diode is a selectively connected external circuit. A voltage of the feedback terminal during an overcurrent operation changes depending on whether or not the external circuit is present. A return/latch determination circuit detects the voltage of the feedback terminal to switch between an automatic return system and a latch system in an overcurrent operation state.

Switching control circuit and switching power supply apparatus

In accordance with an embodiment, a circuit includes voltage supply terminals configured to provide an AC output voltage, at least two converter units, and a control circuit. Each converter unit includes input terminals configured to be connected to an electrical charge storage unit, output terminals, and a switch arrangement connected between the input and output terminals. The switch arrangement is configured to receive a control signal, and provide an output voltage having a duty-cycle dependent on the control signal. The control circuit is configured to provide a set of parameter sets that are dependent on a desired output voltage waveform, define a duty-cycle, and generate the control signals for the at least two converter units such that one parameter set is selected from the set of parameter sets is assigned to one converter unit, and the assignment of parameter sets to the converter stages varies over time.

Circuit arrangement including a multi-level converter

A circuit arrangement includes a half-bridge with a high-side switch and a low-side switch, each switch including a control terminal and a load path. The load paths of the high-side switch and the low-side switch are coupled in series between a terminal for a supply potential and a terminal for a reference potential a high-side driver operable to provide a high-side drive signal received at the control terminal of the high-side switch. The high-side driver includes supply terminals a charge storage device coupled between the supply terminals of the high-side driver. A control circuit includes a charging circuit, a switching element and a drive circuit operable to switch on the switching element dependent on at least one operation parameter of the circuit arrangement.

Circuit arrangement for driving transistors in bridge circuits

There is a growing need for motor drives with improved EMC in various automotive and industrial applications. An often referenced approach to reduce EME is to change the shape of the switching signal to reduce the EMI caused by the voltage and current transitions. This requires very precise gate control of the power MOSFET to achieve better switching behaviour and lower EME without a major increase in switching losses. In order to find an optimal trade-off, this work utilizes a monolithic current mode gate driver with a variable output current that can be changed within 10ns. With this driver, measurements with different gate current profiles were taken. The di/dt transition was confirmed to be as important as the dv/dt transition in the power MOSFET. As a result of the improved switching behavior the emissions were reduced by up to 20dB between 7MHz and 60MHz with a switching loss that is 52% lower than with a constantly low gate current.

EMC and switching loss improvement for fast switching power stages by di/dt, dv/dt optimization with 10ns variable current source gate driver

Beschrieben wird eine Schaltungsanordnung mit einem Mehrstufenwandler, der aufweist: Spannungsversorgungsklemmen (11, 12), die dazu ausgebildet sind, eine Ausgangswechselspannung (Vac) bereitzustellen; wenigstens zwei Wandlerstufen (C1, C2, Cn), wobei jede Wandlerstufe Eingangsklemmen (P1', M1', ..., Pn', Mn'), die dazu ausgebildet sind, an eine elektrische Ladungsspeichereinheit (B1, B2, Bn) angeschlossen zu werden, Ausgangsklemmen (P1, M1, ..., Pn, Mn) und eine Schalteranordnung (H1, H2), die zwischen die Eingangsklemmen und Ausgangsklemmen (P1, M1, ..., Pn, Mn) gekoppelt ist, aufweist, wobei die Schalteranordnung dazu ausgebildet ist, ein Steuersignal (S1, S2, Sn) zu empfangen und eine Ausgangsspannung (V1, V2, Vn) mit einem Tastverhaltnis abhangig von dem Steuersignal (S1, S2, Sn) an den Spannungsversorgungsklemmen (11, 12) bereitzustellen, wobei die wenigstens zwei Wandlerstufen (C1, C2, Cn) in Reihe zwischen die Spannungsversorgungsklemmen (11, 12) geschaltet sind; und eine Steuerschaltung (20).

Schaltungsanordnung mit einem Mehrstufenwandler

Modern power transistors are able to switch at very high transition speed, which can cause EMC violations and overshoot. This is addressed by a gate driver with variable gate current, which is able to control the transition speed. The key idea is that the gate driver can influence the di/dt and dv/dt transition separately and optimize whichever transition promises the highest improvement while keeping switching losses low. To account for changes in the load current, supply voltage, etc., a control loop is required in the driver to ensure optimized switching. In this paper, a efficient control scheme for an automotive gate driver with variable output current capability is presented. The effectiveness of the control loop is demonstrated for a MOSFET bridge consisting of OptiMOS-T2™devices with a total gate charge of 39nC. This bridge setup shows dv/dt transitions between 50 to 1000ns, depending on driving current. The driver is able to switch between gate current levels of 1 to 500mA in 10/15ns (rising/falling transition). With the implemented control loop the driver is measured to significantly reduce the ringing and thereby reduce device stress and electromagnetic emissions while keeping switching losses 52% lower than with a constant current driver.

Benno Koeppl

Papers

Circuit arrangement including a multi-level converter

Circuit arrangement for driving transistors in bridge circuits

EMC and switching loss improvement for fast switching power stages by di/dt, dv/dt optimization with 10ns variable current source gate driver

Schaltungsanordnung mit einem Mehrstufenwandler

10ns Variable current gate driver with control loop for optimized gate current timing and level control for in-transition slope shaping