Abstract: A system controller for position controlling a photovoltaic (PV) panel in a PV system including a power sensor sensing output power (P), and a motor for positioning the PV panel. The system controller includes a computing device having memory that provides motor control signals and implements an iterative adaptive control (IAC) algorithm stored in the memory for adjusting an angle of the PV panel. The IAC algorithm includes an iterative relation that relates P at current time k (P(k)), its elevation angle at k (?s (k)), P after a next step (P(k+1)) and its elevation angle at k+1 (?s (k+1)). The IAC algorithm generates a perturbed power value P(k+1) to provide a power perturbation to P(k), and calculates a position angle ?S (k+1) of the PV panel using the perturbed power value. The motor control signals from the computing device cause the motor to position the PV panel to achieve ?S (k+1).

Abstract: A method for balancing power distribution in a direct current to direct current (DC to DC) power-conversion system is provided. The power-conversion system includes a plurality of channels that are connected to a load. The channels are also connected to corresponding power sources. The method, at a first channel, includes obtaining a first power, which is the maximum power of the power source connected to the first channel. Further, the method includes computing a reference power based on the power output of the channels. Furthermore, the method includes outputting the reference power when the first power is greater than or equal to the reference power, and outputting the first power when the first power is less than the reference power.

Abstract: A method for balancing power distribution in a direct current to direct current (DC to DC) power-conversion system is provided. The power-conversion system includes a plurality of channels that are connected to a load. The channels are also connected to corresponding power sources. The method, at a first channel, includes obtaining a first power, which is the maximum power of the power source connected to the first channel. Further, the method includes computing a reference power based on the power output of the channels. Furthermore, the method includes outputting the reference power when the first power is greater than or equal to the reference power, and outputting the first power when the first power is less than the reference power.

Abstract: Methods, systems and apparatus for a controller for fast transient response, the controller including a linear compensation circuit for controlling output voltage during steady state operation and a non-linear control circuit to generate a non-linear signal during transient periods, only a first pulse of the non-linear signal is injected during each transient period. The combination linear and non-linear control provides stability and reduces delay times for fast transient response. The non-linear control circuit includes a step up and a step down non-linear control circuit for producing the non-linear signal with a short delay time when the load voltage is less or greater than the reference voltage. An embodiment includes an adaptive circuit or generating a current signal dependent on the load current, the current signal is combined with the output voltage to reduce the difference between the reference and output voltages.

Abstract: A DC-to-DC converter having a transformer with a primary and a tapped secondary, two serial output filter inductors connected parallel with the secondary, a center output filter inductor connected between the secondary tap and serial output inductors, two serially connected switches connected in parallel with the two output inductors for receiving a signal to control operation of the switches during steady state and an output load connected between the serial connection of the serial output inductors and serial switching devices. The transformer primary side connected with double-ended primary-side topologies. The transformer secondary and output filers configured to form a current tripler rectifier, current quadtupler rectifier or current N-tuper rectifier.

Abstract: Interactive electronic book operating systems and methods for displaying and allowing customization of content of scientific, engineering and other technical and professional digital books. The systems and methods allow for a single screen for displaying digital books covering scientific and technical topics having a classical look and feel on operating platforms(such as portable laptops, desktops, and small handheld displays) that are capable of running the Java Virtual Machine. The display screen can include icon toolbars about the screen and/or directly on the screen to manipulate the pages and content of the digital book.

Abstract: Apparatus, methods, system and devices for providing a high efficiency parallel post regulator for a wide range input DC/DC converter. The wide input range DC/DC converter achieves zero-voltage-switching in the primary side switches in full range load due to 0.5 duty cycle of the operation at full load. The DC/DC converter reduces voltage stresses across main rectifiers, has a smaller conduction losses compared with conventional post regulators and the requirement of input and output filters is significantly reduced due to the filtered waveforms produced.

Abstract: A direct current to direct current (DC-to-DC) converter having an active transient voltage compensator (ATVC) coupled with the DC-to-DC converter output terminal to improve a fast transient response of the DC-to-DC converter. The active transient voltage compensator compensates the DC output only during transient operation The ATVC includes a transformer for reducing the ATVC current stresses to improve the compensator efficiency and injecting, absorbing high slew rate current, and a controller circuit for controlling ATVC operation in steady state and normal operation in transients. During step-up load the ATVC operates as a buck converter and during step-down load, the ATVC operates as a boost converter while the main converter operates at low switching frequency for good efficiency.

Abstract: Apparatus, methods system and devices for using alternated duty cycle control to achieve soft-switching for at least one switch of the two half-bridge switches. When soft-switching can be only achieved for one switch, alternated duty cycle control alternates the soft-switching between the two switches so that each switch is soft-switched during half of the time and hard-switched during the other half, keeping equal power losses distribution between the switches. When alternated duty cycle control is used, any asymmetry in the duty cycle does not cause asymmetric components stresses or transformer DC bias.

Abstract: A power converter includes a first transformer that has a primary winding and a secondary winding. The secondary winding is coupled to a first secondary side. A second transformer has a primary winding and a secondary winding. The secondary winding is coupled to a second secondary side. The primary windings of the first and second transformers are coupled in parallel to a primary side through respective windings of a transformer that has inverse coupled windings. The secondary windings of the first and second transformer are coupled in parallel. The second secondary side is interleaved with the first secondary side.

Abstract: Apparatus, methods system and devices for using alternated duty cycle control to achieve soft-switching for at least one switch of the two half-bridge switches. When soft-switching can be only achieved for one switch, alternated duty cycle control alternates the soft-switching between the two switches so that each switch is soft-switched during half of the time and hard-switched during the other half, keeping equal power losses distribution between the switches. When alternated duty cycle control is used, any asymmetry in the duty cycle does not cause asymmetric components stresses or transformer DC bias.

Abstract: An inverter for use in connecting a DC power source to the utility grid includes a single DC-DC conversion stage, maximum (source) power tracking, and current control based on feed-forward compensation as a function of an input power commanding voltage, rectified utility line voltage, and either a scaled and squared inverse or a scaled inverse of RMS utility line voltage.

Abstract: A coupled-inductor current-doubler topology for a power converter has first and second rectifiers and first and second coupled inductors. Each coupled inductor has a main inductor inductively coupled with a secondary inductor. The secondary inductor of the first coupled inductor is coupled in series with one of the first and second rectifiers and the secondary inductor of the second coupled inductor coupled in series with the other one of the first and second rectifiers.

Abstract: A power converter uses a control method to optimize efficiency by dynamically optimizing a controlled parameter. A change in efficiency of the converter after changing at least one controlled parameter is determined. The direction of change in efficiency of the converter is compared to a direction of the change in the controlled parameter. The controlled parameter is changed in a positive direction when the direction in the change in the efficiency of the converter and the direction of the change in the controlled parameter are the same and changed in a negative direction when the direction in the change in the efficiency of the converter and the direction of the change in the controlled parameter are opposite. The controlled parameters may include dead time between turn-on and turn-off and between turn-off and turn-on of the primary and corresponding secondary side switches of the controller, drive voltage(s) for the switches, and intermediate bus voltages.

Abstract: A high performance single stage Power Factor Correction (PFC) converter with tight output voltage regulation and a very simple circuit to carry out those functions, which means its cost is lower than its counterparts. Two basic flyback circuits include a simple control circuit. For the hard switching circuit, only one switch is used to achieve low cost; for the soft switching scheme, one auxiliary switch is added to get higher efficiency and smaller size. There are two power flow paths, resulting in part power processed by an active switch only once to reduce the current stress and improve the efficiency. A direct current (DC) bus voltage will be limited to the peak value of input voltage. The maximum DC bus voltage will be less than 400 and a single commercial capacitor can be used for universal voltage stress under light load condition.

Abstract: A coupled-inductor current-doubler topology for a power converter has first and second rectifiers and first and second coupled inductors. Each coupled inductor has a main inductor inductively coupled with a secondary inductor. The secondary inductor of the first coupled inductor is coupled in series with one of the first and second rectifiers and the secondary inductor of the second coupled inductor coupled in series with the other one of the first and second rectifiers.

Abstract: A power converter includes a first transformer that has a primary winding and a secondary winding. The secondary winding is coupled to a first secondary side. A second transformer has a primary winding and a secondary winding. The secondary winding is coupled to a second secondary side. The primary windings of the first and second transformers are coupled in parallel to a primary side through respective windings of a transformer that has inverse coupled windings. The secondary windings of the first and second transformer are coupled in parallel. The second secondary side is interleaved with the first secondary side.

Abstract: A duty-cycle-shifted pulse-width modulation controlled half-bridge zero-voltage switching DC—DC converter has a primary side, a secondary side and a transformer coupling the primary side to the secondary side. The primary side has first and second primary switches coupled to a primary winding of the transformer and an auxiliary branch having one side coupled to a junction of the first and second primary switches and a second side coupled to common. The auxiliary branch includes a grounded auxiliary switch that is switched on when one of the first and second primary switches is on to trap leakage inductance energy of the transformer when that primary switch is turned off and thereafter switched off to release the trapped leakage inductance energy to provide a zero voltage switching condition for the other primary switch.

Abstract: A method and system of controlling half-bridge DC—DC converters to achieve Zero Voltage Switching (ZVS) for at least one of the switches. The soft-switching half-bridge DC—DC converter system includes soft-switching for all switches by adding an additional branch with a switch and a diode across the primary side of an isolation transformer and by applying a Duty-Cycle Shifted PWM Control.

Abstract: Power Factor Correction (PFC) “flyboost” cell, with a transformer having primary winding connected to input power and secondary winding connected to output rectifier, which has both functions of a flyback transformer and boost inductor. Combining the flyboost cell with DC/DC conversion cells, forms a single-stage PFC converters. Both cells share one main switch and one controller. Letting the flyboost cell operate at Discontinuous Conduction Mode, requires a simple control for high power factor. Through flyboost cell, part of output power is processed once by main switch, and is referred to as direct power transfer (DPT), which will significantly improve efficiency. The flyboost cell will automatically limit the DC bus voltage through flyboost transformer turn ratio. The converters are suitable for universal voltage applications.