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. Various embodiments also include over-voltage, over-current, under-voltage, and over-temperature protection, and a stand-by battery with its battery management control, while others adapt a multiple-channel front-end distributed power system with distributed maximum power tracking to serve as a single DC power source input to the inverter system downstream with controllers, emergency or auxiliary loads, and alternative current feedback control systems for providing an in-phase output current with respect to the utility grid voltage while absorbing maximum power available from the DC power source and minimally utilizing the stand-by battery for maximal system reliability.

Solar array inverter with maximum power tracking

A power supply including a regulation circuit that maintains an approximately constant load current with line voltage. In one embodiment, a regulation circuit includes a semiconductor switch and current sense circuitry to sense the current in the semiconductor switch. The current sense circuitry has a current limit threshold. The regulation circuit current limit threshold is varied from a first level to a second level during the time when the semiconductor switch is on. One embodiment of the regulation circuit is used in a power supply having an output characteristic having an approximately constant output voltage below an output current threshold and an approximately constant output current below an output voltage threshold.

Method and apparatus for maintaining a constant load current with line voltage in a switch mode power supply

A system and method for delivering regulated power and current to an output load has a flyback transformer having a primary winding and a secondary winding. The secondary winding delivers stored energy to the output load. An oscillator circuit is provided for generating a periodical signal. A switching circuit is coupled to the flyback transformer and the oscillator circuit for energizing the primary winding to a reference current level each cycle of the oscillator circuit. The oscillator circuit has an integrator for deriving a time integral of a voltage at the primary winding. The oscillator circuit has a peak detector coupled to the integrator for holding a peak value of the time integral. The oscillator circuit further has a ramp generator for producing a ramp signal. A comparator is provided for comparing the peak value with the ramp signal and generating the periodical signal whenever the ramp signal exceeds the peak value.

Transformer-isolated flyback converters and methods for regulating output current thereof

A PWM controller having a saw-limiter for power limit without input voltage sensing. The saw-limiter has an adder, a reference voltage, a scaler and a saw-tooth signal that is generated by the PWM oscillator. The saw-limiter produces a saw-limited voltage. The PWM controller will turn off its output when the current-sense input signal of the PWM controller is higher than the saw-limited voltage. The saw-limited voltage is equal to the reference voltage while a PWM switching period starts. After that, the amplitude of the saw-limited voltage will gradually increase until it reaches its maximum voltage. Subsequently, a saw-tooth like waveform is generated for the saw-limited voltage. The slope of the current-sense input signal is proportional to the line voltage. Therefore, a higher line voltage creates a sharp slope for the current-sense input signal, which will be restricted by a lower saw-limited voltage and produces a shorter PWM signal. The PWM signal will be turned off once the voltage of the current sense input signal is higher than the saw limited voltage. In terms of power limit, using the saw-limiter the power limit will be lower when the line voltage is higher. By properly selecting the value of the scaler an identical output power limit for the low line and high line voltage input can be achieved.

PWM controller having a saw-limiter for output power limit without sensing input voltage

A flexible photovoltaic module for converting light into electricity includes a plurality of photovoltaic cells, a wiring harness, and a connection subsystem. The plurality of photovoltaic cells are electrically interconnected to form a positive node for supplying current to a load and a negative node for receiving current from the load. The wiring harness includes a plurality of flexible electrical conductors, each electrical conductor being electrically isolated within the wiring harness. The connection subsystem is operable to selectively connect the positive node to one of the electrical conductors of the wiring harness. A plurality of flexible photovoltaic modules may be connected to form a photovoltaic array.

Flexible photovoltaic array with integrated wiring and control circuitry, and associated methods

An improved soft switched AC power distribution system for minimizing electromagnetic interference and AC losses in an AC power distribution system. The improved AC power distribution system comprises a flyback transformer comprising a primary winding and at least one intermediate secondary winding. A synchronization control circuit is connectable to the primary winding while at least one load transformer is connectable to the at least one intermediate secondary winding. The at least one load transformer connectable to the at least one intermediate secondary winding is connectable via an EMI shielded connection with controllable voltage and current rise times.

Paul S. Clayton

Papers

Method and apparatus for soft switched AC power distribution