A system and method for combining power from DC power sources. Each power source is coupled to a converter. Each converter converts input power to output power by monitoring and maintaining the input power at a maximum power point. Substantially all input power is converted to the output power, and the controlling is performed by allowing output voltage of the converter to vary. The converters are coupled in series. An inverter is connected in parallel with the series connection of the converters and inverts a DC input to the inverter from the converters into an AC output. The inverter maintains the voltage at the inverter input at a desirable voltage by varying the amount of the series current drawn from the converters. The series current and the output power of the converters, determine the output voltage at each converter.

Distributed Power Harvesting Systems Using DC Power Sources

A monitoring system and method for monitoring performance of individual powers sources in a distributed power source system A monitoring module is coupled to each of the power sources, or to each string of serially connected power sources, to monitor and collect data regarding current, voltage, temperature and other environmental factors at the power source The collected data is transmitted over a power line to a central analysis station for analysis Data collected from each source indicates malfunction or degradation at the source Comparison of data collected from adjacent sources filters for environmental factors impacting neighboring sources such as cloudy days for a solar panel Comparison of data collected from the same source at different times indicates soiling or degradation of the source with time or periodic events such as a moving shade from an adjacent building

Monitoring of Distributed Power Harvesting Systems Using DC Power Sources

Method for distributed power harvesting using DC power sources

This invention is generally concerned with power supply circuits, and more particularly, with circuits to supply power to a mains supply, such as domestic grid mains, from a photovoltaic device. A photovoltaic power conditioning circuit for providing power from a photovoltaic device to an alternating current mains power supply line, the circuit comprising: a DC input to receive DC power from said photovoltaic device; an AC output configured for direct connection to said AC mains power supply line; a DC-to-AC converter coupled to said DC input and to said AC output to convert DC power from said photovoltaic device to AC power for output onto said power supply line; and an electronic controller directly coupled to said power supply line to measure a voltage of said power supply line and a current in said supply line and to control said DC-to-AC converter responsive to said measuring.

Power supply circuits

A distributed power system including multiple DC power sources and multiple power modules. The power modules include inputs coupled respectively to the DC power sources and outputs coupled in series to form a serial string. An inverter is coupled to the serial string. The inverter converts power input from the serial string to output power. A signaling mechanism between the inverter and the power module is adapted for controlling operation of the power modules.

Safety mechanisms, wake up and shutdown methods in distributed power installations

PROBLEM TO BE SOLVED: To solve the problem in an AC output solar cell power generating system for taking out maximum power from solar cells and superimposing it on the power from an AC power supply, that the power conversion loss is increased because power is converted twice when a DC/DC converter having a maximum power point tracking function is combined with an inverter in order to realize maximum power point tracking and total efficiency of the power generating system is lowered. SOLUTION: Maximum power point tracking is realized without employing a DC/DC converter by keeping optimal operating conditions of an inverter from the waveform of pulse voltage and current generated from solar cells when the instantaneous output power from the inverter varies over time.

Maximum power operating inverter system

PROBLEM TO BE SOLVED: To realize a digital amplifier whose source signal is a digital signal and which is not influenced by source voltage variation without a large increase in cost, and to reduce the distortion rate of a digital amplifier which has an analog input by making high-order feedback correction. SOLUTION: An input digital signal is converted into a binary signal such as a PWM signal, the difference between the output of a switching amplifier and the converted binary signal is detected and integrated, and its value is sampled. A PWM signal driving the switching amplifier is generated on the basis of the sampled signal to provide a digital amplifier which has small influence of source voltage variation and small S/N at a low cost. COPYRIGHT: (C)2006,JPO&NCIPI

Amplifier and amplifier with volume function

PROBLEM TO BE SOLVED: To successfully reduce components of an audible area of re-quantization noise while keeping carrier frequency in pulse width modulation low in a full-digital amplifier. SOLUTION: The carrier frequency in PWM is reduced a half of a control cycle of the PWM by performing control of the PWM by every half period of a pulse period. Thus, power efficiency in a digital amplifier is enhanced and electromagnetic noise is reduced. In addition, when a complementary type PWM is used, resolution of the PWM is enhanced while leaving clock frequency as it is by giving difference in modulation degrees between tow PWM signals. COPYRIGHT: (C)2006,JPO&NCIPI

Digital pulse width modulation signal generator

PROBLEM TO BE SOLVED: To provide a low-distortion pulse width modulating signal generator, capable of preventing performance degradation by harmonic wave distortions caused by pulse width modulation in a full-digital amplifier and of reducing the phenomenon that the noise floor in audible area is lifted by the pulse width modulation. SOLUTION: By feeding signal distortion generated by the pulse width modulation back to a noise shaping filter, the harmonic wave distortion is reduced, and a feedforward signal for harmonic wave distortion compensation is superimposed on the input of a quantizer. The feedforward signal is generated by making the power function act statically on the input signal. COPYRIGHT: (C)2006,JPO&NCIPI

Low-distortion pulse width modulating signal generator

PROBLEM TO BE SOLVED: To give a command enabling shortest time control to a multi-shaft motion controller. SOLUTION: In PTP (point-to-point) control, a target value of speed at the time of passing through each point is designated also in addition to the coordinate of each point, whereby a trajectory of movement considering speed can be designated, whereas only the value of coordinate of each point is designated in the past. A preliminarily calculated trajectory which attains the shortest time movement is instructed to the motion controller, whereby the shortest time control is attained. Since the trajectory can be designated with a minimized point number, the calculation of the trajectory for attaining the shortest time can be facilitated. COPYRIGHT: (C)2008,JPO&INPIT

Akihiko Yonetani

Papers

Maximum power operating inverter system

Amplifier and amplifier with volume function

Digital pulse width modulation signal generator

Low-distortion pulse width modulating signal generator

Motion controller, motion planner, multi-shaft servo system and servo amplifier