Method and device for controlling photovoltaic inverter, and feed water device
First Claim
1. A method of controlling a photovoltaic inverter for variable-speed controlling a motor with solar cells as its power source comprisinga step of starting up the motor by supplying a start-up power through the photovoltaic inverter from said solar cells while monitoring the output power and voltage of said solar cells,a step of storing the voltage value of the solar cells as a reference voltage (VBASE) when the power of said solar cells reached the maximum power point in the process of accelerating the rotational speed of this motor for a given acceleration time,a step of continuing accelerating until the voltage of the solar cells shifts from said reference voltage (VBASE) to a first voltage (VBASE−
- VOVER) that is lower than said reference voltage by a previously set voltage (VOVER),a step of, after the voltage of the solar cells reached the first voltage (VBASE−
VOVER), decelerating the speed of said motor for a given deceleration time until the voltage of the solar cells shifts from this voltage to said reference voltage (VBASE), anda step of, after this deceleration operation is over, when the voltage of the solar cells is within the given allowable voltage regulation range (Hb) with reference to said reference voltage (VBASE), controlling said photovoltaic inverter in such way that said motor may continue operating at the current speed.
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Accused Products
Abstract
A photovoltaic inverter control method includes steps of monitoring a variation in output voltage of a solar battery by a power and voltage monitoring circuit (51) and, when the variation occurs, accelerating or decelerating an electric motor (3) to maximize the output voltage of the solar battery (1), whereby the electric motor for driving, for example, a pump and a fan by the solar battery as a power source can be driven by a photovoltaic inverter always at the maximum power point of the solar battery.
282 Citations
11 Claims
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1. A method of controlling a photovoltaic inverter for variable-speed controlling a motor with solar cells as its power source comprising
a step of starting up the motor by supplying a start-up power through the photovoltaic inverter from said solar cells while monitoring the output power and voltage of said solar cells, a step of storing the voltage value of the solar cells as a reference voltage (VBASE) when the power of said solar cells reached the maximum power point in the process of accelerating the rotational speed of this motor for a given acceleration time, a step of continuing accelerating until the voltage of the solar cells shifts from said reference voltage (VBASE) to a first voltage (VBASE− - VOVER) that is lower than said reference voltage by a previously set voltage (VOVER),
a step of, after the voltage of the solar cells reached the first voltage (VBASE−
VOVER), decelerating the speed of said motor for a given deceleration time until the voltage of the solar cells shifts from this voltage to said reference voltage (VBASE), anda step of, after this deceleration operation is over, when the voltage of the solar cells is within the given allowable voltage regulation range (Hb) with reference to said reference voltage (VBASE), controlling said photovoltaic inverter in such way that said motor may continue operating at the current speed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
- VOVER) that is lower than said reference voltage by a previously set voltage (VOVER),
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10. A controlling device of a photovoltaic inverter for variable-speed controlling a motor fed with power from solar cells comprising power and voltage monitoring means for monitoring respectively the power and voltage of said solar cells, an instructing value operation means for outputting acceleration or deceleration instructions based on this power and voltage monitoring means, a gradient coefficient operation means for outputting acceleration time or deceleration time, an adjustable speed controlling means for outputting frequency instructions based on the outputs of the instructing value operation means and the gradient coefficient operation means, wherein the voltage value of said solar cells prevailing at a time when the power of said solar cells reached the maximum point in the process of accelerating said motor is stored as a reference value (VBASE), at the same time the motor is accelerated until the voltage of said solar cells shifts from said reference voltage (VBASE) to first voltage (VBASE−
- VOVER) that is lower than the reference voltage by a previously set voltage (VOVER), and after the voltage of said solar cells reached said first voltage (VBASE−
VOVER) the motor is decelerated until the voltage of said solar cells reaches said reference voltage (VBASE), and after this deceleration operation, when the voltage of said solar cells is within the given allowable voltage regulation range (Hb) with reference to said reference voltage (VBASE), the photovoltaic inverter is controlled in such a way that said motor may continue operating at the present rotational speed.
- VOVER) that is lower than the reference voltage by a previously set voltage (VOVER), and after the voltage of said solar cells reached said first voltage (VBASE−
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11. A water feeding device for feeding water by driving a pump variable-speed controlled by a photovoltaic inverter fed with power from solar cells wherein, in the process of starting up said motor and accelerating said motor by a given acceleration time while monitoring respectively the power and voltage of said motor, the voltage value of said solar cells prevailing at a time when the power of said solar cells has reached the maximum power point is stored as a reference voltage (VBASE), and the motor is accelerated until the voltage (Vo) of said solar cells shifts from said reference voltage (VBASE) to a first voltage (VBASE−
- VOVER) that is lower than the reference voltage by a previously set voltage (VOVER), and after the voltage of said solar cells has reached said first voltage (VBASE−
VOVER), the motor is decelerated until the voltage of said solar cells shifts from this voltage to said reference voltage (VBASE), and after this deceleration operation is over, when the voltage of said solar cells is within the given allowable voltage regulation range (Hb) with reference to said reference voltage (VBASE), said motor is kept operating at the present rotational speed to drive the pump and to feed water.
- VOVER) that is lower than the reference voltage by a previously set voltage (VOVER), and after the voltage of said solar cells has reached said first voltage (VBASE−
Specification