摘要:
An electric power conversion unit 2 for driving a pump 3 run by electric power generated by a solar panel 1, a storage battery 5 connected to the solar panel 1 via the switch 6, and a controller 7 for controlling the electric power conversion unit 2 and the switch 6 are provided. The controller 7 closes the switch 6 during any period when the amount of insolation is large and performs the maximum power point tracking control of the solar panel 1, and otherwise, controls the electric power conversion unit 2 to drive at one of plural fixed frequencies in dependence upon an output voltage from the solar panel 1 by closing the switch 6. Accordingly, it is possible to utilize output from an unstable electric power supply efficiently, such as a solar cell, thereby providing a reliable electric motor driving apparatus having a simple configuration and a control method therefor.
摘要:
A conveying system comprising a pump whose power source is an unstable electric power supply, such as a solar cell; a first supply pipe for conveying liquid from an intake to the pump; a second supply pipe for conveying the liquid from the pump to a discharge opening; a liquid storage tank provided at a position which is below the discharge opening and above the pump; a third supply pipe branching from the second supply pipe, for conveying the liquid to the liquid storage tank; a fourth supply pipe connected between the liquid storage tank and the first supply pipe; a first valve, provided between the branching point of the first and fourth supply pipes and the intake, for opening and closing the first supply pipe; a second valve, provided between the branching point of the second and third supply pipes and the discharge opening, for opening and closing the second supply pipe; a third valve for opening and closing the third supply pipe; and a fourth valve for opening and closing the fourth supply pipe. The conveying system is capable of conveying liquid, fine powder, and so on, at high efficiency with a single pump even when available electric power supplied from the unstable electric power supply is low by performing open/close control of the second and fourth valves.
摘要:
In order to prevent a device serving as a load from being destroyed or causing an operation error while assuring an optimum operation voltage of a solar cell, and to stably, efficiently obtain power, a DC source system, in which a solar cell (1) and a DC source (3) are connected to an output terminal connected to a load (2) in parallel with each other, includes a first switch (5) arranged between the load (2) and the solar cell (1), a second switch 7 arranged between the load (2) and the DC source, and a capacitor (6) arranged between the load and the first switch in parallel with the solar cell.
摘要:
A voltage control apparatus which is robust against disturbances such as variations in solar radiation amount around a solar cell, and has quick response, has a voltage detection unit (4) for detecting the voltage value of a battery power supply (1), a power conversion unit (2) for performing predetermined conversion of electric power supplied from the battery power supply, and supplying the converted electric power to a load or a commercial AC system (3), an output setting unit (5) for setting the output value of the power conversion unit on the basis of the voltage detection value, and a control unit (6) for controlling the power conversion unit on the basis of the output setting value. The output setting unit is constituted by a target voltage setting unit (51) for setting the target voltage value of the battery power supply, and an output calculation unit (52) for calculating the output setting value on the basis of the deviation between the voltage detection value and the target voltage value.
摘要:
In order to extract maximum power from a solar cell, maximum power point tracking (MPPT) control is performed under ordinary circumstances. If the output current of the solar cell becomes too small, the operating point of the solar cell is caused to fluctuate over a range wider than that of MPPT control at a period longer than that of MPPT control and the output voltage and current of the solar cell is sampled. In a case where it is indicated by power values obtained from the sample voltage values and current values that a plurality of maximal points of power value exist, a voltage value corresponding to a power value indicative of the largest value is set as the operating point of the solar cell.
摘要:
Power supplied from a battery power supply to a load through a power conversion unit is maximized with a relatively simple arrangement and a small processing load. In addition, an output command value for controlling the power conversion unit is detected, a set voltage for which the output command value is maximized is calculated with reference to a past or present set voltage, as needed, and set as the next set voltage such that the maximum output is supplied to the load without any erroneous operation in the case of variation in solar radiation. In this case, a plurality of voltages are sequentially set for a relatively short period. Output command values for the respective set voltages are fetched while setting the same voltage at the start and end of the operation. A variation in output command value caused by the fetching difference for the same set voltage is detected. The output command value for calculating the next set voltage is corrected in accordance with this variation.
摘要:
In a power generation system of this invention, the outputs from power generation layers electrically connected in series are input to corresponding power conversion devices, and boosted outputs are connected in parallel and fed to a load. Alternatively, the output from one of power generation layers electrically connected in series is input to a first power conversion device, and the serial output and the boosted output from the first power conversion device are connected in parallel, input to a second power conversion device, boosted, and fed to the load. Since the two power generation layers can be individually output-controlled, each power generation layer can be optimized basically without considering current balance. Since the optical spectrum utilization efficiency increases, the power generation efficiency increases. In addition, since the power can be fed not to separate loads but to one load, the convenience largely increases.
摘要:
To provide a cheap inverter which uses a single digital microprocessor and can execute a current control and a maximum power control without changing a design of a hardware even for any switching device or solar cell, there is provided a control apparatus of an inverter for converting a DC electric power into an AC electric power by using a switching device, wherein the control apparatus is constructed by an inversion discrimination circuit for receiving an output current or an output voltage and a reference signal and for discriminating whether a switching state of the switching device should be inverted or not and a gate pulse signal forming unit for changing the switching state of the switching device in response to an inversion request signal which is outputted from the inversion discrimination circuit. The gate pulse signal forming unit has a CPU for forming a gate pulse signal by an interrupting process by using the inversion request signal as an interruption control signal.
摘要:
In a charging control method and apparatus which can improve the operating efficiency of a power generation system and prolong the service life of an accumulation unit, a short-circuit switch is closed, and a current generated in a solar cell is charged in the accumulation unit in a charging state. With this charging, the terminal voltage of the accumulation unit rises. This voltage is detected by a detection unit and is loaded into a control unit. When the detected voltage rises to a predetermined voltage, the short-circuit switch is closed by a short-circuit control signal. The output current from the solar cell is then discharged to the ground, and charging is stopped. In this state, the control unit determines the connected state of a load from an output signal from the detection unit. When the closed state of the short-circuit switch is determined from an output signal from a detection unit, the control unit switches the short-circuit switch to an open state even if the voltage of the accumulation unit has not reached a charging start voltage. With this switching operation, discharging of an output current from the solar cell to the ground is stopped, and the output current from the solar cell is output to the accumulation unit and the load.
摘要:
In order to accurately and stably measure the output characteristics of a battery power supply device, especially, a large-scale solar cell module by an equipment that requires only a size and cost equivalent to those of an apparatus used for measuring a small-scale module, the light-receiving surface of the solar cell module is divided into areas each including a bypass diode, the output characteristics upon light illumination in units of divided areas are measured, the measured characteristics are synthesized, and the influence of bypass diode characteristics is subtracted from the synthesized characteristics, thereby calculating the output characteristics of the solar cell module.