JP3741434B2 - Electric motor operating device - Google Patents

Description

  The present invention relates to an electric motor operating device using a solar cell as a power source.

  In recent years, global warming, depletion of fossil fuels, nuclear accidents, radioactive contamination by radioactive waste, etc. have become problems, and interest in the global environment and energy is rapidly increasing. Under such circumstances, solar cells and the like are expected as inexhaustible and clean energy sources. There are various scales of systems for using solar cells, from several watts to thousands of kilowatts. There are also a wide variety of types, such as those that directly use electric power, those that store electricity in a battery, and those that are used in conjunction with a commercial power source. Among these, what is proposed as a solar pump system that draws water from water sources such as wells and rivers for irrigation and drinking, especially in areas with high solar radiation and non-electrified areas in the tropics. This is particularly effective because it can save time and labor for fuel transportation. In addition, there is an advantage that water can be secured even when power supply or water supply is stopped in the event of a disaster such as an earthquake.

FIG. 2 shows a configuration of a water supply apparatus using a solar pump system which is a conventional example and is an object of application of the present invention. In the figure, the DC power of the solar cell 1 which is an unstable battery power source is supplied to the pump 3 via the pump operation device 8. The water in the well 15 is pumped and stored in the water tank 9 by the pump 3 through the first liquid transport pipe 11. Water in the water supply tank 9 is supplied through the second liquid transfer pipe 16 and the valve 10.
JP 56-132125 A JP-A-57-153531 JP 60-49995 A

  However, in the water supply apparatus of FIG. 2, in the case of using the pump operation apparatus 8 that operates the pump 3 with only the power source of the solar battery 1 as shown in FIG. At this time, the pump is operating, but water does not reach the discharge port, so water cannot be pumped.

  In order to avoid wasting power at this time, methods using a plurality of pumps as shown in FIG. 12 have been proposed in Japanese Patent Laid-Open Nos. 56-132125 and 57-153531. However, pumps are generally more efficient with larger capacities, and if multiple pumps have the same maximum capacity, only a part of the pumps can be moved during low solar radiation to reduce wasted power. , Efficiency is low and cost is high if you look through weak sunlight and strong sunlight.

  In addition, as shown in FIG. 13, a method for operating a pump while storing electric power of a solar cell in a storage battery is proposed in Japanese Patent Application Laid-Open No. 60-74995. However, since the operating voltage of the solar cell is fixed to the storage battery voltage and the solar cell cannot be operated at the maximum output point, solar energy cannot be used efficiently.

  In view of such problems of the prior art, an object of the present invention is to provide a motor driving device that operates a motor using the power of a solar cell, while ensuring a good efficiency by reducing the number of motors to one. In addition, even when the generated power is low, such as when the solar cell is in low sunlight, the power is not wasted, and when a certain level of power is obtained, the solar cell is operated at the maximum output state for efficient energy consumption. Is to provide a highly reliable and highly efficient electric motor driving device with a simple configuration.

In order to solve the above problems, the present invention stores a solar cell, power conversion means for converting electric power from the solar cell and supplying it to an electric motor, and storing electric power connected in parallel to the solar cell. A timepiece for presetting a single power supply mode period in which the electric motor is operated only by the output of the solar cell, the solar cell, the power storage unit, and the power conversion unit. Opening / closing means interposed between a connection point and the power storage means, output value detecting means for detecting an output value of the solar cell, and opening and closing the opening / closing means during the single power supply mode period, the single power supply Outside the mode period, an open / close control means for controlling the open / close means based on a signal output by the output value detection means is provided.

  According to said structure, it can supply water without wasting solar energy at the time of weak solar radiation by providing an electrical storage means. In other words, FIG. 3 shows changes in the amount of power generated by a solar cell on a clear day, but conventionally, when a single pump is used to pump and supply water to a storage tank without electricity storage means, the generated power during weak solar radiation The parts a and b are wasted. On the other hand, in the case of the present invention, the generated power at the time of weak solar radiation is stored in the power storage means, so there is almost no wasted part. In addition, when the power storage means is sufficiently charged, the power stored in the power storage means is supplemented to operate, so the power storage means with a small capacity may be used. Efficient without loss of discharge. Further, when the operation can be performed only with the electric power of the solar cell, the power storage means is disconnected, and the operation can be performed with the maximum output point voltage of the solar cell as shown by C in FIG. Also, by using one pump, it is possible to transport liquid more efficiently and to reduce the cost of the apparatus than when using two small capacity pumps.

  That is, according to the present invention, in the solar pump system using solar cells, the following effects can be obtained by providing the power storage means and the opening / closing means and controlling the operation of the opening / closing means and the power conversion means.

(1) By storing and using electric power during low solar radiation, solar energy can be used efficiently, and the pump efficiency can be increased as compared with a method using a plurality of pumps.
(2) When the electricity is stored in the electricity storage means, the power during weak sunlight is supplied directly to the inverter, and the shortage is replenished from the electricity storage means. Compared to a system that stores generated power, the efficiency of power use is better.
(3) When operating only with the electric power of the solar cell, the power storage unit can be disconnected by the opening / closing unit, and the maximum output point tracking control of the solar cell can be performed, so that the utilization efficiency of the solar cell can be improved.
(4) The control device is simple.
(5) Since the required capacity of the storage means is relatively small, it can be realized at a low cost.
(6) If a nickel hydride battery or an electric double layer capacitor capable of deep discharge is used for the power storage means, the power storage means can be reduced in size, weight, and life.

  In a preferred embodiment of the present invention, the power conversion means is controlled for maximum power point tracking operation during the single power supply mode period, and is fixed until the opening / closing means is opened after the single power supply mode period. It has the electric power control means which carries out frequency operation control, It is characterized by the above-mentioned.

Further, the power control means stops the operation of the power conversion means when the voltage value detected by the output value detection means falls to a predetermined discharge inhibition voltage after the single power supply mode period. The electric motor driving device according to claim 2.
The non-stable power source is a solar cell, and the electric motor is an electric pump. In addition, the output value detection means includes an output voltage detection means and an output current detection means.

  FIG. 1 shows a basic configuration of a photovoltaic power generation system using a voltage control method according to an embodiment of the present invention. This solar power generation system is applied to, for example, the water supply system shown in FIG. In FIG. 1, the DC power of the solar cell 1 that is an unstable power source is converted into power by the power conversion means 2 and supplied to the load 3. The power conversion means 2, the output value detection means 4, the power storage means 5, the opening / closing means 6 and the control means 7 constitute an electric motor operating device 8 (see FIG. 2) which is a feature of the present invention. Reference numeral 20 denotes a backflow prevention means.

  Examples of the solar cell 1 include a solar cell using amorphous silicon such as amorphous silicon, single crystal silicon, polycrystalline silicon, or a compound semiconductor. Usually, an array or a string is configured so that a desired voltage and current can be obtained by combining a plurality of solar cells in series and parallel with direct current.

  Examples of the power conversion means 2 include a DC / DC converter using a switching element such as a power transistor, power MOSFET, IGBT, and GTO, and a self-excited voltage type DC / AC converter. These are determined depending on whether a DC pump or an AC pump is used as the load 3. The power conversion means 2 can control the input / output voltage, the output frequency, and the like by changing the on / off duty ratio of the gate pulse of the switching element.

  The pump 3 includes a direct-current pump and an alternating-current pump. The direct-current pump may be directly connected or connected via a DC / DC converter. However, the DC pump generally has a contact portion such as a commutator, and an AC pump without a contact portion is often used in consideration of the lifetime. Especially in the case of a large-scale system, an AC pump is preferably used. In addition, there are various types of pumps such as a centrifugal pump and an axial flow pump, which may be selected according to the application. When a direct-current pump is directly connected to the solar cell 1 as the pump 3, the power conversion means 2 is a simple opening / closing means and is configured in the same manner as the opening / closing means 6 described later.

  The output value detection unit 4 includes a voltage detection unit 41 and a current detection unit 42. The voltage detection means 41 divides the output voltage of the power source 1 with a resistor and sends the voltage value signal to the output setting means. At this time, it is desirable that the detection signal transmission circuit is isolated from the output circuit of the power supply 1 by a photocoupler or the like that can completely insulate the input and output in order to avoid noise and the like. When the output setting means 71 and the opening / closing control means 72 of the control means 7 are constituted by digital circuits, the voltage detection means 41 converts the voltage value signal into a digital value by A / D conversion and outputs the output setting means 71. And sent to the opening / closing control means 72.

  The current detection means 42 converts the current into a voltage using a Hall element or a standard resistor, and outputs the detection signal as an analog value or a digital value to the output setting means 71 and the switching control means 72 of the control means 7 in the same manner as the voltage detection means 41. Send it in.

  It is preferable that the A / D converter used when the detection means 41 and 42 are realized by a digital circuit is sufficiently fast and highly accurate. Specifically, the A / D converter has a resolution of 10 bits or more and a sampling of 50 KHz or more. Those with speed are preferred. By using such an A / D converter, a control system having an error of 0.1% or less and a response of 1 second or less can be configured.

The storage means 5 can be a lead storage battery, a nickel metal hydride battery, an electric double layer capacitor, or the like, and is preferably selected according to the scale of the system and the storage capacity. A comparatively small capacity capable of deep discharge may be used. In particular, nickel-metal hydride batteries are capable of 100% deep discharge, are small in size and have a long life, and electric double layer capacitors have a characteristic that their life is semi-permanent. It is desirable that the terminal voltage of this power storage means be set to approximately the maximum output point voltage of the power supply 1.

  The opening / closing means 6 can be opened and closed by an external signal such as a relay, a solid state relay, or a switching element such as a transistor, and any current capacity and withstand voltage can withstand the capacity and voltage of a solar cell or a load. Good.

The control unit 7 includes an output setting unit 71, an opening / closing control unit 72, and a power control unit 73.
The output setting means 71 performs an operation based on the detection signal supplied from the output detection means 4 to determine the output voltage setting value of the solar cell 1, and the output voltage of the solar cell 1 becomes this setting value. In this way, the flow rate of the power converter 2 is controlled. The output setting means 71 can be realized by an analog circuit, but it is easier to change parameters or the like if it is realized by a digital circuit and the calculation is made into software. In this case, it is embodied as a control microcomputer and can be constituted by a CPU, a RAM, a ROM, an input / output port, a numerical calculator, and the like.

  The opening / closing control means 72 performs a calculation based on the detection signal from the output detection means 4 and outputs a signal to the opening / closing means 6 and the power control means 73. The open / close control means 72 can be realized by an analog circuit such as an operational amplifier, but this function may be incorporated in the control microcomputer.

  The backflow prevention means 20 prevents a current from flowing back from the storage battery 5 to the solar battery 1. This includes rectifier diodes, Schottky barrier diodes, etc. In low voltage systems, Schottky barrier diodes should be used in consideration of losses due to forward voltage drop. .

  The power control means 73 is a so-called gate drive circuit, and generates a gate pulse by an instantaneous value current comparison, a sine wave / triangular wave comparison method, or the like. Thereby, the flow rate of the power converter 2 is controlled so as to coincide with the output of the output setting means 71 of the battery power source. The power control means 73 can be constituted by an analog circuit or a digital circuit. Many commercially available power conversion means incorporate some or all of such power control means, and most of them have recently been digitized and are equipped with a CPU and DSP. When the power conversion means to be used includes a part or all of the power control means, the power control means 71 of the control means 7 creates a signal necessary for operating the power conversion means. In that case, this function may be incorporated in the control microcomputer.

  When digitized, the power control means 73 has a configuration similar to that of the output setting means 71 and the opening / closing control means 72 described above, and these can also be used together.

Examples of the present invention will be described below.
[Example 1]
In the configuration of FIG. 1, ten amorphous solar cell modules (trade name UPM-880, manufactured by USSC) are used in series as the solar cell 1, and the power conversion means 2 is an IGBT that is a self-extinguishing switching element. A full-bridge three-phase inverter was configured using (Insulated Gate Bipolar Transistor). The IGBT is a high withstand voltage high speed switching element, and is preferably used for an inverter of several hundred W to several tens KW class. An AC three-phase motor direct-coupled magnet pump 3 was connected to this output.

  The liquid conveyance system by the pump was configured as shown in FIG. Water was stored in a FRP (reinforced plastic) water tank 17, and a liquid intake 18 was provided at a height of 0.1 m of the container 17. The liquid transport path 11 uses a vinyl hose with an inner diameter of 50 mm, the pump 3 is installed at a height of 0.1 m with respect to the bottom surface of the container 17, and the suction port 31 is connected to the water storage tank 17. The vinyl hose 11 was installed from the discharge port 32 to a height of 15 m. A flow meter 13 was attached in the middle of the vinyl hose 11, and the tip was inserted into a hard vinyl chloride pipe 12 having an inner diameter of 75 mm. In this way, the pumped water was lifted to 15 m by the pump 3 and returned to the water storage tank 17 using the pipe 12 as a drain.

  The voltage detection means 41 of the output value detection means 4 divides the output voltage of the solar cell array 1 by 20: 1 and digitizes it using an A / D converter (not shown) with 10V full scale 12-bit resolution. The control unit 7 is configured to send the data through the 8-bit parallel bus 43.

  As the current detection means 42, a standard resistor of 10 milliohms is inserted in series in the output circuit of the solar cell array 1, and the voltage at both ends is amplified 500 times by an operational amplifier (not shown), and then the same as the voltage detection means 71. After being converted into a 12-bit digital value using an A / D converter (not shown), the data is sent to the control means 7 via an 8-bit parallel bus 44.

  As the control means 7, a one-board microcomputer (Intel 8086) was used. The board is equipped with a general-purpose parallel input / output board, a memory, a numerical arithmetic coprocessor, a serial interface, and the like, and has a configuration suitable for this embodiment.

  The output setting of the power conversion means 2 by the control means 7 is the maximum output point tracking (MPPT) control of the solar cell using the power control method as disclosed in JP-A-6-348352 by the CPU of the one-board microcomputer. The output frequency of the power conversion means 2 was controlled to be performed.

  In addition, the open / close control by the control means 7 calculates the power value based on the voltage value input from the voltage detection means 41 and the current value input from the current detection means 42 by the CPU, and the power value and the voltage value are calculated. Based on the above, the opening / closing means 6 is determined to open / close. In conjunction with this determination, in order to start, stop and reset the pump 3, start / stop and reset signals are sent from the parallel output port to the control circuit of the inverter 2.

  For power control of the power conversion means 2, a known triangular wave comparison type PWM (pulse width modulation) was used. The carrier frequency was 2 KHz. This power control compares the sine wave of the frequency determined by the output setting command from the control means 7 with the output current value of the power conversion means 2 and changes the duty of the gate pulse (on time / (on time + off time)). Let

  Moreover, 13 12V lead acid batteries were connected in series as a power storage means.

Next, the system control method of the present embodiment will be described with reference to the flowchart of FIG.
A solar cell output single operation mode period in which the pump can be operated only by the output of the solar cell is determined in advance. It is determined by a clock inside the personal computer whether or not the current time is the solar cell output single operation mode period. If the time is not within this period, the opening / closing means 6 is closed and the storage battery 5 is connected. Thereby, the output voltage Vpv of the solar cell 1 is fixed to the voltage of the storage battery 5 or a voltage lower than that. In this state, when the output voltage Vpv is smaller than a predetermined discharge permission voltage (charge prohibition voltage), the inverter 2 is stopped and the storage battery 5 is charged (state 1). At this time, if the voltage Vpv exceeds the discharge permission voltage, the inverter 2 is operated at a constant frequency, and the pump 3 performs work by the power of the solar battery 1 and the power of the storage battery 5 (state 2).

  Further, during the inverter operation, when the voltage Vpv falls below the storage start voltage (discharge prohibition voltage), the inverter is stopped and charging is started (state 3). These states 1, 2, and 3 are repeated when it is not the solar cell output single mode period.

  When the time of the internal clock becomes a predetermined solar cell output single operation mode period, the opening / closing means 6 is opened and the inverter 2 is driven only by the electric power of the solar cell 1. Then, maximum output point tracking control is performed by changing the frequency.

  In this example, as described above, the maximum output point tracking control of the solar cell was performed using a power control method as disclosed in JP-A-6-348352. Thereby, electric power can be efficiently obtained from the solar cell. Various methods of this maximum output point tracking control have been proposed, and other methods can be used.

  As a result of operating the pump in this way, the operation time of the solar cell is 6 hours and 40 minutes in the Q portion of FIG. 7, and the operation time is 43 minutes longer than 5 hours and 57 minutes of the P portion when there is no storage battery. It was.

[Example 2]
In this example, 20 solar cells 1 were connected in series with 20 amorphous silicon solar cell modules (trade name MBC-131 manufactured by USSC). This was connected to an AC three-phase motor direct-coupled magnet pump (trade name PMD-613B2M, manufactured by Three Phase Electric) via a general-purpose inverter (trade name FREQOL-U100, manufactured by Mitsubishi Electric Corporation) as a power conversion means and its control device. Originally, the input of this general-purpose inverter is an alternating current input. However, since the alternating current is rectified and converted into a direct current inside, it can be operated with a direct current such as a solar cell.

  The liquid conveyance by the pump is as shown in FIG. Water was stored in a water intake container 17 of FRP (reinforced plastic) so that the water surface was about 0.5 m high, and a liquid intake 18 was provided at a height of 0.1 m of the container 17. The liquid transport path uses a vinyl hose 11 with an inner diameter of 25 mm, the pump 3 is installed at a height of 0.1 m from the bottom of the container 17, and its inlet 31 is connected to the water intake container 17. The vinyl hose 11 was installed from the discharge port 32 to a height of 2 m. A flow meter 13 was attached in the middle of the vinyl hose 11, and the tip was inserted into a hard vinyl chloride pipe 12 having an inner diameter of 50 mm. In this way, the water pumped up by the pump 3 was lifted up to 2 m, and returned to the water intake container 17 using the pipe 12 as a drain.

  The control means 7 is a personal computer (trade name PC-9801DA, manufactured by NEC), and the voltage detection means 41 resistance-divides the output voltage of the solar cell module 1 by 100: 1 to be used as an expansion slot of the personal computer. A voltage signal is sent to the A / D conversion port of the A / D / D / A conversion / parallel input / output board (product name: AB98-57B, manufactured by Adtech System Science) with 5V full scale 12-bit resolution. As the current detection means 42, a standard resistor of 10 milliohms is inserted in series with the solar cell array 1, and the voltage at both ends is amplified 500 times with an operational amplifier, and then the A / D converter similar to the voltage detection means 41 is used. After being converted into a 12-bit digital value, the data is sent to the control means 7 via an 8-bit parallel bus.

The personal computer is used as the output setting means 71, and the result calculated by the CPU is output as a frequency setting signal from the D / A conversion terminal of the A / D / D / A conversion / parallel input / output board. A signal was sent to the control circuit of the general-purpose inverter 2. In order to start, stop, and reset the pump 3, start / stop and reset signals were sent from the parallel output terminal of the input / output board to the control circuit of the general-purpose inverter 2.

  The open / close control means 72 also uses this personal computer, calculates the power value from the voltage value and current value by the CPU, and determines the open / close based on the power value and voltage value. In conjunction with this determination, in order to start, stop, and reset the pump, start / stop and reset signals were sent from the parallel output terminal of this board to the control circuit of the general-purpose inverter.

  Furthermore, 22 12V nickel-metal hydride batteries (capacity 0.2 Ah) were connected in series as power storage means.

The system control method of this embodiment is as shown in FIG.
That is, when the generated electric power of the solar cell 1 is insufficient and the pump 3 cannot pump up water and the storage battery 5 is not sufficiently charged, that is, the generated electric power is a predetermined solar cell output single operation mode. When the voltage is lower than the power value and the voltage Vpv is lower than the predetermined discharge permission voltage, the inverter 2 is stopped, the opening / closing means 6 is closed, and the power storage means 6 is charged (state 1). At this time, if the voltage exceeds a predetermined discharge permission voltage (charge prohibition voltage) Vpv, the inverter 2 is operated, and the pump 3 performs work by the power of the solar battery 1 and the power of the storage battery 5 (state 2).

  Further, during the inverter operation, when the voltage Vpv falls below the storage start voltage (discharge prohibition voltage), the inverter is stopped and charging is started (state 3). Thus, these states 1, 2, and 3 are repeated when it is below the solar cell output single operation mode power value.

  When the generated power of the solar cell 1 becomes equal to or higher than a predetermined solar cell output single operation mode power value, the opening / closing means 6 is opened and the inverter 2 is driven only by the power of the solar cell 1. Then, maximum output point tracking control is performed by changing the frequency.

  As a result of operation with such a configuration, when compared on a sunny day with an insolation of about 6.0 kWh (day · m3), the integrated flow rate is about 14.5 m3 as shown in FIG. Compared with 1 m3 and about 13.1 m3 when there is no switch, this example was higher and more efficient operation was possible.

  In this example, as a result of assembling the system using a nickel metal hydride battery, the weight of the power storage means was about 0.7 kg. When a lead storage battery is used in this system to obtain the same power storage performance, the weight is about 2.1 kg, and the weight can be reduced.

  In addition, even on a cloudy day or rainy day, the pump can be operated when the storage battery is fully charged and the battery is fully charged.

[Example 3]
In this example, 20 amorphous silicon solar cell modules (trade name MBC-131 manufactured by USSC) were connected in series as the solar cell 1 in FIG. This was connected to the direct current pump 3 through a DC / DC converter as the power conversion means 2 and its control device.

  The liquid conveyance path by the pump is the same as in the first embodiment.

  The DC / DC converter 2 can change a DC voltage by an external signal.

  The voltage detection means 41 is configured to divide the output voltage of the solar cell array by 20: 1 and send it to the output setting means 71 and the open / close control means 72 via an 8-bit parallel bus.

  As the current detection means 42, a standard resistor of 10 milliohms is inserted in series in the solar cell array circuit, and the voltage at both ends thereof is amplified 500 times by an operational amplifier and then sent to the setting means 71.

As the output setting means 71 and the opening / closing control means 72, a one-board microcomputer in which M37710 manufactured by Mitsubishi Electric was mounted on the CPU was used. The board is equipped with a general-purpose parallel input / output board, a memory, a serial interface, an A / D converter, and the like, and has a configuration suitable for this embodiment. The result calculated by the CPU sent a signal to the control circuit of the DC / DC converter 2 as an output voltage set value. In addition, in order to start, stop and reset the pump, a start / stop signal was sent to the control circuit of the DC / DC converter 2 from the parallel output terminal of this board.
The control method of this embodiment is the same as that of the second embodiment.

  As a result of operating with such a configuration, the operating voltage of the solar cell becomes as shown in FIG. 10, and it is necessary to always operate with the terminal voltage of the storage battery 5, compared to the conventional system in which the storage battery 5 is connected without the opening / closing means 6. The utilization efficiency of the solar cell 1 was good.

  According to the above-described embodiment, in the solar pump system using the solar cell, by providing the power storage means and the opening / closing means and controlling the operation of the opening / closing means and the power conversion means, the following effects can be obtained.

(1) By storing and using electric power during low solar radiation, solar energy can be used efficiently, and the pump efficiency can be increased as compared with a method using a plurality of pumps.
(2) When the electricity is stored in the electricity storage means, the power during weak sunlight is supplied directly to the inverter, and the shortage is replenished from the electricity storage means. Compared to a system that stores generated power, the efficiency of power use is better.
(3) When operating only with the electric power of the solar cell, the power storage unit can be disconnected by the opening / closing unit, and the maximum output point tracking control of the solar cell can be performed, so that the utilization efficiency of the solar cell can be improved.
(4) The control device is simple.
(5) Since the required capacity of the storage means is relatively small, it can be realized at a low cost.
(6) If a nickel hydride battery or an electric double layer capacitor capable of deep discharge is used for the power storage means, the power storage means can be reduced in size, weight, and life.

The basic composition of the pump operation device concerning one embodiment of the present invention is shown. The structure of the solar cell water supply system which is an example of the application object of this invention is shown. It is a graph showing the daily power generation amount. It is a graph showing the change of the output voltage of the solar cell on the 1st. 1 shows a configuration of a pump system according to an embodiment of the present invention. It is a flowchart which shows operation | movement of the pump operation apparatus in the system of FIG. It is a graph showing the electric power supplied to the pump in the system of FIG. It is a flowchart which shows operation | movement of the pump operation apparatus which concerns on the 2nd and 3rd Example of this invention. It is a graph showing the integrated flow volume when it is made to operate | move with the structure of Example 2 of this invention. It is a graph showing the output voltage of the solar cell when it is made to operate | move with the structure of Example 3 of this invention. 1 shows a first example of a conventional pump system. 2 shows a second example of a conventional pump system. 3 shows a third example of a conventional pump system.

Explanation of symbols

  1: solar cell (unstable power supply), 2: power conversion means, 3: pump, 4: output value detection means, 41: voltage detection means, 42: current detection means, 5: power storage means, 6: switching means, 7 : Control means, 71: output setting means, 72: open / close control means, 73: power control means, 8: pump operating device, 9: water tank, 10: valve, 11: liquid transport pipe, 12: drain pipe, 13: Flow meter, 16: liquid transport pipe, 17: water storage tank, 20: backflow prevention means, a, b: conventionally wasted power, A: charging period, B: discharge period, C: solar cell output single operation, P: Operation possible period in the present invention, Q: Conventional operation possible period.

Claims (3)

In an electric motor driving device comprising a solar cell, power conversion means for converting electric power from the solar battery and supplying the electric power to an electric motor, and electric storage means for storing electric power connected in parallel with the solar cell,
A timepiece for presetting a single power supply mode period for operating the electric motor only by the output of the solar cell;
An opening / closing means interposed between a connection point between the solar cell, the power storage means, and the power conversion means, and the power storage means;
Output value detecting means for detecting the output value of the solar cell;
Opening / closing means is opened during the single power supply mode period, and open / close control means for controlling the open / close means based on a signal output by the output value detection means outside the single power supply mode period. Electric motor driving device.   The power conversion means has power control means for performing maximum power point tracking operation control during the single power supply mode period and performing constant frequency operation control after the single power supply mode period until the opening / closing means is opened. The motor driving device according to claim 1, wherein:   The power control means stops the operation of the power conversion means when the voltage value detected by the output value detection means falls to a predetermined discharge inhibition voltage after the single power supply mode period. Item 3. The electric motor operating device according to Item 2.

Images