JPS58112422A - Pump controller with solar battery as power source - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pump control device using a solar cell as a power source. A conventional pump device that uses a solar cell as a power source and drives a pump with a DC motor has a fundamental problem in that the characteristics of the pump/DC motor are incompatible with the characteristics of the solar cell system.

Therefore, in the present invention, a pulse modulation type converter is used to bring the operating point of the solar cell system closer to its optimum operating point.

To explain the diagrams, Fig. 1 shows the ■-working characteristics of a pump/DC motor system with electric current on the vertical axis and voltage ■ on the horizontal axis, where 1 shows the characteristic curve and dotted line 2 shows the starting characteristics. Similarly, 3 indicates the case of stop. Once the characteristics of the piping system in which the pump is used are determined, the characteristic curve 1 is determined.

FIG. 2 shows the characteristics of a solar cell system using the solar radiation intensity Be as a parameter, with the vertical axis representing the current and the horizontal axis representing the voltage V. (It is the same as in Figures 3 and below, where the vertical axis is the electric current and the horizontal axis is the voltage V.) The solar radiation intensity is
Eel > Ke2 > Ee3, that is, curve 4
．． The solar radiation intensity is highest in order of 5.6.

Curves 4', 5', and 6' are curve 4 of solar radiation intensity, respectively.
．． 5.6 shows the output of the solar cell corresponding to the trajectory V of the optimal operating point. p is as shown by curve 7. Figure 3 shows the ■-■ characteristic curve 1 of the pump/DC motor system and the characteristics of the solar cell system in the same graph.As is clear from the figure, as the solar radiation weakens, curves 1 and 7 However, the solar cells were not fully utilized in terms of their characteristics under low solar radiation. FIG. 4 shows the change in characteristic curve 1 when the pulp opening degree is changed, and the more the pulp opening degree becomes 1' or 1', the smaller the pulp opening degree is. As the operating characteristics of the pump system constantly change in this way, it is time to adjust the characteristics of the solar cell system, the characteristics of the pump/DC motor system, and the characteristics of the solar cell system depending on solar radiation fluctuations and changes in pulp opening. It was difficult to match the two.

Figure 5 shows a block diagram of the control device d according to the present invention, and Figure 6 shows a conventional device.

In the figure, 20F'i, solar cell 21 is a backflow prevention diode, 22 is a chopper, 23 is a capacitor that stores the energy of the solar cell when chopper 23 is open, and 24, 25, and 26 are smoothing capacitors, respectively. Shows circuit glue, diodes, and capacitors. 27 is a DC motor, and 28 is a pump. 30it oscillation circuit, 31
3 is a pulse width modulation circuit, 32 is a reference voltage (vo) generation circuit, and 33 is a voltage comparison circuit.

FIG. 7 shows the operating points of the =gth machine and solar cell system in the case of this invention in terms of V-workability.

In FIG. 5, with respect to the voltage v2 flowing through the DC motor 27, the current line 2ti, and the primary side line 11 Vl of the chopper 22, ignoring the power loss of the chopper and assuming that the duty cycle of the chopper is α, V, = α ■ 1 % engineering 2 - engineering 1
/α. In FIG. 7, since Vl is constant,
Changes on hyperbola 8. Therefore, v2 is the operating point of the electric motor, and ■IVI is the operating point of the solar cell. That is, the primary side of S v! Work 1 becomes work 2 on the secondary side by the chopper 22. In this way, as shown in Fig. 7, in the conventional device, the solar radiation required for the operation of 2 ms (curve 4 in the figure) is ms (curve 4 in the figure). 2v2 operation becomes possible due to solar radiation (curve 5 in the figure). That is, in this invention, the secondary voltage v2 is detected and compared with the reference voltage vO generated in the circuit 32 in the circuit 35. Then, the calculation vo-■2 is performed, and the duty cycle of the chopper S is brought closer to 1 as ■2 is larger (that is, the solar radiation intensity is larger).

In FIG. 8, the chopper S is operated at a duty cycle that corresponds to characteristic 1 of the electric motor and the operating point of the solar cell. As mentioned above
Since v2=αvl, as shown in Fig. 7, <vl and ■2
The difference (VtVz) becomes 'V+ (1a). In Figure 8, point v and II are 10. , v2r, point is 102, and as the solar radiation gradually weakens, v11kl' point is 10<, V, '■
2' point is 102', v, #work 1' point is 1 o1#,
v2 #work2' point is 102', ■ the duty cycle at the time of 2 is α, ■ at the time of 2', αl, V211
When α'..., then α〉α'〉α', so (1-α)〈(1-α')＜(1-α'), and between 10 and 102 Opening, 101' and 102
', and the difference between 101' and 102' gradually increases, curve 9 can be given a slope close to optimal operation curve 7 shown in FIG. 7, and the solar cell can operate optimally even under low solar radiation. It can be operated at a point close to the point.

FIG. 9 is an explanatory diagram of a chopper control circuit, and FIG.
Figure (A) Triangular wave from Fi oscillation circuit 30 and VO-Vl
, VO-V2', Vo-Vz', (b)
t- is the square wave that drives the chopper during low solar radiation, (C) is the square wave that drives the chopper during high solar radiation, the time of the t2Vi- cycle, the time when the tl l"j wave is output, and the duty The cycle α is α=−, αrv.−Vl.

2 In this way, the present invention uses a pulse modulation type converter to obtain a control device that can bring the operating point of a solar cell close to its optimum operating point even during low solar radiation.

[Brief explanation of the drawing]

Figure 1 shows the V-X characteristic curve of a DC motor, Figure 2 shows the V-characteristic curve of a solar cell, and Figure 3 shows the V-workability curve of a DC motor and the characteristics of a solar cell. 4 is a diagram showing a change in the V-workability curve of a DC motor depending on the pulp opening, FIG. 5 is a block diagram of the device of the present invention, and FIG. 6 is a diagram showing a conventional device. Figures 7 and 8 are diagrams showing the relationship between the operating points of the motor and the solar cell, Figure 9 (a) shows the triangular wave from the oscillation circuit, and Figure 9 (b) shows the relationship between the operating points of the motor and the solar cell. FIG. 9 (Q) is a diagram showing a square wave at a time of high solar radiation. Explanation of symbols 1...V-1 characteristic curve of DC motor 4.5.6...V-1 characteristic curve of solar cell 7...Locus of optimum operating point 8...■The mechanical strength is constant Hyperbola 9...-Next input V-4 characteristic curve 20...Solar cell 22, . . ., Chopper 27...DC motor 28...Pump 30...Emission circuit 31...Pulse width Modulation circuit 32...Reference voltage generation circuit 36...Voltage comparison circuit (3 others) (7) ■ Fig. 2

Claims (1)

[Claims] In a pump device driven by a DC motor using a solar cell as a power source, a pulse width modulation type DC-DC converter is installed, and the greater the amount of solar radiation, the smaller the conversion rate, and the smaller the amount of solar radiation, the larger the sum conversion rate. A control device for a pump using a solar cell as a power source, characterized by controlling the operating point of the solar cell to approach its optimum operating point.