Shown in Figure 2, consisting of Q1, D2, D1 in the figure a protection circuit, wherein D1 (1N4743) to the Zener diode (+13.5 V), D1 and D2 together form a bias circuit of the transistor Q1. R1 is a current limiting resistor of the Q1 tube. Circuitry external charger, such as the maximum threshold voltage of the battery is about 14.4 V, in the initial stage of charging batteries according to conventional undervoltage condition slowly rising start conducting when the battery voltage reaches the breakdown voltage of the Zener diode D1, D1 tube through Q1 tube conduction, prompting A decline in B terminal voltage, set the appropriate parameters to the highest value no greater than 14.4 V battery voltage across. The protection circuit causes the battery when the battery has been filled in the trickle charge state, which makes the battery charging protection function.

When the voltage across both ends of the battery voltage is higher than the solar panels, the battery may produce the phenomenon of reverse charging to solar panels. Once this happens, the solar panel is likely to be burned, causing losses. Thus, the overcharge protection circuit should also include the anti-charge circuit, i.e. by connecting a diode between the solar panels and the battery to prevent reverse charging of the batteries on the solar panel shown in Figure 3.

A solar street lights intelligent control system design

1.2 over-discharge protection circuit

Q2 from the comparator hysteresis comparator circuit has two threshold the voltage: VTHR and VTHL (VTHH> VTHL), a hysteresis area. , The comparator output is high when the battery voltage from the low elevated to VTHH;, the comparator output is low when the battery voltage decreases to VTHL. This time the battery terminal voltage will rise rapidly over the VTHL reach VTHH comparator still output low until after the battery is charging voltage increases to VTHH to output high again. Thus avoiding the oscillation of the circuit, to protect the load and battery.

Comparator positive terminal reflects the sampling of the battery voltage U3, comparator reflected in the negative terminal of the battery is the reference voltage U2. When U3> U2, the comparator output is high, Q1 turns on, Q1 of C is extremely low, Q3 is turned off, the load does not work; When U3

1.3 backup power

Solar panels in the rainy days can not charge the battery to work state, it is necessary to use the backup power supply to the circuit supply backup power using the AC to DC conversion, to convert alternating current to the rated DC voltage value to ensure that the circuit work properly.

1.4 Infrared light control control circuit

The system uses a BISS0001 chip, it is a high performance sensor signal processing integrated circuit, it is accompanied by a pyroelectric infrared sensor and a small amount of external components constitute passive pyroelectric infrared switch with independent high input The impedance of the op amp. The part of hardware implementation of integrated chip BISS0001, Transistor 8050, photoresistor, and infrared sensors can be selected to design. Infrared sensors, the sensors send infrared signal processing feedback to control the end, after the internal linear amplification, two-way the parcels,grid tie inverter signal processing, delay timing, timing, etc. blockade processing. Its feet 2 output high so the transistor 8050 is turned on, driving the relay pull-K, and then controlled by the relay contacts controlled object. Here triac relays can be replaced.

A solar street lights intelligent control system design

Operational amplifier OP1 pyroelectric infrared sensor output signal for the first-stage amplifier, and then the second stage amplifier coupled to the amplifier OP2 by C3 processing via a bidirectional amplitude discriminator voltage comparator COP1 and COP2 detection valid trigger signal the Vs to go start delay timer output signal Vo by transistor T1 zoom drive relays to switch on the load. Wherein, R3 is a photosensitive resistor, is used to detect the environmental illuminance. As lighting control, if the environment is brighter, the resistor values ​​for R3 will be reduced, so the 9-pin input is held low, thereby blocking the trigger signal Vs. SW1 is the operating mode selector switch. When SW1 and 1 end connectivity, the chip in a reusable trigger work; SW1 and 2 end connectivity, the chip is not repeated trigger work. Diagram, R6 can adjust the size of the amplifier gain, artwork selected 10 K, and actual use can be used 3 K, can increase the gain of the circuit to improve the circuit performance. Output delay time Tx, triggered by external R9 and C7 resize blockade time Ti by external R10 and C6 resize, R9/R10 with 470 Ω C6/C7 can choose 0.1 V.

2 innovation

(1) Battery over-discharge protection circuit is simple and flexible to use. Simply select a higher supply voltage comparator, and can be applied to any of the voltage level of the circuit; simply by changing the resistance value can be set arbitrarily turned on and shut-off threshold, and thus can have a wide safety range.

(2) In the control system, the lighting power supply and chip operating power separately, the battery power supply shunt regulator handle separately, in the use of the small power relay automatically select the appropriate voltage, a small voltage is supplied to the chip work, a large voltage supplied to the lamps lighting , to avoid the use the same large voltage supplying the generated power loss. Lighting circuit at the same time, avoid the use of larger power transistor switch, but the use of SCR.

(3) The design of backup power, continuous extreme weather conditions, the battery power runs out, the lack of timely charging backup power inverter  supply, you can automatically turn on the street lights work properly.

3 Conclusion

The solar street lighting intelligent control system design, urban environmental protection, energy-saving lighting, ease the tension in the case of conventional energy sources have positive significance. The entire system runs are automatic control, the working principle is simple, easy to install, reliable technology. Scope: on the one hand, focus on mining roads, landscape lighting, as well as possible future promotion of solar system area network powered applications, technology and market promising. On the other hand, in certain occasions obvious (islands, scenic hilltop, remote locations, etc.), application advantages, including demonstration and application of positive significance, so the study makes sense.