The LED street lamp power supply is the world's highest efficiency switching power supply up to 95%, high power factor up to 0.99, high reliability and long life, and meets the IP67 waterproof rating. It is applied to high-power lamps such as street lamps and tunnel lamps, and the product encapsulated aluminum shell has good heat dissipation effect. The selection of LED street lamp power supply (the type of LED street lamp power supply) is critical to the normal operation of the electrical control system of mechanical equipment. When choosing LED street lamp power supply (LED street lamp power supply knowledge), the factors and points we have to consider are also various. So, in the process of choosing LED street lamp power supply, which aspects should we consider? Let us step by step to understand the LED street lamp power supply.

LED street light power supply principle

The LED power supply has a circuit to control the switch tube for high-speed pass and cut-off. It converts direct current into high-frequency alternating current to transform the converter to generate one or more sets of voltages required! The reason for conversion to high-frequency alternating current is that the efficiency of high-frequency alternating current in the transformer circuit is higher than that of commercial power 50Hz or 60Hz. Therefore, the size of the switching power supply transformer can be small, it will not be very hot when the switching power supply is working, and the product price is lower than the power frequency DC regulated power supply. If you don't change 50Hz or 60Hz into high-frequency power, then the switching power supply has no meaning. Switching power supplies can be roughly divided into two types: isolation and non-isolation. Those that are isolated must have switching power converters, while those that are not isolated may not necessarily have switching power converters. Compared with the traditional DC power supply, the switching power supply has the advantages of small size, light weight, and high efficiency.

Classification of LED street lamp power supply

1. According to the driving mode, it can be divided into two categories

1.1 Constant current

a. The output current of the constant current drive circuit is constant, but the output DC voltage varies within a certain range with the size of the load resistance. The smaller the load resistance, the lower the output voltage. The larger the load resistance, the output The higher the voltage;

b. The constant current circuit is not afraid of load short-circuit, but it is strictly forbidden to open the load completely.

c. It is ideal for a constant current drive circuit to drive LEDs, but relatively speaking, the price is relatively high.

d. Pay attention to the maximum withstand current and voltage value used, which limits the number of LEDs used;

1.2 Regulated

a. After the various parameters in the voltage regulator circuit are determined, the output voltage is fixed, but the output current changes with the increase or decrease of the load;

b. The voltage regulator circuit is not afraid of load opening, but it is strictly forbidden to short-circuit the load completely.

c. The LED is driven by a voltage-stabilizing drive circuit, and each string needs to be added with a suitable resistance to make each string of LEDs show an average brightness;

d. The brightness will be affected by the voltage change from rectification.

2. Classified by circuit structure

2.1 Resistor and capacitor step-down method

When the voltage is reduced by the capacitor, the instantaneous current passing through the LED is extremely large due to the effect of charging and discharging during the flashing use, and the chip is easily damaged. It is susceptible to the influence of power grid voltage fluctuations, and the power supply has low efficiency and low reliability.

2.2 Resistance step-down method

The resistance step-down is greatly interfered by the change of the grid voltage, and it is not easy to make a regulated power supply. The step-down resistance consumes a large part of the energy, so the power supply efficiency of this power supply method is very low, and the reliability of the system is also low. .

2.3 The conventional transformer step-down method

The power supply is small in size, heavy in weight, and low in power efficiency, generally only 45% to 60%, so it is generally rarely used and has low reliability.

2.4 Electronic transformer step-down method

The power supply efficiency is low, the voltage range is not wide, generally 180~240V, the ripple interference is large.

2.5 RCC step-down switching power supply

The voltage regulation range is relatively wide, the power supply efficiency is relatively high, generally 70% to 80% can be achieved, and the application is also wide. Because the oscillation frequency of this control method is discontinuous, the switching frequency is not easy to control, the load voltage ripple coefficient is also relatively large, and the adaptability to abnormal loads is poor.

2.6 PWM control mode switching power supply

It is mainly composed of four parts, input rectification and filtering part, output rectification and filtering part, PWM voltage stabilization control part, and switch energy conversion part. The basic working principle of PWM switching regulator is that when the input voltage, internal parameters and external load change, the control circuit performs closed-loop feedback through the difference between the controlled signal and the reference signal to adjust the pulse width of the main circuit switching device. Make the output voltage or current of the switching power supply stable (that is, the corresponding regulated power supply or constant current power supply). The power supply efficiency is extremely high, generally 80% to 90% can be achieved, and the output voltage and current are stable. Generally, this kind of circuit has perfect protection measures, which is a high-reliability power supply.