The solar charging controller in off-grid solar power generation system is specially designed to provide intelligent charging and discharging management for storage battery. The solar charging controller adopts PWM constant voltage charging mode, which can effectively protect storage battery and increase its service life.
1.Application occasion
It can be widely used in off-grid solar power supply systems such as family, school, street, station, power station, pastoral area, field and so on.
2.Functional characteristics
(1)MCU Intelligent Control, Excellent Performance. (2)The control circuit is completely isolated from the main circuit, which is safe and reliable. (3)Intelligent battery charging management to prolong battery life. (4)Simple and concise LED display shows the operation status of the equipment at a glance. (5)Wide temperature range, high altitude.
3.Tecchnical requirement
(1)Maximum charge-discharge current: 10A~60A (2)Rated DC Voltage: 12V/24V/48V (3)Solar maximum charging voltage: 18V/36V/72V (4)It has anti-backconnection protection, battery overcharge, over-discharge protection, solar panel backconnection protection, lightning protection.
1.Adopt advanced MCU microprocessor control technology. 2.12v/24v self detect to choose output voltage. 3. Advanced MPPT technology, High converting efficiency higher than 97% for minimizing energy loss. 4.Capable of selecting different charging mode for various type of batteries 5.capable of connecting additional DC load for wide applications. 6.Three stage charge control system(bulk , absorption, and float mode)with optional temperature compensation. 7.LED indicators display charge status in real time. 8.Pulse Width Modulation(PWM)technology combined with a multi-stage charge control algorithm leads to superior charging and enhanced battery performances.
The only way to improve the efficiency of the inverters is to reduce the losses. The main losses of the solar inverters come from IGBT, MOSFET and other power switches, as well as magnetic devices such as transformers and inductors. Loss is related to the current and voltage of components and the process adopted by the selected materials.
The losses of IGBT are mainly conduction loss and switching loss. The conduction loss is related to internal resistance and current passing through the device, switching loss is related to switching frequency of the device and DC voltage of the device.
The main loss of inductance is copper loss and iron loss. Copper loss refers to the loss caused by the resistance of inductance coil. When the current is heated by the resistance of inductance coil, part of the electric energy is transformed into heat energy, which is called copper loss because the coil is usually wound by insulated copper wire. Copper loss can be calculated by measuring short-circuit impedance of transformer. Iron loss includes two aspects: one is hysteresis loss, the other is eddy current loss. Iron loss can be calculated by measuring no-load current of transformer.
1. PV and utility power take the load at same time ( can setting ). 2. Output power factor PF=1.0 3. On/Off grid with energy storage. 4. AC charging and AC output time setting. 5. Charging voltage and charging current timing. 6. External Wi-Fi device optional. 7. Connected with battery optional. 8. Wide PV input range 120-450VDC. 9. MAX PV Array Power 4500W.
There are currently three technical routes. First, space vector pulse width modulation (SVPWM) is used to reduce the loss. Secondly, silicon carbide materials are used to reduce the internal resistance of power devices. Third, three-level, five-level multi-level electrical topology and soft switching technology are adopted to reduce the voltage at both ends of power devices and the switching frequency of power devices.
1.Space Vector Pulse Width Modulation (SVPWM)
SVPWM is a fully digital control method, which has the advantages of high utilization rate of DC voltage and easy control. It is widely used in inverters. With high utilization of DC voltage, lower DC bus voltage can be used under the same output voltage, which reduces the voltage stress of power switching devices, reduces the switching losses on devices, and improves the conversion efficiency of inverters to a certain extent. In space vector synthesis, there are many combinations of vector sequences. Through different combinations and sorting, the effect of reducing switching times of power devices can be achieved, which can further reduce the switching losses of power devices of solar inverters.
2.Components Using Silicon Carbide Material
The impedance per unit area of silicon carbide devices is only one percent of that of silicon devices. IGBT (insulated gate bipolar transistor) and other power devices made of silicon carbide can reduce the on-state impedance to one tenth of the conventional silicon devices. The silicon carbide technology can effectively reduce the reverse recovery current of the diode, thus reducing the switching loss on the power devices and the current capacity required for the main switch. Therefore, using silicon carbide diode as the reverse diode of the main switch is the way to improve the efficiency of the inverter. Compared with traditional fast recovery silicon reverse parallel diodes, the reverse recovery current of silicon carbide reverse parallel diodes decreases significantly, and the total conversion efficiency can be improved by 1%. After using fast IGBT, the switching speed is accelerated and the conversion efficiency of the whole machine can be improved by 2%. The efficiency of the inverter will be further improved when the SiC reverse-parallel diode is combined with the fast IGBT.
3.Soft Switching and Multilevel Technology
Soft switching technology makes use of resonance principle to make the current or voltage in switching devices change according to sinusoidal or quasi-sinusoidal law, and turn off the devices when the current crosses zero naturally. When the voltage naturally crosses zero, turn on the device. Thus the switching loss is reduced, and the problems of inductive switching and capacitive switching are greatly solved. When the voltage at both ends of the switch or the current flowing through the switch is zero, the switch is turned on or off, so there is no switching loss in the switch. Three-level inverters are mainly used in high voltage and high power applications. Compared with the traditional two-level structure, the output of three-level inverters increases zero level, and the voltage stress of power devices decreases by half. Because of this advantage, under the same switching frequency, three-level inverters can adopt smaller output filter inductance than two-level inverters, and the inductance loss, cost and volume can be effectively reduced. Under the same output harmonic content, three-level inverters can adopt lower switching frequency, lower switching loss and higher conversion efficiency than two-level inverters.
1. PV and utility power take the load at same time ( can setting ). 2. Output power factor PF=1.0 3. On/Off grid with energy storage. 4. AC charging and AC output time setting. 5. Charging voltage and charging current timing. 6. External Wi-Fi device optional. 7. Connected with battery optional. 8. Wide PV input range 120-450VDC. 9. MAX PV Array Power 4500W.
We know that the input voltage range of 12V power supply server motherboard is usually 5% positive and negative difference. If we adopt the structure of 12V bus + 12V battery BBU, it is difficult to achieve this voltage allowable range. Especially at high currents that may be as high as 23,000 amperes, the voltage drop at impedance of 1 milliohm is as high as 2 or 3 volts, and the voltage drop of copper exhaust is much higher than the voltage range of 5% or about 0.6 V. If the voltage drop is controlled by current sharing among multiple power outlets and buses, in addition to the cost and space mentioned above, additional DC/DC voltage stabilization circuit is needed to ensure the voltage reduction caused by BBU discharge. The total cost of this DC/DC voltage regulator circuit will be very high, which will also lead to the overall uneconomical system. In 48V bus structure, the main board usually has a wide range of input voltage of 36V-58V, bus voltage drop is no longer a problem, and battery BBU can be directly connected to 48V bus, without DC/DC voltage regulator circuit, so it is very easy to adopt 48V bus structure voltage allowable range.
1.Adopt advanced MCU microprocessor control technology. 2.Advanced MPPT Technology.High converting efficiency higher than 97% for minimizing energy loss. 3.Reversed current protection at night.over voltage and reverse polarity protection. 4.Capable of selection different charging mode fo various types of batteries. 5.Protection degree:IP55. 6.Industy-leading power density compact size and high reliability. 7.Doorframe designed with waterproof structure, posted on the seal and equipped with waterproof lock on the door double insulation design. 8.Cabine adopt quality galvanized sheet or aluminum coated steel sheet as material, surface coating anti-UV power. 9.Suitable for outdoor installation. 10.With remote monitoring system aperation.
Solar controller is a device used to control photovoltaic panels to charge batteries and provide load controlled voltage for voltage sensitive devices. It regulates and controls the charging and discharging conditions of the battery, and controls the output of the solar cell module and the battery to the load according to the power demand of the load. It is the core control part of the whole solar power supply system. It is specially designed for the power supply system of telecom communication or monitoring equipment in remote areas. The charge control and load control voltage of the controller are fully adjustable, and the battery voltage, load voltage, solar array voltage, charge current and load current can be displayed.
Almost all solar power systems powered by batteries need a solar charge and discharge controller. The function of the solar charge and discharge controller is to regulate the power from the solar panel to the battery. Battery overshoot, at least significantly reduces battery life, and at worst damages the battery until it fails to function properly.
Solar controller adopts high-speed CPU microprocessor and high-precision A/D analog-to-digital converter. It is a microcomputer data acquisition and monitoring control system. It can not only collect the current working status of PV system in real time, get the working information of PV station at any time, but also accumulate the historical data of PV station in detail, which provides an accurate and sufficient basis for evaluating the rationality of PV system design and testing the reliability of system components. In addition, the solar controller also has the function of serial communication and data transmission, which can centralize the management and remote control of multiple photovoltaic system sub-stations. The solar controller usually has 6 nominal voltage levels: 12V, 24V, 48V, 110V, 220V and 600V. At present, the controller is developing towards multi-function. There is a tendency to integrate traditional control parts, inverters and monitoring systems.
1. Intelligent maximum power point tracking technology increases efficiency 25%~30% 2. Compatible for PV systems in 12v, 24v or 48v 3. Three-stage charging optimizes battery performance 4. Maximum charging current up to 60a 5. Maximum efficiency up to 98% 6. Battery temperature sensor (BTS) automatically provides temperature compensation 7. Support wide range of lead-acid batteries including wet, AGM, and gel batteries 8. Multi-function LCD displays detailed information
