Solar energy is limited so far (at the household level) photovoltaic panels creating a relatively low power. But regardless of the structure of the photoelectric converter of the sun light in the current apparatus is equipped with a module which is called the solar battery charge controller.
Indeed, in the photosynthesis system scheme sunlight enters battery - energy storage derived from solar panels. It is this secondary power source is serviced primarily by the controller.
The content of the article:
- Controllers for solar panels
- Types used in practice
- Block diagrams of controllers
- Option # 1: PWM device
- Option # 2: instruments MPPT
- Controller Connectivity
- Connection technology PWM models
- How to connect the MPPT devices
- Useful videos on the topic
Controllers for solar panels
Electronic module, called a controller for the solar battery is designed to perform a variety of control functions during the charge / discharge battery, solar energy preserving battery.
When the solar panel surface is set, for example, on the roof, the sunlight falls, the photocell device light is converted into an electric current.
The resulting energy is, in fact, could be fed directly to the battery drive. However, the charge / discharge process of the battery has its fineness (specific levels of voltages and currents). If we ignore these subtleties, the battery in a short period of operation simply fails. In order not to have such sad consequences is a module called a charge controller for solar batteries.
In addition to controlling the charging module monitors the power consumption. Depending on the degree of discharge circuit charge controller from the solar battery is regulated and set level of current required for the initial and subsequent charge.
In general, if we talk in simple language, the module provides a carefree "life" to the battery, which periodically collects and gives energy consuming devices.
Types used in practice
On the industrial level is adjusted and carried out the production of two types of electronic devices, the performance of which is suitable for use in solar power system diagram:
- PWM series devices.
- MPPT series devices.
The first type of controller for the solar battery can be called "old man". Such schemes have been developed and introduced into service the dawn of the solar and wind energy. The operating principle of PWM controller circuit is based on algorithms of pulse width modulation. The functionality of these devices is slightly inferior to more advanced devices series MPPT, but in general they work is also quite effective.
Construction, where applicable Maximum Power Point Tracking technology (tracking maximum limit power), it has a modern approach to circuit solutions provide greater functionality. But if we compare the two types of controller and, moreover, with a bias towards the domestic sphere, the MPPT devices do not look in the glowing terms in which they are traditionally advertise.
MPPT controller type:
- It has a higher value;
- It has a complex algorithm settings;
- It gives a gain in power just over a large area panels.
This kind of equipment is more suitable for the global solar energy systems.
Under normal user's needs Appliance medium having, as a rule, small-area panel, cheaper to buy and operate the same effect PWM controller (PWM).
Block diagrams of controllers
Schematic diagrams of PWM controllers, MPPT for consideration by the narrow-minded view - it is too difficult moment, conjugate with a subtle understanding of electronics. Therefore, it is logical to consider only block diagrams. This approach is favored by a wide circle of people.
Option # 1: PWM device
The voltage from the solar panels on the two conductors (positive and negative) comes to the stabilizing element and the separation resistive chain. Due to this alignment piece circuits receive the input voltage potentials and to some extent organize controller input protection from excess voltage input boundary.
It should be emphasized: each single machine model has a specific limit on the input voltage (indicated in the documentation).
Next, the voltage and current limited to a required value of power transistors. These circuit components, in turn, is controlled through the controller chip driver chip. As a result, the output pair of power transistors normal set voltage value and the battery current.
Also in the present circuit temperature sensor, and a driver control power transistor, which is adjustable load capacity (protection against deep discharge battery). a temperature sensor controlled heating state of important elements of the PWM controller. Generally the temperature level within the housing or on radiators power transistors. If the temperature is outside of the specified settings, the device disables all active power line.
Option # 2: instruments MPPT
The complexity of the scheme in this case due to its complement a variety of elements that build the necessary control algorithm more accurately, on the basis of operating conditions. voltage and current levels are monitored and compared to the comparator circuit, and a comparison of results is determined by the maximum power output.
The main difference between this type of PWM controller devices is that they are able to adjust the energy the solar module at maximum power regardless of weather conditions. Scheme of such devices are implemented several control methods:
- perturbation and observation;
- increasing conductivity;
- current sweep;
And in the final segment of the overall action applies even an algorithm to compare all of these methods.
Considering the theme of connections, it is necessary to note at once: for the installation of every single feature of the device is to work with a particular series of solar panels. For example, if a controller designed for a maximum input voltage of 100 volts, a series of solar panels should output a voltage greater than this value.
Before connecting the device, you must determine the place of its physical plant. According to the rules, the installation location should be chosen, dry, well-ventilated area. It excludes the presence near the product flammable materials.
Unacceptable presence in the immediate vicinity of the unit of vibration, heat and humidity. Place of installation must be protected from falling rain and direct sunlight.
Connection technology PWM models
Virtually all manufacturers of PWM-controllers require to follow the exact sequence of devices connect.
To connect peripheral devices needed in full compliance with the notation the terminals:
- Connect the wire to the battery terminals to the battery device in accordance with said polarity.
- Directly at the point of contact of the positive wire to include a protective fuse.
- On the controller contacts intended for solar panels, to fix the conductors exiting from the solar battery panels. Observe the polarity.
- Connect to the terminals of the device corresponding to the load test lamp voltage (typically 12 / 24V).
This sequence should not be violated. For example, to connect a solar panel primarily strictly prohibited at the non-connected battery. Such actions the user runs the risk of "burning" the unit. Also for the PWM controller series unacceptable voltage inverter connection to the terminals of the controller load. Inverter be connected directly to the battery terminals.
How to connect the MPPT devices
General requirements for the physical installation for this kind of vehicles do not differ from previous systems. But the process plant is often somewhat different, because MPPT controllers are often considered more powerful devices.
For example, for high-end systems, these requirements are supplemented by the fact that manufacturers recommend taking the cable for the power connection lines for the rated current density of not less than 4 A / mm2. That is, for example, for a controller on the current of 60 A need a cable to connect to the battery section not less than 20 mm2.
Connecting cables required to be equipped with copper tips, densely compacted special tool. The negative terminal of the solar panel and the battery must be fitted with adapters with fuses and circuit breakers. This approach eliminates the energy loss and provides safe plant operation.
Before connecting the solar panel to the instrument must ensure that the voltage at the terminals corresponds to or less than the voltage that is allowed to apply for the controller input.
Connecting peripherals to the machine MTTP:
- Switches panel and battery into the position "off".
- Remove the protective fuses on the panel and battery.
- Connect the cable to the terminal of the battery terminals for the controller battery.
- Connect the cable from the solar panel terminals controller terminals, signposted.
- Connect the ground cable to the bus terminal "ground".
- Set the temperature sensor on the controller according to the instruction.
After these steps, you need to fix it in place before the extracted battery fuse and move the switch to "on". battery detection signal will appear on the control screen.
Next, after a short pause (1-2 min) to put in place before the extracted fuse panel solar panel and transfer switch in "on" position. Display unit displays the value of voltage of the solar panel. This point indicates the successful launch of the solar energy into work.
Useful videos on the topic
Industry produces multifaceted device in terms of circuit design. Therefore, unambiguous recommendations for connection of all plants, without exception, can not be given.
However, the main principle for all types of instruments remains the same: to connect the battery without a connection controller bus with photovoltaic panels is unacceptable. Similar requirements for inclusion in the voltage inverter circuit. It should be considered as a separate module, connected to the battery in direct contact.