An Introduction of Solar Energy

There are nuclear reactions of fusion from "hydrogen"  into "helium"  taking place in the sun. The nuclear reactions release huge energy and radiate the energy to space continuously. This kind of energy is the solar energy.

The average intensity of solar radiation on the earth orbit is 1367kw/m2, and the earth's equatorial circumference is 40,000km, so it can be worked out that the energy the earth obtains is up to 173,000TW. That is to say that it is equivalent to 5 million tons of coal that the sun radiates solar energy to the earth per minute. The nuclear reactions of fusion in the sun can last for several billion to more than ten billion years, so it can be said that the sun is a huge, long, endless energy source, and human beings depend on the energy for living.

The energy on earth, including wind energy, hydropower, ocean thermal energy, wave energy, bioenergy and some tidal energy all come from the sun. Even the fossil fuels on earth (such as coal, petroleum, natural gas, etc.) are at bottom the solar energy that has kept in storage since time immemorial, so the solar energy in a broad sense covers a vast scope, and the narrow-sensed solar energy is confined to the direct transformation of solar radiation from sunlight to heat, electricity and chemical energy.

The solar energy is a primary energy source, and it is also renewable energy. It is rich in resources without transport, which is both free for use and non-contaminative to the environment. But the solar energy has two major drawbacks: 1. the energy flow density is low; 2. the intensity is influenced by various factors (seasons, locations, climate, etc.), so it can not maintain a constant. The two major drawbacks greatly limit the effective use of solar energy.

There is a long history for human to use solar energy. In the period of Warring States, some 2,000 years ago, Chinese people knew how to use a four-side steel mirror to focus the sunlight for making a fire, and they used solar energy to dry agricultural products. In modern times, the use of solar energy becomes increasingly widespread, which includes solar thermal utilization, solar photovoltaic utilization and solar photochemical utilization etc.

12 Volt or 24 Volt DC to AC inverters convert DC current into conventional AC electricity which can run all kinds of household products such as: kitchen appliances, microwaves, TV's, radios, computers and more. Connect one of these units directly to a battery or to a cigarette lighter and plug your AC devices anywhere!

An inverter converts the DC electricity from sources such as batteries, solar panels or fuel cells to AC electricity. The electricity can be at any required voltage; in particular it can operate AC equipment designed for mains operation, or rectified to produce DC at any desired voltage.

When designing, we consider the following,

Wellsee solar inverter is a critical component in a solar energy system. It performs the conversion of the variable DC output of the Photovoltaic (PV) module(s) into a clean sinusoidal 50- or 60 Hz AC current that is then applied directly to the commercial electrical grid or to a local, off-grid electrical network. Typically, communications capability is included so users can monitor the inverter and report on power and operating conditions, provide firmware updates and control the inverter grid connection. Depending on the grid infrastructure wired or wireless (Bluetooth, ZigBee/IEEE802.15.4, 6loWPAN) networking options can be used.

At the heart of the inverter is a real-time microcontroller. The controller executes the very precise algorithms required to invert the DC voltage generated by the solar module into AC. This controller is programmed to perform the control loops necessary for all the power management functions necessary including DC/DC and DC/AC. The controller also maximizes the power output from the PV through complex algorithms called maximum power point tracking (MPPT). The PV maximum output power is dependent on the operating conditions and varies from moment to moment due to temperature, shading, soilage, cloud cover, and time of day so tracking and adjusting for this maximum power point is a continuous process. For systems with battery energy storage, the controller can control the charging as well as switch over to battery power once the sun sets or cloud cover reduces the PV output power. The controller contains advanced peripherals like high precision PWM outputs and ADCs for implementing control loops. The ADC measures variables, such as the PV output voltage and current, and then adjusts the DC/DC or DC/AC converter by changing the PWM duty cycle.

Communications on a simple system can be handled by a single processor, more elaborate systems with complex displays and reporting on consumption and feed-in-tariff pay back may require a secondary processor, potentially with ethernet capability like the Stellaris Cortex M3 parts. For safety reasons, isolation between the processor and the current and voltage is also required, as well as on the communications bus to the outside world.

We provides whole series inverters of our own brand for all industries; high stability, small, low noise, easy-operated, competitive price and high efficiency are the main characteristics of our products. Also, LCD and other accessories are options for our customers.

We are a supplier of renewable energy products and services. We are driven by a passion for high quality, high performance and high reliability. We strive to provide our customers with the highest level of support for all of the solar and wind products and services we supply.

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