The pv inverter is the heart of every PV plant; it converts direct current of the solar panels into grid-compliant alternating current and feeds this into the public grid. At the same time, it controls and monitors the entire plant. This way, it ensures on the one hand that the PV modules always operate at their radiation- and temperature-dependent maximum power. On the other, it continually monitors the power grid and is responsible for the adherence to various safety criteria.
What is solar pv inverter?
A PV inverter is a type of electrical converter which converts the variable direct current (DC) output of a photovoltaic (PV) solar panel into a utility frequency alternating current (AC) that can be fed into a commercial electrical grid or used by a local, off-grid electrical network. It is a critical balance of system (BOS)–component in a photovoltaic system, allowing the use of ordinary AC-powered equipment. Solar power inverters have special functions adapted for use with photovoltaic arrays, including maximum power point tracking and anti-islanding protection.
The Right Inverter for Every Plant
A large number of PV inverter is available on the market – but the devices are classified on the basis of three important characteristics: power, DC-related design, and circuit topology.
1. PV Inverter Power
The available power output starts at two kilowatts and extends into the megawatt range. Typical outputs are 5 kW for private home rooftop plants, 10 – 20 kW for commercial plants (e.g., factory or barn roofs) and 500 – 800 kW for use in PV power stations.
2. Module wiring.
The DC-related design concerns the wiring of the poly or mono solar panels to the inverter. In this connection, distinctions are made between string, multistring and central inverters, whereby the term “string” refers to a string of modules connected in series. Multistring inverters have two or more string inputs, each with its own MPP tracker (Maximum Power Point, as MPPT). These make a particularly sensible choice when the PV array consists of differently oriented subareas or is partially shaded. Central inverters only have one MPP tracker despite a relatively higher power output. They are especially well-suited for large-scale plants with a homogeneous solar generator.
3. Circuit topology
With regard to circuit topology, distinctions are made between one- and three-phase inverters, and between devices with and without transformers. single phase inverters are usually used in small plants, in large PV plants either a network consisting of several single phase inverters or three-phase inverters have to be used on account of the unbalanced load of 4.6 kVA. However, transformers serve the purpose of galvanic isolation (required in some countries) and make it possible to ground the PV module (necessary for some types of modules). Whenever possible, however, inverters without transformers are used. They are a little smaller and lighter than transformer devices and operate with a higher efficiency.
6 Reason for Choosing PV Inverter
Power Capacity
The solar inverter power capacity in watt, and it refers to how much power it can provide. In the market there are many different standard inverter capacities, for different applications whether its residential, commercial or industrial application. For example, the residential solar inverter power capacities exist on the market are 1000W, 2000W, 3000W, 4000W, 5000W, 6000W, 8KW and 10KW.
PV Inverter Voltage
The solar inverter startup voltage, it refers to the lowest DC voltage value in which the inverter will start running and converts DC power to AC power, in other word, at what level of sunshine the solar inverter will run. The startup voltage depends on the inverter power capacity and its brand and it usually vary from 95V to 500V.
Surge
The solar inverter surge/inrush power capability, it refers to how much power it can deliver and how long it can withstand at starting period for motors and others which requires much power at starting period. For example, the motors pull approx. 6 times “larger” its rated power capacity at starting period, and this lasts from 1-5 seconds.
PV InverterEfficiency
The solar inverter efficiency, it refers to inverter output power to its input power ratio, in other word, the inverter internal losses. Also, how much power the solar inverter consumes when it is on idle condition. Usually solar inverter efficiency is above 90%, and most of them consume very low wattage on idle condition.
Output Waveform
Solar inverter output waveform shape, is it pure sine wave or modified sine wave? This is an important factor in indicting the inverter quality. Mind that most of loads requires pure sine wave shape for better performance.
Monitoring System
Will the solar inverter support monitoring and management software, so you can monitor the system and take corrective action when needed? How will you be able to connect to the inverter, is it via wireless router or Ethernet?
It’s really important to carefully select the best and high quality solar inverter, because this will result to higher efficiency and longer life span solar system, its meaningless to choose high quality solar panels and low quality solar inverter while solar inverter is the heart and most important part in the solar system.
