Unique solution required for grid-tie inverters in India!

July 27, 2010

According to Venkat Rajaraman, CEO, Su-Kam Power Systems, there is a need for a unique solution for grid-tie inverters in India. The reason being: the grid itself is unstable, and isn’t available most of the time. Also, it does not comply yet, to any of the known specifications.

He was speaking during a workshop on solar inverters, organized by the India Semiconductor Association (ISA) on 23 July, 2010, in Kolkata, India.

Challenges and opportunities for solar inverters in India
Rajaraman listed some other challenges as well facing the Indian solar inverter industry. These include a need for solar charge controllers that can take advantage of the existing inverters/HUPS that are already installed for off-grid applications. Also, there is a reqirement of low-cost, high-efficiency charge controllers (MPPTs) that can work with a variety of batteries.

Further, the inverters (solar/otherwise) are still designed with chips designed for motor control application. There is a need for inverter specific solution input PFC, battery monitoring/algorithms, charge current/mains sense, power device drivers, etc).

As and when these challenges be met, which should happen, hopefully, in the long run, the Indian opportunity is immense! For instance, the goal of the Jawaharlal Nehru National Solar Mission (JN-NSM) is already well known — to set up a capacity of solar power generation of 20,000 MW by 2022 in India.

Solar should be seen as a long term solution to solving India’s power deficit situation. The total capital outlay at today’s prices for adding 20,000MW capacity is estimated at Rs. 4 lakh crores ($90 billion)! Further, the share of electronics (balance of system) alone will likely be Rs 80,000 crores ($20 billion).

Solar inverters – R&D, future needs
Rajaraman also highlighted the R&D efforts going on in India as well as the future needs for solar inverters. As far as R&D is concerned, IIT-Mumbai boasts of a “Center of Excellence in PV.” We need a network of CoEs.

Next, the MNRE has a PV Research Council, which features industry experts, scientists, researchers, representatives, etc. There is also a CIIE (Center for Innovation, Incubation and Entrepreneurship) at IIM, Ahmadabad. Besides, there are innumerable solar start-ups in the country, who are also doing research in their own ways.

Highlighting the future needs for India, Rajaraman said that there is a pressing need to create a critical mass of researchers, as it is important to fill the link between the lab to plant.

India would also do well to engage in pre-competitive collaborative research through either the open domain or a consortium model. Some key research areas could be cost effective power electronics – MPPTs, micro inverters, etc.

There should also be particular focus on batteries and storage technologies. Lastly, there is need for innovative solutions, and especially, business models.

While the first generation of players looked at early adoption and technology proofing, the second generation has focused on repeatability and efficiency. The third generation needs to focus on scaling up. Rajaraman also called upon to customize the PV inverter testing standards for India.

Focus on new technologies
There is also a need to focus on new technologies. Some of these would be:

* Multi-string inverters – a single inverter to convert power input from several module strings, reducing inverter costs for PV systems.
* Maximum Power Point Tracker (MPPT) for each string, ensuring maximum energy yield.
* Modularity and N+1 redundancy.
* Improve mean time between failures (MTBF) to give better reliability.
* Improved higher KVA product range.
* Minor KVA adjustments in the lower end inverters.
* HF solar inverters.
* Micro inverters for maximizing the efficiency.
* Grid interactive solar inverters to be a part of the solar Power generation play – will be the dominant business in the coming years.

  1. Shilpa Urhekar
    July 28, 2010 at 10:59 am

    One very interesting application which can revolutionize the Indian inverter industry is the one of “Hybrid Inverters”. These are the ones which can support both solar and wind. Industries like Telecom and Railways would benefit immensely with these inverters,especially for the remote locations. Huge savings of DG fuel and ease of operation can transform these sites to virtually unmanned stations!

  2. Suman
    September 7, 2012 at 2:38 pm

    Solar inverters have to be tested for their MPPT under different I-V ratings and weather conditions such as irradiation, temperature settings, temperature co-efficiency, sunny-cloudy-sunny-darkness, solar cell material fill factor, etc.

    We have provided solutions for MPP tracking of solar inverters in research & design stage in India to various organizations, viz. SEC, TERI, Universities, etc.

    Thanks to Mr Pradeep for throwing light on very useful & important aspects of solar inverters.

  3. Prashant
    May 8, 2014 at 1:47 pm

    True. Pure grid-tied inverters will work in Mumbai and a handful of other cities where the grid is fairly reliable. Otherwise, it won’t work. It would have to have a backup facility to ensure that the power produced during the period of grid failure is stored and you get the most out of the PV modules. However, then that means that you need to have batteries as part of the installation, which increases the upfront cost of installation and also bring recurring costs i the picture.

    So this is a big issue for sure…We are also working on various initiatives and are hopeful that some of them will bear fruit.

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