Thursday, 13 December 2018

Charge Controllers PWM Vs MPPT


Charge Controllers are the devices which control the input Voltage and current.The applications vary from Solar, Wind or  UPS backup systems etc.These Charge controllers are introduced due to a specific purpose that is to restrict the unwanted spikes in current or voltages to a Battery or other devices so as to protect the Battery from damage.
There are types of Charge Controllers mainly PWM vs MPPT.The PWM(Pulse Width Modulation) is the oldest way of controlling the I-V characteristics and the later is the MPPT(Maximum Power Point Tracking) is the newest addition to improving the battery life.
If the Solar Panel Output cannot be controlled then the battery connected without charge controller will get damage due to uneven output and there is a chance of overcharging that leads to the blasting of battery in extreme cases.
What is PWM Charge Controller?
                                 Related image
PWM refers to Pulse Width Modulation Charge Controller, is a tested and old technology for charging Batteries.The PWM works by matching the battery Voltage by Pulling down the Panel Voltage.
Consider a 100W,12V Solar Panel; At Peak Hour the Solar Panel can produce approx 18V Output Voltage and 5.6A Current Which equals 100.8W.
Consider we have to charge 1 No of 12V & 20AH Battery, then the PWM will bring down the Panel Voltage from 18V to 12V to charge the battery, so 6V is getting Wasted and also the power received by the battery is to be 67.2, not 100W.Thus the efficiency of PWM is Less.
But it is one of the cheap and best charge controller to protect the battery from overcharging.Consider buying Charge Controllers according to your need and Cost for example for cold climates PWM is best suitable than MPPT.
What are MPPT Charge Controllers?

                                    Related image
MPPT refers to Maximum Power Point Tracking Charge Controllers which is the new technology developed to increase the efficiency for charging the battery and it works by tracking the maximum power(I-V) at Δt.Unlike PWM the MPPT controller does chop the Voltage but the same proportion of Current will be brought up so as to maintain the output power level.
For Example:
Consider a 100W,12V Solar Panel; At Peak Hour the Solar Panel can produce approx 18V Output Voltage and 5.6A Current Which equals 100.8W.
Consider we have to charge 1 No of 12V & 20AH Battery, then the MPPT will bring down the Panel Voltage from 18V to 12V to charge the battery and also increase the Current level to 8.4A to maintain the power level of 100W.Thus no power loss.

Image result for pwm vs mppt

Thursday, 19 October 2017

What is MCB & How it Works?

MCB refers to (Miniature Circuit Breaker) is a device which protects the electrical system from the abnormalities due to overcurrents and protects the load connected to the system.
Now da days various ranges of MCB’s are used from 6A to 16KA in Various domestic, Commercial and Industrial Sectors.Sometimes MCB’s can be called as switches due to the ON/OFF operation, The switching has to be done by manually; under a faulty condition, the switch or the operating lever will trip automatically and after fault cleared the operating lever has to bring normal by manually.

The electromechanical device has 2 arrangements;
The Thermal arrangement of the MCB is to protect from OverTemperature Faults, it has bimetallic strips which in turn actuates the contactor or latch to trip the supply.Generally, bimetallic strips are made from Brass and steel.Under the Faulty condition, the bimetallic strip got heated and bend from one side to other due to the difference in temperature and in turn trip the latch.The MCB while tripping will create arcs in order to suppress the arc the Arc Runner and Arc Splitter employed, below is the illustration.

The Magnetic Arrangement of the MCB works when an overcurrent detected the solenoid get magnetized and in turn trip the latch to protect from the overcurrent.Once the contactor got separated the arc will produce and it will pass to arc runner and finally quenched after arc splitter(arc chutes), The arc chute consists of series of chambers which will cause the arc to split and losses the energy.
The MCB’s are made for different pole ranges from single, double, triple and four pole variants as the application demands.The tripping current capacity of the device also varies for a different application.
Need to Know More? Click the link below;

What is a Diode?

Rectifiers are the device which converts AC(Alternating Current) int0 Direct Current.The conversion requires a device which can perform those operations are called Power Diodes.
The example of a rectifier is Power Diode which allows current in one direction only from its anode to cathode(forward direction) and blocks in the backward direction due to its semiconductive properties.
Rectifiers are the device which converts AC(Alternating Current) int0 Direct Current.The conversion requires a device which can perform those operations are called Power Diodes.
The example of a rectifier is Power Diode which allows current in one direction only from its anode to cathode(forward direction) and blocks in the backward direction due to its semiconductive properties.

The Diode is made of Silicon or Germanium; P and N-type were made by adding impurities to the silicon which will be either trivalent or Pentavalent element.
The Process of adding impurities to the semiconductor is known as Dopping.
If the applied voltage more than the barrier voltage of the Diode then the diode will conduct in the backward direction also.
From the above Fig, we can see that the battery Positive is connected to the  Anode and Negative is connected to the Cathode, The P side of the Diode is rich in holes and deficit in electrons Vice versa for N Side. Before applying any voltage Depletion layer will form between P and N Sides due to Thermal excitation.
UnBiased Condition:
Before applying any voltage Depletion layer will form between P and N Sides due to Thermal excitation.The thermal excitation influence the holes movement from P side to the N side and electrons movement from N side to P side.The holes will recombine with the electrons in the N side and the electrons will combine with the holes in the P side this effect creates an immovable region in which all the movement of electrons and holes are seized.This process is called diffusion. The P side will have immovable -ion and N side will have +ve immovable ion which causes static electric field in the depletion region.
Forward Biased Condition:

When the Diode is forward biased; the Positive end of the battery connected to the P side( Anode) and the Negative terminal of the battery connected to the N side of the diode(cathode), is the movement of electrons, causes the flow of current in the diode but there is a depletion region in the diode(P-N Junction) where there are no any free electrons but when we apply an external voltage then the voltage is higher than the barrier voltage the diode will conduct.
The Barrier Voltage of the Silicon Semiconductor is 0.7V and for Germanium is 0.3V,  Assume the Voltage of the external Source is 0V; Unless until the forward Voltage to the diode reaches 0.7V the diode won’t conduct any current.When the Forward Voltage of the diode is more than the barrier voltage then only the diode will start conducting current.The time taken to overcome the barrier voltage of the diode is known as the Recovery Time.
Reverse Biased Condition:
When the Diode is Reverse Biased; Positive terminal of the battery or source is connected to the cathode or N side of the diode and the Negative terminal of the Battery is connected to the P-Side of the Diode or Anode then the Depletion Zone become much wider that no current will flow, but actually a small amount of current will still flow from N type to P type that’s due to the minority charge carriers.

 The Diodes maximum reverse biased voltage without breakdown is known as Peak Inverse Voltage (PIV), if we keep on increasing the reverse voltage then at one stage the depletion region will be destroyed due to the flow of huge reverse current; the Diode also will get destroyed permanently.This breakdown is known as Avalanche Breakdown.The PIV is linked with the temperature also as Temperature increases the PIV increases and vice versa.
Avalanche BreakDown: When the applied reverse voltage is higher than the breakdown voltage than the depletion region will get destroyed then due to higher potential the free electrons get energised with kinetic energy kicks the atoms of the device to accumulate more electrons by breaking the covalent bonds, thus the accumulation of huge electrons causes the flow of huge current then the Diode will get destroyed eventually.

Tuesday, 20 September 2016

Know about Harmonics and its Effects

Harmonics are the deviation or the distortion of the waveform of its Sinusoidal waveform due to the addition of waveforms of different frequencies.
As per Ohms Law V=I/R,Voltage is proportional to the Current means Current also have a sine waveform except current(which has power factor) does not align perfectly to voltage waveform.
                                         current waveform,voltage waveform,sinewave

The Power supply operates at a standard of 50Hz that means 50Cycles per sec,the voltage changes from positive and negative polarity and back again 50 times per sec.The below is the sinewave of the supply in that the voltage(240V) changes between +240 to -240V thus called alternating voltage.

Figure 2 shows the superimposition of the 3rd order harmonic to the base sine wave due to that the resultant waveform is Distorted waveform(Base+3rd Harmonic).The entire waveform does not follow the Sinusoidal pattern causes unbalance in the load.

                                     sine waveform,supply waveform

Waveform with superimposed harmonics,3rd harmonics,2nd harmonics
The below Fig shows the distorted waveform which is the resultant of the addition of the 3rd harmonic with the fundamental pure sinewave.
Fundamental to Distorted harmonics waveform

The below fig shows the Sine Wave from the Source without harmonics and the fig shows only one cycle having Vmax is the Peak value,Frequency f in Hz and Time period T.

                                    Sinewave of the power supply

The Equation of a Sinewave is written as:


Note: The harmonics depend on Phase angle,Frequency and also the amplitude.
If the fundamental frequency is given as; E = Vmax(2πƒt),then the complex waveforms will be,


Complex WaveForms due to Harmonics

                       Complex waveform due to the addition of harmonics                   
Harmonic Sequencing

From the below table, Fundamental frequency is either 50Hz or 60Hz. And the 2nd order harmonic frequency will be 100Hz or 120Hz ,the 3rd order harmonic frequency is 150Hz or 180Hz and so on...,

The harmonics are voltages or currents that operate at a frequency that is an integer multiple of the Fundamental Frequency.

Frequency, Hz

Note that in some countries the fundamental frequency will be either 50Hz(UK) or 60Hz(US).

Harmonic Effect
Excessive Heating Effect
Motor Torque Problems
Adds Voltages and/or Currents in Neutral Wire causing Heating

Common Problems Caused by Harmonics

Overloading Neutral Conductors
The 3-phase system consists of three phase conductors and a neutral conductor. These three phase conductors carry the same amount of current and they used to cancel each other in the neutral conductor makes the load balanced But due to the usage of motors,fans,rectifiers,SMPS causes neutral with increased or twice the current flow of phase current.Hence with balanced load with the currents cancel each other in the neutral conductor, the size of the conductor is minimum, but due to the nonlinear loads, the current draw is higher hence the size of the neutral conductor is bigger than the counterpart.

Overheating Transformers & Losses
The Transformers feeding power to the unbalanced loads like rectifiers,motors, the eddy current loss in the windings is proportional to the square of harmonic current and its frequency thus the losses associated with the transformer with the non-linear load will be twice of the linear load.This condition leads to the overheating of the Transformer which degrades the insulation causes complete failure.

Nuisance Tripping of Circuit Breakers

The RCCB used to check the current between phase to neutral if the neutral current is not same with the phase current then RCCB disconnects power to the Load and also RCCB does not sum the higher frequency components thus sometimes it used to trip.

Thursday, 4 August 2016



RCCB refers to Residual Current Circuit Breaker which is a rival to the ELCB(Earth Leakage Circuit Breaker). As both the circuit breaker works for the same cause but the difference is RCCB connectivity is different also it gives better protection over ELCB.

ELCB is a voltage operated device which has Line,Neutral, and Earth Connections detects potential in the earth when the voltage is non-zero and indicates that there should be a leakage current in the earth and it protects by tripping.The ELCB can protect from earth fault only  and doesn't provide protection from overload and short circuit so better opt for RCCB than ELCB.

Meanwhile, RCCB which has Line and Neutral connections and the working is when there is a difference in current level from Line to neutral indicates a fault or earth leakage and it trips.As line current always equal to the neutral current which flows back in neutral conductor any difference in current means that somewhere earth fault occurs so the RCCB will get tripped.

The RCCB doesn't require earth connection so that even it can provide shock or fault protection to the device which does not have the earth of its own.

The Tripping of the RCCB is within 30milliSeconds of the earth fault.
The widely used RCCB rating is 30mA and 100mA.
The Human body can withstand up to 30mA.

Like ELCB, RCCB doesn't protect from the following,

1.Overload(Due to huge current even undetected).
2.Nuisance Tripping(Due to sudden changes in electrical load like switching Airconditioner or Motor etc...)
3.Non-Standard Waveforms(Not guaranteed for the operation by other than nominal waveforms like from halfwave rectifiers).
4.Short Circuits(Due to Line-Neutral Schock).

Friday, 10 June 2016

Best institute for Solar Training In India

solar course,solar training,solar training institute,solar power system training,certified solar traineer


                             MSME is a branch of Indian Government,Which is the body for the formulation and administration of rules,regulations and laws for micro,medium and small enterprises.This is providing Employment and training for the peoples to create a skilled workforce in emerging India. The MSME approved institutes are there in every state and the details can be accessed from mnre website.

Location: New Delhi


                        Gujarat Energy Research & Management Institute (GERMI) promoted by Gujarat State Petroleum Corporation Ltd. (A Govt. of Gujarat Undertaking). GSPC is a fully integrated energy company having a presence in various operations like Exploration & Production, Transportation of Gas, and Power Generation, IT services. It is one of the fastest growing state owned companies and has excellent support from Gujarat Govt. as well as from Central Govt.

It has already established a specialised technology & management institute focusing on the Oil & Gas Sector and is actively pursuing initiatives in the areas of research and alternative energy resources.

Location: Gujarat, India
Phone: +91 079-66701362

The Primary objective of NPTI includes the below mentioned functions;

1.Operation and Maintenance of Power Stations.
2.All other aspects of Electrical Energy Systems including Transmission,Sub-Transmission and distribution
3.To act as an apex body for initiating and coordinating training programs in the Power Sector of the country
4.To establish and run Training Institutes for Engineers, Operators, Technicians and other personnel of the Power Sector.

Location: Faridabad, India
Phone: 9818897666

The National Centre for Photo-voltaic Research and Education (NCPRE) at IIT Bombay was launched in 2010.For the Jawaharlal Nehru National Solar Mission (JNNSM) to succeed, the availability of trained manpower is a prerequisite. NCPRE aims to provide the framework to meet this need.

1.Design and run appropriate post-graduate programmes in PV at IIT Bombay.
2.Design and offer appropriate undergraduate programmes and courses in Energy at IIT Bombay
3.Create appropriate course modules, including laboratory modules, which can be replicated at other institutions and universities.
4.Train teachers at other institutions and universities.
5.Offer IITB's courses through distance education channels.
6.Design and run special programmes (including certificate-level and diploma programmes) for industry personnel on a part-time basis.
7.Run short-term continuing education programmes for industry personnel
8.Train master trainers for teaching technicians.
9.Provide access to a running fabrication and characterisation facilities for researchers and industry users.

Location: Mumbai, India
Phone: +91 22- 2576 4476 ; 4480 ;4479


The Gujarat Energy Development Agency's an ISO 9001:2008 certified educational institute that provides technical training Programs on Solar energy.The major objective of the institute is to produce solar energy skilled manpower. 

GISE has set the pace of Renewable Energy Development in the country with the foundation laid for Asia’s first Solar Park that envisaged an investment of Rs. 7500 crore. The Solar Park will be established on 2,000 ha of arid land in Village: Charanka (Taluka: Santalpur Taluka) District Patan bordering Pakistan. Plots have been allocated to 16 Private investors to generate to 176 MW solar power.

Courses Offered
Course NameDurationEligibility
Diploma in Solar System & Inverter Installation & Servicing1 Year (Short Term)12th Passed (Any Stream) / ITI
Diploma in Solar System & Environmental Engineering6 Semester12th Passed (Any Stream) / ITI
B.Tech in Solar & Environmental Engineering8 Semester10+2(Science + Maths)
B.Tech in Solar & Environmental Engineering
(Lateral Entry to 3rd Semester)
6 SemesterPolytechnic Diploma of 3 year after 10th Class in Solar & Environmental Engineering4 SemesterPassed in B.E./B.Tech
Certificate in Solar Photo-voltaic Application , Design & Technology3 MonthsPassed in Diploma, Bachelor or Master in Any Stream
Solar Technical Workshop3 DaysPassed in 12th , Diploma, I.T.I, Bachelor or Master in Any Stream

Location: Gujarat, India
Phone: 079 – 2768 01 22


The National Institute of Solar Energy (formerly Solar Energy Centre) was established by MNRE in 1982. NISE is an autonomous institute under Ministry of New and Renewable Energy, Government of India established to facilitate the Research & Development, Testing, Certification, Skill development activities in the field of Solar energy technologies.

NISE also supports the ministry in the implementation of prestigious National Solar mission. The institute is committed to the development and demonstration of solar energy related technologies and its applications to the common man in the country.

Location: Gurgaon, India (Campus)
Telefax: 0091-124-2579207
E-mail: sec.nic@in


Mithradham also offers student internship training in renewable energy. The aim of the training programme is to offer hands on training on the core concepts necessary to work with all PV systems, including system components, site analysis, PV module criteria, mounting solutions, safety and commissioning. We train decision makers, technicians, and end-users in order to create sustainable renewable energy projects

The present programme offers a one week training with German experts who have international exposure and expertise in on-grid and off-grid solar P-V. It is tailored to all who have a basic knowledge in electricity and intend to make use of it. Practical installation and study visits to different solar installations are also offered as a part of the programme. Consultancy services of the expert is available by prior appointment during the training programme.

A certificate will be issued at the end of the training programme. The following are the areas of theoretical and practical training:
  1. Basics of solar energy
  2. Stand alone PV systems: Planning, Designing and Installation
  3. Grid connected systems
  4. Solar cable technology
  5. Maintenance and Surveillance of PV installations
Location: Kerala, India
Phone: +91(0)484 2839185


GSES is leading the industry in providing accredited solar training for the safe design and installation of grid connected solar systems. It offers solar training and renewable energy courses to cater to a broad range of students. Their courses include:
  1. Grid Connected PV Systems Design and installation (Online and face-to-face)
  2. Standalone Solar PV Systems Design and Installation (Face-to-face)
  3. Rooftop PV Systems Design and Installation (Face-to-face)
  4. Solar PV Best Practices (Face-to-face)
  5. Solar Power System Fundamentals (Online)
  6. Solar PV course for Startups and Entrepreneurs (Online and face-to-face)
Location: New Delhi, India
Phone: +91 1140587622


            PRINCE (Promoters and Researchers In Non-Conventional Energy) provide "Entrepreneurship Training in Renewable Energy". This includes hands on/Field training as well as classroom sessions. Many entrepreneurs in solar concentrating cookers, Scheffler concentrators are their trainees.

Location: Maharashtra, India
Phone: 91 2562 271795

Thursday, 11 February 2016

Lithium ion batteries

Lithium ion battery,aviation battery,LI-Ion battery,battery,telecom battery

Lithium ion batteries,These batteries are now becoming popular especially in telecom sectors,Space projects etc...because of their charging and discharging feature,Compact,energy density and finally the monitoring feature involved in Li-Ion batteries.

Working of a Battery?

The batteries is a storage device,that converts chemical energy.The batteries are having 3 major parts or components.Anode(negatively charged),Cathode(Positively charged) and Electrolytes.

For example,Take one container and fill it with diluted sulfuric acid as the electrolyte. Now immerse zinc and one copper rod in the solution and connect them externally by an electric load. Now your simple voltaic cell is completed. Current will start flowing through the external load.

Zinc in diluted sulfuric acid gives up electrons as below:

These Zn + + ions pass into the electrolyte, and their concentration is very high near the zinc electrode. As a result of the above oxidation reaction, the zinc electrode is left negatively charged and hence acts as cathode. The diluted sulfuric acid and water disassociate into hydronium ions as given below:

Due to the high concentration of Zn + + ions near the cathode, the H3O+ ions are repelled towards the copper electrode and get discharged by removing electrons from the copper atoms. The following reaction takes place at the anode:

As a result of the reduction reaction taking place at copper electrode, copper is left positively charged and hence it acts as the anode.

Lithium ion battery,aviation battery,LI-Ion battery,battery,telecom battery,working of battery

Lithium ion Battery?

These batteries having better features compared to other lead acid or other batteries because there will be a monitoring section provided which can give you all real time data's at that time, means Voltage of individual cells,battery pack,total voltage,cell temperature,Over current or Under current etc...., each and every parameters of the battery including SOH and SOC also tracked using the in-build BMS(Battery Monitoring System).

The Lithium ion batteries have high energy density, means the amount of energy stored per unit volume is higher than the traditional Lead acid batteries so that the size of the battery was compact too.

The Li-Ion is a lightweight metal so that it is easy to form ions at the time of chemical reaction,The Li-ion battery can store as much as twice of the power Lead Acid battery can hold and also these batteries are also environmentally friendly but susceptible to 100% discharge so 80% discharge is recommended.

Let us take an example of 48V/75AH Li-Ion battery,so it has 15 no of 3.2V cells connected in series,thus makes you 48V battery.thus for the same size it give twice the power of other battery types.

These batteries have some modern electronics involved to better understand each and every parameters,so mainly BMS (Battery monitoring system),Contractors,Temperature sensors,Shunt,RS485,Data Logger,CAN.

The BMS may contain MOSFET to replace contractors which are responsible for charging and discharging,The BMS can able to control the battery from fail due to any Over or Under current/Voltage/Temperature,also it has alarms in case of any problems occurred so that these BMS are very helpful to protect batteries by monitoring all possible parameters.

RS485 which is used to monitor the parameters by connecting PC/Laptop.CAN communication is used to communicate between each battery so that the data logger can store the data of all the batteries.Data logger is used to log all the parameters of the battery and generally the Master module hold data logger and CAN communication allow to get information from each battery.

Lithium ion battery,aviation battery,LI-Ion battery,battery,telecom battery,working of battery
The commercially used negative electrode is graphite and  positive electrode will be one of these three materials- lithium cobalt oxide, a polyanion-such as lithium iron phosphate or a spinel -such as lithium manganese oxide.The electrolyte will be a mixture of some organic carbonates such as ethyliene carbonate or diethyl carbonate containing complexes of Li ions,


The external voltage was given through any external charger with the same polarity is applied between the electrodes, thus the charging process will start. The lithium atoms leave the metal oxide structure and ionize into Li+ ions under the release of an electron of each one. In this process Li+ ions diffuse to the negative electrode(anode). At the surface of the graphite particles the Li+ ions and electrons recombine with each other forming neutral lithium atoms and are reintercalated into the molecular structure of the graphite particles,otherwise Lithium is deposited in the anode.When no more ions will flow, the battery is fully charged and ready to use.

Ref:TUM EES YouTube Channel


During discharge, lithium atoms oxidize by forming Li+ ions and electrons, whereas Li+ ions move to the positive electrode diffusing through the electrolyte and the separator. The electrons flow from the negative electrode to the positive on the external circuitry, where the resulting current flow can be used for an application. At the positive electrode the electrons recombine with the Li+ ions and are stored in the molecular structure of the active material, otherwise Lithium is deposited in the cathode.When all the ions have moved back, the battery is fully discharged and needs charge again.