Shenzhen Growatt New Energy Technology Co.,Ltd was established in 2010, focusing on providing solar inverters and system solutions for global market. Until now, Growatt has reached over 8.5GW installation worldwide, famous as a world leading manufacturer of...
Dedicated in becoming world-leading smart energy
In 2010,Growatt was founded.
In 2012, Growatt Cooperated with Sequoia Capital and China merchant.
In 2014, Growatt was the No.1 supplier of PV inverter in Thailand.
In April 2016,Growatt products have covered more than 100 countries....
Dear Customers,Partners and social friends from all walks of life,
Time flies. It has been seven years already since Growatt was founded in 2010. We always believe that it is our duty to use green energy freely and conveniently.
Growatt MAX inverter running steadily in harsh grid
the saying goes:" A person of
integrity can stand tests".
A high quality inverter also needs
to pass the harsh grid environment test. The harsher the environment, the more it
can reflect the performance of a device. Let's
take a look at a real case of our latest MAX series inverter working in a small industrial and commercial solar plant today:
power plant is installed on the roof of a steel factory
in Jiangsu, China. Installed capacity of the project is 60kWp, with a
total of 200 pieces of 300W high-efficiency MONO modules.
20 pieces in series and
total of 10 strings to connect a Growatt MAX
60KTL3 LV inverter, this inverter has up to 6 MPPTs, with string monitoring function, intelligent IV curve diagnosis capabilities and
excellent grid environment adaptability.
After on-site investigation, the actual load is
mainly crane and welding machines and other steel processing equipment, as
shown in the following pictures:
The characteristics of the load caused very poor
power quality of grid, power factor has even dropped to 0.657. In order to
improve the power factor, the steel factory puts reactive power compensation
device into operation, as shown below:
Actual field test showed that during load switching
on/off, especially when the reactive power compensation capacitor cabinet is
switched on, power grid voltage fluctuates violently far beyond the rated
amplitude value during normal operation, as shown in the following figure.
Such a harsh grid environment will cause great
surge voltage and current impact on the inverter semiconductor device, if
inverter protection function does not respond quickly enough, or protection
measures are improper, the inverter will disconnect frequently from grid or be
damaged, while the MAX series inverter is still operating steadily with
outstanding yields. The daily energy of the 60KW inverter is up to 367kWh. See picture
7 for power generation data monitoring.
PV inverters deliver electrical energy to the grid,
meanwhile the quality of the grid affects the inverter. In some metal
processing factories, there is high-power equipment such as travelling crane,
welding machines, gantry milling machines and electric arc furnaces, etc. During
switch on/off of the equipment, electric energy changes drastically, grid can’t
adjust in time, and the voltage changes between 320-480V in a very short time,
accompanied by a large number of harmonics and severe electromagnetic
The grid-tied inverter is a current source, due to
the impedance of the circuit, the BUS voltage of the inverter is usually
slightly higher than grid voltage. When large inductive equipment starts on the
load side, grid voltage is pulled to very low level, then the inverter output
current rises to a high level in a very short duration, the operating current
of the IGBT will also rise accordingly, which leads to a high risk of
over-current damage of the IGBT.
When the large inductive load stops, the grid
voltage will then suddenly rise, even exceed the BUS voltage of the inverter,
resulting in grid current feedback to inverter and risk of IGBT overvoltage
Electromagnetic interference will affect the IGBT
driver circuit of the inverter, and may cause the fault of IGBT switching
sequence and the pass-through in the bridge arm, resulting in a risk of
short-circuit damage to the IGBT.
Growatt R&D engineers have made many
innovations in the hardware and software design of the MAX 60-100K TL3-LV/MV
series inverters for harsh grid environments:
1) A dedicated high-speed CPLD for signal processing, coupled with
high-precision floating-point arithmetic and fast analysis algorithms, ensures
that the response speed of the inverter control is much greater than the speed
of the current and voltage changes on the grid side, the inverter has enough
time to handle the emergency.
2) Faster response measures are added to the IGBT driver active clamp
scheme, enabling the IGBT driver to operate as quickly as possible. When a
short circuit occurs, it gently turn off the IGBT to ensure that the current
ramp rate is within a certain range to avoid IGBT over-current.
3) Adopt multiple measures such as high-frequency non-inductive
capacitor and absorption loop to prevent IGBT overvoltage.
4) A reliable magnetic-coupled driver isolation solution ensures a very
strong anti-interference capability.
Operating in a harsh grid environment, the inverter
protects itself from off-grid as well as from damage by means of software and
hardware coordinated control, and the maximum power point can be tracked in a
few seconds when the grid voltage returns to normal. Inverter safety and power
generation are guaranteed at the same time.