Inverter type

String Inverter

A PV inverter that connects one or more PV strings, usually in the power range of 3kW to 150kW.

Microinverter

Microinverters are small PV inverters that connect one or more PV modules, typically in the power range of 0.5 to 3kW.

MLPE (Module-Level Power Electronics)

Module-level power management equipment including power optimisers and microinverters.

Central InverterHigh-power inverters for large-scale PV power plants, with a higher number of connected strings, usually in the range of 250kW to 1,000kW.

On-grid Inverter

A PV inverter that feeds PV energy back into the grid.

Off-grid Inverter

An inverter system that operates independently of the grid, usually in conjunction with a battery storage system Hybrid Inverter An inverter that manages both PV input and battery storage at the same time.

Bi-directional Inverter

Bi-directional inverters are inverters that can convert AC and DC currents in both directions, often used in energy storage systems, and can be charged and discharged, another term for hybrid inverters.

Transformerless Inverter

Transformerless Inverter/High Frequency Inverter is an inverter that does not use an industrial frequency transformer and has a high efficiency, also known as a high-frequency inverter, a parameter that is commonly used in Inverter Topology.

Utility-frequency Inverter

An inverter that uses an industrial frequency transformer, has a better stability, but not as efficient as a high-frequency inverter, and is now mainly used in scenarios where stability is required to be relatively high (precision instruments).

Inverter Functions and Characteristics

MPPT (Maximum Power Point Tracking)

One of the most critical functions of a PV inverter to maximise the output of a PV system.

Anti-islanding Protection

A safety feature that automatically stops power output to the grid in the event of a grid power failure.

LVRT (Low Voltage Ride Through)

The ability of an inverter to remain connected to the grid during short-term drops in grid voltage.

HVRT (High Voltage Ride Through)

The ability of a high voltage ride through inverter to remain connected to the grid during short-term increases in grid voltage.

FRT (Fault Ride Through)

The ability of a power plant to remain in operation during a grid fault.

FFR (Fast Frequency Response)

The ability to quickly adjust output to support grid frequency stability.

FRT (Fault Ride Through)

Fault Ride Through (FRT) The ability of a power plant to maintain operation during a grid fault.

LFRT (Low Frequency Ride Through)

The ability of a generating plant to remain in operation when the grid frequency is reduced.

HFRT (High Frequency Ride Through)

The ability of a generating plant to remain in operation when the grid frequency increases.

APC (Active Power Control)

The ability of active power control to regulate the active output of a generating plant.

RPC (Reactive Power Control)

The ability to regulate the reactive power output of a generating plant

UPS (Uninterruptible Power Supply)

The function of an uninterruptible power supply to provide a continuous supply of power in the event of a grid failure.

Self-consumption

A self-consumption system that gives priority to locally generated electricity, reducing dependence on external power sources.

Islanding Mode

Islanding Mode is a mode of operation in which an inverter maintains local power supply in the absence of an external power grid.

Electrical Parameters

Max. PV Input Voltage

The highest PV input voltage that the inverter can withstand.

MPP Voltage Range

The range of input voltages over which the inverter can perform MPPT.

Number of MPP Trackers

Number of independent MPPT inputs to the inverter

Max. PV Input Current

Maximum PV input current that the inverter can handle

Max. PV Short Circuit Current

Max. input short circuit current the inverter can handle

Max. PV Open Circuit Voltage

The maximum PV open circuit voltage that the inverter can handle.

Nominal Frequency

The standard operating frequency of the inverter output, usually 50Hz or 60Hz.

Nominal Power

The maximum continuous power output of the inverter under standard test conditions.

Peak Power

The maximum instantaneous output power of a peak power inverter.

Nominal Apparent Power

The rated output capacity of the inverter in kVA or MVA.

Nominal AC Output Voltage

The standard output voltage of the inverter.

Iac_nom (Nominal AC Output Current)

Rated AC Output Current Standard output current of the inverter at rated power.

Max. AC Output Current

Maximum AC current that the inverter can output

AC Voltage Range

The range of grid voltage at which the inverter can operate normally.

DC/AC Ratio

The ratio of the PV array capacity to the rated capacity of the inverter.

Efficiency and power quality 

η max (Maximum Efficiency)

Maximum efficiency of the inverter under optimal operating conditions

η euro (European Efficiency)

Weighted average efficiency considering different load conditions.

CEC (California Energy Commission)

Efficiency California Energy Commission efficiency is similar to European efficiency, but with a different weighting, which is more applicable to the US market.

RTE (Round-Trip Efficiency)

The overall efficiency of the charge/discharge cycle of an energy storage system.

PQ (Power Quality)

The quality of the power output from an inverter, including harmonics, frequency stability, etc.

PF (Power Factor)

power factor inverter output active power and apparent power ratio

Power Factor Range

The adjustable power factor range of an inverter.

THD (Total Harmonic Distortion)

An important indicator of the quality of power output from an inverter.

Standby Consumption

The energy consumption of an inverter when it is not in operation.

Waveform

A graphical representation that describes the variation of AC voltage or current over time Pure Sine Wave

Ideal AC waveform, free of harmonic distortion, is the output target of high quality inverters Power Density

Power Density is the power output per unit volume or weight of the inverter, usually expressed in W/kg or W/L.

Other Technical Parameters

IP (Ingress Protection)

Protection Rating is an international standard that indicates the inverter’s ability to withstand dust and water.

Ambient Temperature Range

The ambient temperature range in which the inverter can operate normally.

Noise Level

The intensity of sound produced by the inverter during operation, usually expressed in decibels (dB).

EMI (Electromagnetic Interference)

Electromagnetic Interference (EMI) is the electromagnetic interference generated by equipment that may affect other equipment.

MTBF (Mean Time Between Failures)

An important indicator of inverter reliability

Cooling Method

The method of cooling and temperature control of an inverter, which affects its performance and lifetime.

Rated Altitude

The maximum altitude at which an inverter can operate normally, usually measured in metres.

Altitude Derating

As the altitude increases, the output power of the inverter is automatically reduced to adapt to the thin air environment.

Power Derating

A mechanism that automatically reduces the output power of an inverter to protect itself from high temperatures or other unfavourable conditions.

Weight

The physical weight of the inverter, which affects installation and transport.

Dimensions

The physical size of the inverter, usually expressed as length x width x height.

Components and accessories

IGBT (Insulated Gate Bipolar Transistor)

The main power switching element in an inverter.

MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor)

Metal-Oxide-Semiconductor Field-Effect Transistors

Commonly used voltage-controlled semiconductor switches

DSP (Digital Signal Processor)

The core processing unit responsible for complex calculations and control.

MCU (Microcontroller Unit)

Microcontroller to control the functions of the inverter integrated circuits

PCB (Printed Circuit Board)

Printed circuit board integrated various electronic components of the substrate

EMI (Electromagnetic Interference) Filter

A device that reduces the electromagnetic interference generated by an inverter.

DC Link Capacitor

A key component for stabilising the DC bus voltage.

Heat Sink A device that dissipates heat generated by inverter operation.

SPD (Surge Protection Device)

DC Surge Protection Device protects the inverter from lightning strikes and surges on the DC side.

GFDI (Ground Fault Detector Interrupter)

A device that detects and protects the system from ground faults.

AFCI (Arc Fault Circuit Interrupter)

Arc Fault Circuit Interrupter detects and interrupts arc faults.

RCD (Residual Current Device)

Residual current protection is a safety device that detects leakage and quickly cuts off the power supply.

Varistor (Voltage Sensitive Resistor)

A component that protects circuits from transient overvoltages.

TVS (Transient Voltage Suppressor)

Transient Voltage Suppressors are semiconductor devices used to protect circuits from transient high voltage.

DC Fuse

A safety device to protect inverters from overcurrent damage.

Relay

Electronic switches for controlling high-current circuits.

Ferrite Core

Magnetic components used to suppress high frequency electromagnetic interference

Hall Sensor

Magnetic induction device for contactless measurement of electric current

CT (Current Transformer)

Inductive transducer for measuring current, often used to protect against reverse current.