PV Inverter Test – Grid-tied, Off-grid, and Hybrid

A photovoltaic or PV inverter, converts the direct current (DC) output of a solar cell or array into an alternating current (AC) that can be fed directly into the electrical grid (Grid Tie), used by a local electrical grid (Off-Grid), or both (Hybrid Inverters). The PV Inverter is a key component in a photovoltaic system, allowing the use of household and commercial AC powered devices. Solar PV inverters have special functions adapted for use with photovoltaic arrays, including maximum power point tracking (MPPT) and anti-islanding protection.

Our test instrumentation provides means to further the development, reliability, and validation of grid-tied, off-grid, and hybrid solar PV inverters that will eventually be used in commercial and household applications for years to come. We do this by integrating features into our testers that, for example, allow performance testing of inverter behavior during voltage and frequency fluctuations found on the grid. And we can do this either by standalone instrumentation or integrated into an automated test system.

PV inverter test block diagram

The block diagram shown represents a basic set up for either grid-tied or off-grid PV inverter test.

Grid Tie PV Inverters

An on-grid or grid-connected photovoltaic power system is tied to the local utility mains or grid. They are typically used for residential or commercial applications where any unused power generated is sent to the utility grid where it can be stored and used later. Grid Tie PV Inverters (GTI) are equipped with micro-controllers that synchronizes generated power to the grid. The grid-connecter inverter converts the DC energy collected by the photovoltaic solar panels to AC power which is then either consumed or transferred to the local utility grid. Grid connected PV systems do not require a battery system since the grid provides the on-demand energy.

Off-Grid PV Inverters

An off-grid photovoltaic system allows consumers to have an energy system independent of the utility infrastructure. Power generated by the PV system is either consumed or stored in an on-site battery for later use rather than the grid. Off-Grid Inverters are not designed to sync the generated power to the grid.

Hybrid PV Inverters

Hybrid Off-Grid Inverters (HOG) also known as Grid Tie Inverters with battery backup are an innovative combination of Grid Tie and Off-Grid Inverters.

Maximum Power Point Tracking

Maximum Power Point Tracking (MPPT) is a method used to optimize the amount of energy harvested through a photovoltaic solar system (or other variable sources). A photovoltaic system’s efficiency depends on the amount of power or sunlight collected and transferred to the solar cells. The MPPT is a process that maximizes this energy transfer by finding the point where the solar cells are collecting the most energy thus optimizing the function and efficiency of a photovoltaic system. Moreover, the MPPT filters and distinguishes the most usable power for specific devices or systems by determining the most proper resistance rather than random loads being fed to arbitrary photovoltaic cells. MPPT devices are generally integrated into electric power converter systems.

Anti-Islanding Protection

Anti-islanding protection is a way for the inverter to disconnect itself when it identifies a problem with the power grid so there is no unnecessary power transfer. This safety feature is typically integrated into distributed generators so that all grids can detect islanding (islanding – continually feeding the circuit with power even after shutdown).

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PV Inverter Test

Solar Array Simulation – Steady, Repetitive Control

A practical solar array can be very large and is influenced by various weather conditions like irradiation, temperature, rain, dirt, and shade which affect the I-V curve output. Unless you have a lot of time and real estate to duplicate these characteristics in the lab, a solar array simulator provides the best solution for testing PV Inverters. The advantage a solar array simulator provides is steady, repetitive control conditions that are required for PV Inverter design as well as for verification testing.


Solar Array Simulator

Solar Array Simulators
Solar Array Simulator DC Power Supply – 62000H-S
2kW – 15kW, up to 1.5MW
0-600V, 1000V

Programmable Solar Array Simulator that provides simulation of Voc (open circuit voltage) up to 1000V and Isc (short circuit current) up to 25A. The Solar Array Simulator is highly stable and has a fast transient response, which are both needed for MPPT performance evaluation on PV inverter devices.

Reasons to choose our Solar Array Simulator:

  • Maximum power point tracking circuit and algorithm of the PV inverter
  • High/low limit of operating input voltage allowed for the PV inverter
  • High/low limit of operating input voltage allowed for the inverter’s maximum power point
  • Static maximum power point tracking efficiency of the PV inverter
  • Overall efficiency & conversion efficiency of PV inverter. (Requires a power meter)
  • Maximum power point tracking performance of the inverter for dynamic curves. (EN50530, Sandia, CGC/GF004 standard)
  • Maximum power point tracking performance of the inverter under various time periods spanning from morning to nightfall
  • Maximum power point tracking mechanism of the inverter for the I-V curve when the solar array is shaded by clouds, trees, dirt, rain and snow
  • Simulating the I-V curve under environmental temperatures for inverter burn-in testing


Grid Simulation simulator

Grid Simulation

The world’s adoption of clean renewable energy has created a demand for PV inverters, wind energy systems, and other distributed energy resources. This demand has triggered rigorous regulation testing to standards such as IEEE 1547 / IEC 61000-3-15 / IEC 62116 that ensure proper and safe operation of on-grid products. Increasingly critical to manufacturers is the test equipment that provide the means to prove compliance and relieve product liability concerns. Chroma Regenerative Grid Simulators fulfill these test requirements by providing full 4 quadrant, regenerative, grid simulation with advanced features for compliance, safety and product verification testing.


Grid Simulators
61800 Regenerative Grid Simulators
30kVA – 60kVA, up to 300kVA
330V L-N

Chroma 61800 Regenerative Grid Simulators have been designed to ensure proper and safe operation of on-grid products by providing a full 4 quadrant, fully regenerative, grid simulator with advanced features for compliance, safety and product verification testing.

Reasons to choose our Grid Simulator:

  • Chroma’s standard output voltage of 330V L-N as compared to 300V L-N found in the market
    • 0-300V L-N range does not sufficiently cover a +10% variation for 480V L-L applications
  • 0-400V L-N / 0-692V L-L option that does not require a transformer
  • Maximum power delivered down to 200VAC L-N which provides a wider output power range
  • Better front panel display with a real time waveform viewer
  • Parallel modular design allowing for field expansion up to 300kVA


PV_inverter_test_software

PV Inverter Test Instruments

Our test instrumentation provides means to further the development, reliability, and/or validation of various solar PV inverters that will eventually be used in commercial and household applications for year to come. We do this by integrating features into our testers that, for example, allow performance testing of inverter behavior during voltage and frequency fluctuations found on the grid. And we can do this either by standalone instrumentation or integrated into an automated test system.


AUTOMATED TEST SOLUTIONS

PV Inverter Automated Test System

PV Inverter ATS
8000 Automated Test System

To meet PV inverter test requirements, Chroma 8000 Automated Test System has built in 56 ready-made test items. Users may create new test items based on new test requirements using the test item editing function, which gives users the capability to expand the test items without limits.



DC POWER SUPPLIES

Solar Array Simulator

Solar Array Simulators
Solar Array Simulating DC Supply – 62000H-S
2kW – 15kW, up to 1.5MW
0-600V, 1000V

Programmable Solar Array Simulator that provides simulation of Voc (open circuit voltage) up to 1000V and Isc (short circuit current) up to 25A. The Solar Array Simulator is highly stable and has a fast transient response, which are both needed for MPPT performance evaluation on PV inverter devices.

DC power supply

Programmable High Power DC Supply
62000H
5kW – 15kW, up to 150kW
0-600V, 1000V

Input DC voltage test.

Programmable DC Power
62000P
600W – 5kW

Input DC voltage test.

AC POWER SOURCES

Programmable AC Power
61500
500VA – 9KVA

Simulate grid power: Voltage/Frequency/Transient/Wave

VIEW

High Power AC Source
61510
12KVA – 90KVA

Simulate grid power: Voltage/Frequency/Transient/Wave

Regenerative Grid Simulator
61800
30kVA – 60kVA, up to 300kVA
330V L-N

Designed to ensure proper and safe operation of on-grid products. Provides full 4 quadrant, regenerative, grid simulation with advanced features ideal for PV Inverter testing.

AC ELECTRONIC LOADS
POWER METERS

AC electronic load

AC Electronic Loads
63800
1.8KW – 4.5KW

Used to sink current directly for testing off-grid PV inverters. AC Sources provide a voltage level as the reference for the PV inverter output. If the AC source cannot sink current, an external resistor is necessary for load simulation.

  • Dynamic loading: up to 20KHz
  • Measurement: V, I, P, R
  • Voltage & Current monitor

power meter - single channel

Single Channel Power Meter
66205
15Vrms ~ 600Vrms
5mArms ~ 30Arms

Used to measure PV inverter output parameters, such as V, I, P, PF, current harmonics and THD.

  • The 66205 provides better measurement accuracy across the board
  • Complies with IEC 62301/Energy Star power measurement frequency bandwidth > 3kHz (Filter ON) requirement
  • Cycle based measurement, 1.5sec smoothing filter, grouping settings are preferable for harmonics measurement requirement in according to IEC 61000-4-7
  • Harmonic and total harmonics distortion functions are standard, not extra cost options
  • The 66205 provides more standard interface features

66204_power_meter

Multi-Channel Power Meters
66203, 66204
15Vrms ~ 600Vrms
5mArms ~ 20Arms

Multi-Channel Digital Power Meters designed for both single-phase and multiple phase measurements of AC power signals and related parameters common to most PV Inverters. Used to measure PV inverter output parameters, such as V, I, P, PF, current harmonics and THD.

  • Support external shunt and CT for higher current measurement application
  • Complies with IEC 62301/Energy Star power requirements
  • Support different wiring configuration power measurement (1P2W/1P3W/3P3W/3P4W)
  • Voltage/ Current harmonics measurement up to 50 orders

Electrical Safety Testing

Chroma offers several solutions for the development of safe PV Inverters. Our electrical safety testers support AC/DC hipot, leakage current (LC), insulation resistance (IR), and ground continuity (GC) at very high speed and accuracy to ensure the quality and safety of commercial and consumer inverters before they reach the market.

hipot tester - 19070 - chroma

19070 Sentry Hipot Tester
Hipot 5kVac | 6kVdc
AC only or AC | DC | IR

A compact, low cost hipot tester. Provides AC hipot testing only or AC and DC hipot, 1kV insulation resistance.

19050 Guardian Hipot Tester
Hipot 5kVac | 6kVdc
AC | DC | IR

The Guardian 19052 is capable of AC/DC/IR Hipot testing and insulation resistance (IR) measurements. The Guardian 19053 combines both AC and DC Hipot tests and IR measurements with 8HV scan channel capabilities.

Hipot tester analyzer

19032 Guardian Electrical Safety Analyzer
Hipot 5kVac | 6kVdc
AC/DC/IR/GB/LC/Dynamic Function

The 19032 series combines Hipot, Insulation Resistance (IR), Ground Bond (GB), Leakage Current (LC)/AC LC/DC LC and Dynamic Function Tests. Space savings can be up to 50% of production line space, by eliminating multiple safety test instruments. The 19032 increases  efficiency of electrical safety testing during manufacturing and reduces associated labor costs.

Ground bond tester - chroma

19572 Guardian Ground Bond Tester
AC output: 45A

An instrument dedicated to measuring grounding resistance within the range of 0.1~510mΩ. Supplies highly reliable and stable test results with a built-in resistance compensate function. Its compact form factor and easy to operate features make it ideal for testing in a production line.


battery simulator

Battery Simulation

Battery simulation software for testing battery connected devices in all applications to confirm if the device under test in performing as intended. Integrated with our 17020, 17030, and 17040 regenerative battery testers, battery state is simulated if the battery is not available for testing and eliminates waiting for the charge/discharge of an actual battery. Real time test results include voltage, current, power, SOC%, charge/discharge state and capacity.

Battery simulation software

Multi-channel Battery Pack Simulator
Battery Simulation Software
17020 | 17030 | 17040

Test: Battery connected devices including PV Inverters

regenerative battery tester

See all Battery Test Solutions
17020 | 17030 | 17040