High Voltage Grid Simulator Adds PV Inverter’s HVRT Test Function

As photovoltaic industry policies continue its growing support for distributed solar power systems, commercial power generation equipment demands for 20kVA-100kVA inverters increase as well. With the development of grid-connected high-voltage 600Vac-800Vac (VLL) systems to reduce cost and increase power generation efficiency, an important challenge to manufacturers is the inverter’s stability in high-voltage grid connections. The newest high-voltage 1385Vac (VLL)/120kVA regenerative grid simulator released by Chroma meets the specifications for inverter quality verification and grid performance tests, such as LVRT, HVRT, harmonics, waveform distortion, 3-phase unbalance, voltage dips, short interruptions, and voltage change immunity tests.

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The latest UL1741 SA specification for inverter design must be able to run under HVRT test without off-line operation. In addition, it must have the capability to continuously adjust the power and infuse reactive current into the power system during high voltage ride through. So, when the inverter is designed for a normal rated voltage of 690Vac (VLL), it must be tested for rated grid voltage (over 897VLL) which is raised 1.3, 1.2, or 1.1 times respectively as it has to run uninterruptedly at dozens of test points during voltage rise and recovery. Moreover, it has to respond normally and issue a proportioned capacitive reactive current according to the standard during HVRT, which can effectively stabilized the grid voltage and ensure the demand for the quality of electricity.

Chroma’s high-voltage power grid simulator can output voltage up to 1385VLL (800VLN) without using a step up transformer. Besides up to 1.5V/us output voltage transient capability, it has flexible, cost-effective and space-saving features. For example, when testing an inverter below 50kVA, it can be used as two 60kVA power grid simulators; and if high power and high voltage 60-100kVA inverters are required for testing, two 60kVA power grid simulators can be connected in series for up to 1385VLL (800VLN).

For more information about Chroma 61800 features and specifications, please visit Chroma’s website: Chroma 61800 Series Regenerative Grid Simulator

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New Regenerative AC Load Function – Further Extend the Grid Simulator Capability for Micro-grid Test Application

The Chroma 61800 Series high power regenerative grid simulator capable of delivering output power up to 300kVA has been widely used for testing PV inverters, power conditioning systems (PCS) and EVSE charging stations. Lately, more and more engineers are studying the applications of micro-grids and energy storage systems. The 61800 Series not only can simulate the voltage and frequency test requirements for different regions of world, it is also capable of simulating voltage transient and abnormal conditions with synthesis of harmonic / inter-harmonic components as well. Its full four quadrants operation capability and regenerative function used to feed the energy back to the grid are the most favored by users.

Aside from the aforementioned capabilities to simulate the AC voltage test conditions, the capabilities of simulating various load conditions in order to cope with the diversified and dynamic nature of the system are also required for the micro-grid testing. It is very rare in the market to have test equipment with both AC source and AC load functions as a single unit.

Traditional AC electronic load designs mainly consist of passive and switch devices. These electronics loads can only operate in the 1st quadrant (both voltage/current in the positive region) and 3rd quadrant (both voltage/current in the negative region). The functionalities for the traditional AC electronic load are mainly limited to CR mode and rectified mode due to the design’s nature. Unlike the traditional electronics load, Chroma 61800 Series with full four quadrants and a regenerative design has further extended its test application capabilities by including the regenerative AC load function as an option with its maximum loading capability equivalent to the maximum output power rating of the unit. For instance, with the AC load option installed, the 61800 Series is capable of providing up to 180kW loading capability.

The phase lead/lag mode with phase angle setting ranging from 90 degree ~ -90 degree will simulate the corresponding voltage and current condition under an inductive or capacitive type load (see below waveforms). When the phase angle setting is in the range of 90.1 degree ~ 180 degree (-90 degree ~ -180 degree), the 61800 will become a current source, similar to a programmable inverter which is applicable for micro-grid related testing.

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The Chroma 61800 Series regenerative AC load function is applicable for AC power supplies, UPS, PCS and EVSE charging station (V2L/V2H) test applications. It can simulate the effects of different loading conditions based on various home appliances, or test the PV inverter’s power quality correction functionality by deliberately setting the AC load in various reactive load conditions. The regenerative AC load is applicable for simulating the various power flow conditions related to micro-grid application for research in smart management or for balancing supply and demand loads.

Chroma uses the DSP digital control method to add the optional AC load function to the 61800 Series regenerative grid simulator. The AC load function further diversified the 61800 Series test applications ranging from academic, R&D design verification, and quality assurance to mass production.

For more information on the Chroma 61800 features and specifications, please visit Chroma’s website:   Regenerative Grid Simulator Model 61800 Series

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A Productive Utility for New Energy Vehicle LV123 Standards Tests Chroma High Voltage DC Power Supply Test Software

Complying with global energy conservation trends and policies driven by international governments, many automakers have released technical development standards for next generation vehicles, which define various electric vehicle tests for hybrid, plug-in hybrid and fuel cell vehicles. Chroma has integrated these regulatory requirements aiming to provide users with specialized and convenient test programs making Chroma a productive partner for testing new energy vehicles.

The test requirements of LV123 are defined by major European carmakers to test the electrical characteristics and safety of high-voltage components in road vehicles, such as HV battery system, inverter, electrical air conditioning compressor, electrical transmission oil pump, DC/DC converter HV/LV and On-board charger, etc. This standard defines the state and operating capability of each voltage range.

The LV123 standard regulates different states for voltage range from 0V to 800V, as shown in the table below, and demands rapid voltage slew rate change. Chroma’s 62150H-1000 DC power supply supports 0-1000V voltage output with up to 40V/ms slew rate control and can meet the LV123 basic electrical characteristics requirements through the test items listed below providing the best solution for testing new energy vehicles.

HV voltage ranges Unit HV_1 HV_2a HV_2b HV_3
Overvoltage at load dump V pk 220 410 500 800
Upper HV circuit limit voltage V pk 220 410 500 800
Maximum operating voltage V d.c. 200 360 470 770
Upper limited operating capability >V d.c. > 190 – 220 > 340 – 460 > 450 – 470 > 750 – 770
Unlimited operating capability V d.c. 90 – 190 170 – 340 250 – 450 520 – 750
Lower limited operating capability V d.c. 80 -< 90 160 -< 170 200 -< 250 450 -< 520
Highly limited operating capability V d.c. 60 -< 80 120 -< 160 200 -< 250
Undervoltage V d.c. 0 -< 60 0 -< 120 0 -< 150 0 -< 450

The following test items are provided according to the LV123 standard.

  1. Range of unlimited operating capability
  2. Range of upper limited operating capability
  3. Range of lower limited operating capability
  4. Range of highly limited operating capability

Chroma integrated the voltage range operating capability of LV123 into the 62000H Series DC power supplies and developed graphical test software based on the regulatory criteria so that the user can perform tests on the UUT with only one key. This not only saves time in the development schedule but also facilitates testing automotive electronics for their long-term performance and stability.

Range of unlimited operating capability
Range of unlimited operating capability

Range of upper limited operating capability
Range of upper limited operating capability

Range of lower limited operating capability
Range of lower limited operating capability

Range of highly limited operating capability
Range of highly limited operating capability

To learn more about the computer graphical user interface:

<Introduction to Softpanel for Model 62000P&H Series>
<Programmable DC Power Supply Model 62000H Series>

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Fast Transients, Low Noise in Chroma’s New Benchtop DC Power Supplies

Chroma’s newly launched 62000L Series programmable DC power supplies provide low ripple, low noise linear performance and a fast transient response in a lightweight, compact, and cost effective package.

As Chroma’s next generation of power supplies, the 62000L Series delivers pure and stable DC power as well as built-in features designed to meet the stringent requirements of next generation power electronics including automotive power electronics MCU/ECU, communication electronic parts, and semiconductor IC drivers.

Comparison of traditional models

Auto-ranging allows for freely adjusting the voltage and current. This feature eliminates the need to manually select the optimum range allowing all of the power to be available across all of the voltage and current settings.

Fast transient response makes the output voltage that changed due to load characteristics return to a stable supply of power in microsecond response speed. Take the 62010L-36-7 model for example, when the output current changes from half load to full load at the speed of 1A/μs, the voltage change of the actual output can return to 15mV within 30μs.

Low noise input power with pure quality protects the precision load or UUT from the interference of heavy noise. For example, the 62010L-36-7 output voltage noise is lower than 2mVp-p (20~20MHz) under the maximum rated current and maximum output power.

The auto sequencing programming function built into the 62000L Series allows the user to define and edit the output waveforms with 8 steps per cycle.

Conventional linear power supplies are cumbersome due to the frequency design and require more space for ventilation. Chroma simplified the design of the hardware architecture resulting in a better handling compact, lightweight design which is safer to stack.

The brand new 62000L Series programmable DC power supplies features an affordable price, high quality output specifications, practical functions, and standard USB and GPIB communication interfaces making this an excellent choice for testing small power and precision products.

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Chroma ATE Inc.