GW Instek RBS Series: Regenerative Bidirectional DC Source for EV and Power Testing

One Instrument That Both Supplies and Absorbs Power

The GW Instek RBS Series is a regenerative bidirectional DC source, a single 3U chassis that behaves as a programmable DC power supply and a programmable DC electronic load at the same time. The detail that sets it apart from a conventional supply-plus-load pairing is what happens to the energy it absorbs: instead of turning that energy into heat inside a resistor bank, the RBS converts it back to AC and returns it to the building’s electrical supply.

That single capability changes the economics of the test workloads expanding fastest in Indian power-electronics labs, EV battery validation, on-board-charger characterisation, bidirectional DC-DC converter testing, solar-inverter MPPT verification, and grid-tied energy-storage qualification.

The Model Lineup at a Glance

The RBS is built on one 3U / 19-inch platform and offered in three power classes and six voltage classes, twelve models in total. Current is bidirectional, so the same magnitude is available whether the instrument is sourcing or sinking.

Power class	Voltage classes	Peak current
5 kW	100 V · 500 V · 750 V	±170 A (RBS05K-100)
10 kW	100 V · 500 V · 750 V · 1000 V	±340 A (RBS10K-100)
15 kW	100 V · 500 V · 750 V · 1500 V · 2250 V	±510 A (RBS15K-100)

The single-unit ceiling is ±510 A on the 15 kW / 100 V model (RBS15K-100). Need more? Up to ten identical units run in master-slave parallel for 150 kW of system power, and 100 V models can be paired in series as long as the combined voltage stays within 300 V.

How the Regenerative Architecture Pays Off

In sink mode the RBS recovers absorbed energy to the grid at up to 93% efficiency. For a lab cycling battery packs or burning in converters around the clock, that has two compounding effects: the electricity meter runs far slower than it would with a dissipative load, and the air-conditioning no longer has to fight kilowatts of waste heat. The longer and higher-power the test, the larger the saving, which is why energy recovery is increasingly written into equipment-selection and ESG criteria rather than treated as a nice-to-have.

Bidirectional Operation in Practice

Because source and sink live in the same instrument and switch over in milliseconds with no dead band, a battery pack needs only one connection to be both charged and discharged, there is no rewiring between a separate supply and load. For DC-DC converter work, the bidirectional behaviour naturally exercises the forward and reverse power paths that automotive bidirectional converters are designed to handle.

Built-in Battery Simulation

The RBS carries eight fixed battery models plus one user-defined model: lithium manganate (LMO), lithium cobalt oxide (LCO), lithium iron phosphate (LFP), ternary lithium (NCM), lithium titanate (LTO), lead-acid (Pb), nickel-metal hydride (NiMH) and nickel-cadmium (NiCd). The emulation reproduces each chemistry’s voltage-current characteristic and state-of-charge behaviour, so a battery management system (BMS) can be qualified without a physical pack on the bench. When a real pack is connected, a dedicated charge/discharge mode runs full cycles with complete protection, and because the discharge energy is regenerated, round-the-clock cycle testing stays economical for the kind of EV battery validation Indian programmes require.

PV Simulation for Solar-Inverter Validation

On models rated 500 V and above, the RBS adds a built-in Solar Array Simulation (SAS) function with PV SAS, EN50530 and Sandia profiles. It drives both static and dynamic MPPT tests and reproduces awkward real-world irradiance, cloud shading and cloud movement, so an inverter’s maximum-power-point-tracking algorithm can be stress-tested indoors, independent of the weather. User-defined I-V curves cover the cases the standard profiles do not.

Energy Storage and DC-DC Converter Work

For grid-scale storage qualification, the RBS sources DC-bus voltage at utility-typical values and sinks the discharged energy with regeneration, making continuous cycling affordable where resistive loads would not be. For DC-DC converter validation, high-voltage-to-48 V, 48 V-to-12 V, and bidirectional traction-drive converters, the same source-and-sink combination handles forward and reverse power flow without a separate load instrument.

Automation: Sequence Programming

The list/sequence engine stores up to 50 sequences of 20 steps each. Every step independently sets voltage, current or power, operating mode, dwell time, loop count, ramp output and jump behaviour, enough structure to script automatic test and aging routines and let them run unattended. Control is over a 4.3-inch colour touch panel locally, and remotely through either the 4-in-1 interface card (USB, RS-232/RS-485, CAN, LAN) or the GPIB card, with GW Instek’s dedicated PC software on top.

Where the RBS Fits Among GW Instek Loads and Sources

The AEL-5000 Series is GW Instek’s programmable AC/DC electronic load with Turbo Mode and an AC Rectifier Load Mode, used for UPS, inverter and breaker testing, a dissipative, non-regenerative load. The PEL-5000G is a high-power DC electronic load with Turbo Mode for power-supply and battery-discharge testing. The RBS is the platform to reach for when the requirement is genuinely bidirectional, source and sink in one chassis, with grid energy recovery. For a side-by-side of regenerative versus dissipative testing, see Regenerative vs Traditional Electronic Loads, and for where each model fits, our RBS applications and model-selection guide.

Buying the RBS Series in India

GSAS Micro Systems is GW Instek’s authorized partner in India. We supply the full RBS Series with INR invoicing, model selection matched to your DUT’s voltage and current envelope, and after-sales calibration support from offices in Bengaluru, Hyderabad, Chennai, Pune, Mumbai and Delhi NCR, with service reach across Visakhapatnam.

Request a quote → · Book a demo → · See the RBS Series →