DC-DC Converter Testing

DC-DC Converter Testing

Manufacturer of automotive DC-DC converters slashes test time by 95 percent

The electrification of passenger cars and commercial vehicles has triggered a shift from traditional 12-volt platforms to high-voltage, high-power DC systems. Across a growing number of e-mobility applications, devices called DC-to-DC power converters are a crucial system component. In the powertrain of an electric vehicle (EV) or hybrid electric vehicle (HEV), these converters operate at power levels that range from 60 to 180 kW or higher. Elsewhere inside a vehicle, a growing number of “boost” (step-up) and “buck” (step-down) converters are also being used to power the latest advanced driver-assistance systems (ADAS) and a variety of safety, comfort, convenience, body, and chassis features. One of the world’s leading original equipment manufacturers (OEM) of DC-DC converters for EVs and HEVs faced a rapid increase in orders for its higher-power models. These included buck converters that step down high voltages (e.g., 200-300 V) to 48 V for EV and HEV powertrains. Because reliability is an important differentiator for all EV/HEV components, the company decided to replace a mostly manual testing process with a more automated solution that would save time and enhance product quality.

The Challenge: Overhauling an Outdated Test Process

Among the manufacturers that produce multiple lines of DC-DC converters— 48, 300 or 1,000 V—all face the challenge of testing a wider range of devices while meeting increasingly difficult goals for cost-of-test and time-to-market. In this case, the challenges were especially difficult because the OEM’s manufacturing-test team was relying on technicians to manually characterize converters on the production line. This process had two critical bottlenecks. First, their existing power analyzer was capable of testing only one converter at a time. Second, data logging was especially slow and tedious because reports were being entered manually, and this increased the likelihood of misleading results caused by human error. The problem became more severe as the OEM experienced rapid order growth and escalating demand for exceptional product reliability. This put the manufacturing team under tremendous pressure to test more parameters on more units in less time. Hoping to find a solution, they decided to explore new test strategies that would shorten test time and reduce the escalating cost of test.

The Solution: Redefining Converter Testing

During its initial meeting with Keysight, the OEM outlined two essential needs. First and foremost, they wanted a robust and future-proof system that would help them test a variety of high-powered products quickly and cost-effectively. In addition, they wanted an architecture that would ensure the safety of their engineers and technicians when working with high voltages and power levels. After assessing the overall situation and the crucial needs, Keysight’s engineers proposed a new process that would save time and reduce costs by automating testing and data logging. The solution addressed five key areas: measuring insulation resistance, simulating high-power DC voltages, measuring input voltages, measuring multiple output voltages, and sinking current measurements.

The system included four primary elements:

• Keysight B2985A electrometer/highresistance meter 
• Keysight N8900 autoranging DC power supply
• Keysight 34980A multifunction switch/ measure unit (SMU)
• Keysight N3300 Series DC electronic loads