Design of a Portable Pulsed Power System for Needle-Free Jet Injection

Abstract

Needle-free jet injection (NFJI) is a drug delivery technique that requires the application of a brief (10 ms to 100 ms) pulse of high force to pressurize a liquid drug and force it through the skin. To provide control over this force using an electric motor, high drive power is needed from a compact system. This work outlines the design process of an untethered power and motor drive system that is estimated to weigh approximately 2.5 kg, capable of supplying 1.6 kW at 210 V peak-peak. The device is used to drive a linear synchronous motor to deliver up to 31 large volume (1 mL) needle-free jet injections (NFJI) within a single recharge. The system architecture, gathering of detailed functional requirements, selection of energy storage, and the studies of power electronics and motor drive via system simulation are discussed. Inspired by electric vehicles' battery boosted motor drives and cascaded interleaved boost converters for high step-up conversion ratio, the proposed design employs a battery-powered boost converter which then energize a 3-level inverter with the peak to peak voltage of 210 V. The design utilizes the latest gallium nitride (GaN) transistors as well as the latest lithium-ion capacitors (LIC) for energy storage. The power electronic topology introduced in this work is also adaptable for other high energy pulsed applications such as plasma generation, or MRI gradient coils.

Application of Linear Permanent Magnet Flux-Switching Motors to Needle-free Jet Injection

“…• The motor length L S should not exceed 16 cm and mass M should fall in the range or 300 g to 400 g but not significantly more, • The average power consumption P E should be less than 1.6 kW, dictated by the power limit imposed by our battery powered control system in [19]. • The combination of force produced F and stroke length L stroke must allow for 1 mL jet injection through a 200 µm nozzle diameter at an average jet speed of v = 120 m/s, and peak jet speed of v peak = 140 m/s.…”