Precisely
on target.

Lee J motion designs and builds motor drives, power converters and control panels, and writes the control algorithms and firmware that run inside them, so your equipment stops exactly where you command it.

See what we build

Position control simulation

Target
135.0°
Actual
135.0°
Error
0.0°
Click the dial to set a new target angle. The position controller brings the needle onto it, and the plot below draws the step response.

We build the whole drive chain

From the control panel that issues the command, through the power converter, to the motor that moves, plus the cables that connect them.

  1. Control panels and controllers

    Motion controllers, electrical control panels, and control units for operation and testing

    Registered asManufacture of switchboards and electric automatic control panels

  2. Power converters

    IGBT inverters and converters, gate drives, current and voltage sensing, and protection circuits

    Registered asManufacture of other electric converters

  3. Motors and drive units

    PMSM servo drive units combined with high-resolution encoders for position control

    Registered asManufacture of electric motors and generators

Cables and harnesses

Power and signal cables and connector harnesses that tie the three together.

Registered asManufacture of other insulated wires and cables

From command to shaft, the whole control loop

We design every stage a position command passes through before it becomes motion at the motor shaft.

Position control loop block diagramThe target position r passes through the position and speed controller (1), the FOC current controller (2) and the IGBT inverter (3) to drive the PMSM. Position sensing/tracking (4) gives the position, the state estimator (5, Kalman filter) refines it and feeds it back, and phase current returns to the inner loop. Blocks 1, 2 and 5 run in the TI C2000 DSP firmware (6). 6 DSP firmware (TI C2000) r target + − e Position andspeed control i* Current control(FOC) PWM Inverter(IGBT) uvw Motor(PMSM) y actual position phase current Position sensing/tracking position State estimator(Kalman filter) estimate 1 2 3 4 5 Position control loop block diagramThe target position r passes through the position and speed controller (1), the FOC current controller (2) and the IGBT inverter (3) to drive the PMSM. Position sensing/tracking (4) gives the position, the state estimator (5, Kalman filter) refines it and feeds it back, and phase current returns to the inner loop. Blocks 1, 2 and 5 run in the TI C2000 DSP firmware (6). 6 DSP firmware r target + − e Position andspeed control i* Current control(FOC) PWM Inverter(IGBT) uvw Motor(PMSM) y actual position phase current Position sensing/tracking position State estimator(Kalman filter) estimate 1 2 3 4 5
Numbers in the drawing match the items below.

  1. Position and speed control

    Cascaded position and speed loops, tuned to follow the target through load changes and disturbances.

  2. FOC current control

    Field-oriented control of PMSMs to command torque directly. The current-loop bandwidth sets the response of every loop above it.

  3. Inverter and power stage

    IGBT gate drive, current and voltage sensing, over-current and thermal protection, and the heat-sink design.

  4. Position sensing/tracking

    Resolvers and digital position sensors such as BiSS-C, and fusion of several sensor signals for higher absolute accuracy.

  5. State estimation

    Kalman filters that estimate position, speed and acceleration while reducing the effect of sensor noise and delay.

  6. Embedded firmware

    Real-time control cycles, communication and diagnostics on TI C2000 dual-core DSPs.

All hardware is designed with EMC, grounding and shielding, and military-standard (MIL-STD) requirements in mind.

From requirements to production

One team carries the work from start to finish, so nothing gets lost between stages.

  1. Requirements

    Agree on operating conditions, interfaces and test criteria.

  2. Design

    Design the control algorithm, circuits and firmware structure, and check them in simulation.

  3. Prototype

    Build the boards and harnesses, load the firmware and run it against a real load.

  4. Test and verification

    Prepare performance, environmental and EMC tests and document the results.

  5. Production and support

    Hand over production documentation and solve field issues together.

About us

Lee J motion opened in Changwon, Korea in October 2026 as a motion-control company. Control algorithms, power electronics and embedded firmware are handled by one team, so every change is designed with its effect on the rest of the system in view.