How to Choose EV Motor Systems for Honda Acty? 144V 25KW Rated Power, Max 45KW PMSM Liquid-Cooled Motor – Technical Parameters Guide
When retrofitting or designing an EV powertrain for the Honda Acty with a 144V 25KW rated power (45KW peak) PMSM liquid-cooled motor, focusing on precise technical parameters ensures optimal performance, efficiency, and safety. Here’s a breakdown of key parameters to evaluate:
1. Voltage & Power Specifications The 144V nominal voltage must align with your battery pack’s output. Verify the motor’s voltage range (e.g., 120–168V) to tolerate battery voltage fluctuations during charge/discharge. For power, 25KW continuous power suits urban driving, but the 45KW peak power enables short bursts for acceleration or climbing. Confirm the peak power duration (e.g., 30–60 seconds) to avoid overheating—this is critical for the Acty’s compact frame, which limits heat dissipation.
2. Torque & Speed Characteristics PMSM motors excel at high torque at low speeds. For the Acty, target a continuous torque of 120–150 Nm and peak torque of 220–280 Nm. This provides strong low-speed pulling power for its light body (typically 900–1,100 kg). Check the base speed (where rated power is achieved, e.g., 1,800–2,200 RPM) and maximum speed (e.g., 6,000–8,000 RPM). A higher base speed reduces the need for a large gear reduction, saving space—key for the Acty’s tight engine bay. Also, review the torque-speed curve: flat torque at low RPMs improves drivability in city traffic.
3. Cooling System Parameters Liquid cooling uses a coolant loop (water-glycol mix) to maintain the motor’s temperature. Key parameters include:
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Coolant Flow Rate: Typically 5–10 L/min—ensure compatibility with your pump’s capacity.
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Temperature Limits: Motor windings should stay below 150°C; coolant inlet temperature should be 60–80°C. Exceeding this risks insulation degradation.
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Heat Dissipation: The system should dissipate 3–5 KW of heat (25KW × 12–20% efficiency loss). Match the radiator size to this, considering the Acty’s small front grille for airflow.
4. Efficiency & Losses High efficiency (≥92% at rated load) extends battery range. Review the efficiency map across torque-speed ranges—focus on urban driving zones (0–40 km/h). Lower copper losses (from winding resistance) and iron losses (from core material) boost efficiency. For a 25KW motor, aim for total losses <2 KW at rated power. This reduces cooling demands and energy waste.
5. Mechanical & Mounting Specs The motor must fit the Acty’s original engine mount points. Check:
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Shaft Dimensions: Diameter and length should match the transmission input shaft.
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Mounting Flange: Confirm bolt hole patterns (e.g., ISO 1081 standard) and flange size.
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Weight: Keep it under 40 kg to avoid overloading the front axle. PMSM motors are lighter than induction types, aiding this.
6. Control & Communication The motor needs a compatible inverter. Key parameters:
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Voltage/Current Rating: Inverter should handle 144V and 180–220A continuous current.
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Control Mode: Vector control is ideal for PMSM, enabling precise torque/speed regulation.
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Communication Protocol: Ensure CAN bus compatibility (e.g., CAN 2.0B) for integration with the Acty’s vehicle controller.
7. Protection & Safety
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IP Rating: IP67 or higher is ideal for dust/water resistance—critical for underhood use.
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Insulation Class: Class H (180°C) insulation tolerates high temperatures.
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Fault Protection: The system should include overcurrent, overvoltage, and overheat protection to prevent damage.
8. Compatibility with Acty’s Drivetrain The Acty’s transmission is designed for low-torque ICE engines. Verify the motor’s torque output doesn’t exceed the transmission’s rating (check service manuals). If needed, add a torque limiter. Also, confirm the motor’s rotational direction matches the original engine (typically clockwise from the front).
Final Steps After shortlisting motors, simulate performance using Acty-specific data (weight, drag coefficient). Test the system in a bench setup to validate cooling, efficiency, and control. Finally, ensure all parameters comply with local EV safety standards (e.g., UN R100). Balancing these technical specs ensures a reliable, efficient EV conversion for the Honda Acty.
