PARK Cheonsu – 道木研究室

PARK Cheonsu


研究テーマ / Research topic

Single Inverter Dual Motor Control

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Single Inverter Dual synchronous Motors System

Typically, one inverter drives a synchronous motor. However, in a system where two motors are driven at the same speed, two motors can be driven by one inverter. This system is mainly used in asynchronous motor control. In a synchronous motor system, there is a problem of unstable system due to load difference between two motors. Research is underway to solve these problems.

These systems can be applied to electric railways, 2fan system and conveyor belt systems, etc.

The advantages of this system are that it can reduce costs by reducing the number of power components and reduce the size of the driver. In particular, it is advantageous for cost to use one power component with twice the capacity of two power components in low power systems.
* Constraints : The speed of 2 motors is always the same.


Research Background and Theme 1:
Improving stability in low-speed areas

The problem with this system is that the system resonates due to disturbance such as load unbalance. Some researches have been carried out to solve these resonance problems. However, the motor current is small at low speeds, making it difficult to estimate the phase difference between the two motors as sensorless control. My research is underway to solve these problems and improve the stability of the system.

The method of suppressing resonance is studied by estimating the phase difference between the two motors by injected signals and using the estimated phase difference information.


Research Background and Theme 2:
Research of the control of two different motors

Conventional studies have shown that the performance of the two motors is guaranteed under the same conditions.
The case where the parameters of the two motors are different are as follows.

1) Inductance, resistance, etc. vary depending on the load difference between the two motors.

2) When driving two motors of different capacities

3) In the case of demagnetization of one of the two permanent magnet motors, the parameters may differ from each other.

In these cases, if the motor parameter difference increases, the system becomes unstable. Even if the parameters of the two motors are different, if a method to control this system is found, the degree of freedom of this system can be improved.



Single Inverter Dual synchronous Motors System

一般的には1つのインバータで1つの同期モータを駆動する。しかし、2つのモータが同じ速度で駆動されるシステムは、1つのインバータで2つのモータを駆動することができる。 このようなシステムは主に非同期モータ制御分野で適用された。同期モータシステムでは、2つのモータ間の負荷差などによりシステムが不安定になる問題がある。このような問題を解決するための研究が進められている。

これらのシステムは電気鉄道、2 fan sytemおよびconveyor beltシステムなどに適用できる

本システムのメリットは、パワー部品の減少によりコスト削減ができ、ドライブのサイズ削減も可能である。特に、低パワーシステムでは2つのパワー部品を使うよりも、2倍容量の1つのパワー部品を使う方がCost に有利である。
*制約事項 : 2モーターの速度は常に同じになる。










1) 2つのモータの負荷差により、インダクタンス、抵抗などが異なってくる。

2) 異なる容量の2つのモータを駆動する場合

3) 2つの永久磁石モータのうち、一つのモータが減磁される場合、互いにパラメータが異なる場合もある。

このような場合motor parameter差が大きくなると、やはりシステムが不安定になる。このようにモータパラメータが異なる場合でも駆動可能な方法を探せばシステムの自由度を向上させることができる。

  • Cheonsu Park, Shinji Doki,``Active Damping Control Method for Different Dual-Parallel-SPMSM Systems with Single Inverter'', IEEJ Journal of Industry Applications, 2023.
  • Cheonsu Park and Shinji Doki,``Control Method of Dual Parallel Surface-Mounted Permanent-Magnet Synchronous Motor Systems with Different Parameters Using Single Inverter'', ECCE 2022, 2022.
  • C. Park, S. Doki,``Stability Improvement Method of Position Sensorless Control for Single Inverter Dual Parallel IPMSMs Drive System by Using Signal Injection'', International Power Electronics Conference 2022, 2022.
  • パクチョンス・道木慎二,``Active Damping Control Method for Different Dual-Parallel-SPMSMs Systems with a Single Inverter'', 2022年電気学会産業応用部門大会講演論文集, 2022.