Motor : ECOHEART
Permanent Magnet Synchronus Motor (Brush-less DC Motor : DCBL)
Hitachi provides Total Solution for Motor Drive System
Background
- Diversity of customer demands toward specific motor drive systems.
- Strong ecological demands on environmental problems and energy saving.
- Customer demands for realizing both high efficiency and downsizing.
- Flexible system design to improve usefulness of motor drive systems.
- Systematic organization of open control network.
Drive System Trend
- Hitachi has been developing low cost systems equivalent to that of IM.
- More applications are expected, because of high efficiency, down sizing and low-noise.
Features
1. Actual Efficiency Example
- Rated Output 3.7kW
- Rated RPM 7200 min-1
- Rated Torque 0.5kgm
- Carrier Frequency 8kHz
|
RPM [rpm] |
Output [kw] |
Vdc [V] |
Inver [%] |
Motor Eff. [%] |
Total [%] |
|---|---|---|---|---|---|
| 7500 | 3.8 | 280 | 95.3 | 92.2 | 87.9 |
| 7200 | 3.7 | 278 | 95.6 | 91.4 | 87.4 |
| 6600 | 3.4 | 279 | 95.0 | 91.9 | 87.3 |
| 6000 | 3.1 | 281 | 94.6 | 91.7 | 86.8 |
| 4000 | 2.1 | 284 | 92.9 | 90.5 | 84.1 |
| 2000 | 1.0 | 282 | 88.3 | 87.6 | 77.4 |
2. Control method using sinusoidal wave form
Objectives
- Noise reduction by lowering torque ripple
- Efficiency Improvement by suppressing harmonics
| Current wave form |
Trapezidal wave form (120 degree) |
Sinusoidal wave form (180 degree) |
|---|---|---|
| Current harmonics | large | small |
| Torque ripple | large | small |
| Method of detecting induced voltage | Detecting circuit | Presumption by caculation |
| Method of detecting magnetic pole position |
During current zero period |
Presumption from current and voltage wave  |
| Subject | Quick response, Robustness | |
3. DCBL size and performance