2.4 Electric Parameters

Input Voltage

Main power supply input: DC 24V ~ 48V

Driver power supply input: 12V

Phase Current

The phase current is constrained by the rated current $I_{r a t e d}$ $I_{r a t e d}$ , which defines the maximum current that can be endured by the driver board.

$I_{r a t e d}^{p e a k} = 30 A$ $I_{r a t e d}^{p e a k} = 30 A$

$I_{r a t e d}^{R M S} = 15 A$ $I_{r a t e d}^{R M S} = 15 A$

A current bigger than $I_{r a t e d}$ $I_{r a t e d}$ can cause damage on the driver board.

DC Bus Current

The DC bus current is constrained by the over-current (OC) threshold $I_{o c}$ $I_{o c}$ .

$I_{o c}$ $I_{o c}$ is the smallest transient DC bus current which triggers the over-current event on the control board. $I_{o c}$ $I_{o c}$ depends on the shunt resistance on the driver board and the OC circuit on the control board. The control board triggers an OC event if the regulated signal is not less than $\frac{1}{2} A V D D$ $\frac{1}{2} A V D D$ ; and the regulated signal is $I_{o c} \times R_{s h u n t}^{b u s} \times G^{b u s}$ $I_{o c} \times R_{s h u n t}^{b u s} \times G^{b u s}$ , therefore:

$I_{o c} = \frac{A V D D}{2 \times R_{s h u n t}^{p h a s e} \times G^{p h a s e}}$ $I_{o c} = \frac{A V D D}{2 \times R_{s h u n t}^{p h a s e} \times G^{p h a s e}}$ .

Where,

$R_{s h u n t}^{b u s}$ $R_{s h u n t}^{b u s}$ is the shunt resistance for the DC bus current

$G^{b u s}$ $G^{b u s}$ is the regulating circuit’s gain for the DC bus current sample signal

AVDD is the analog power supply voltage for the ADC

$G^{b u s}$ $G^{b u s}$ and AVDD are fixed for a certain control board, while $R_{s h u n t}^{b u s}$ $R_{s h u n t}^{b u s}$ can be modified by the user. In other words, $I_{o c}$ $I_{o c}$ can be defined by the user by selecting $R_{s h u n t}^{b u s}$ $R_{s h u n t}^{b u s}$ .

$R_{s h u n t}^{b u s}$ $R_{s h u n t}^{b u s}$ is recommended to be selected in such a manner that $I_{o c}$ $I_{o c}$ is not bigger than $I_{r a t e d}$ $I_{r a t e d}$ .