Transcript Twelve-Step_Sensorless_Drive_Scheme_for_a_Brushless_DC_Motor

Investigation_of_Effectiveness_of_Sensorless_Operation_in_CarrierSignal-Injection-Based_Sensorless-Control_Methods
南台科技大學電機工程系
來源: Zhu, Z. Q. Gong, L. M., “Investigation of Effectiveness
of Sensorless Operation in Carrier-Signal-Injection-Based
Sensorless-Control Methods,” IEEE TRANSACTIONS ON
INDUSTRIAL ELECTRONICS, VOL. 58, NO. 8, pp. 3431 – 3439,
AUGUST 2011.
學生:林柏辰
指導老師:王明賢
Abstract—This paper investigates the effectiveness of sensorless
operation in carrier-signal-injection-based sensorless-control
methods for permanent-magnet brushless ac motors. The sensorless
safety operation area (SSOA) is introduced with due account
for the quantization error in the analog to digital conversion. The
SSOA defines a working area in the d–q plane in which the motor
can operate in sensorless mode with a guaranteed performance
in steady state. With the aid of SSOA, a proper injected carrier
signal can be selected for the specific prototype machine and
current-measurement resolution. Experimental results confirm
that the performance of sensorless operation can be guaranteed
when the machine operates inside the SSOA with cross-saturation
compensation.
INTRODUCTION
SENSORLESS control of permanent-magnet (PM) brushless
ac (BLAC) motors is attractive for its inherent
advantages, such as increased reliability, reduced cost and
size, etc. Its techniques can be categorized into two major
types: fundamental-model-based and saliency-tracking-based
methods. The algorithms relying on the fundamental model
consist of the back-electromotive-force-based [1]–[9] and fluxlinkagebased methods [10]–[13]. They have the advantages of
straightforwardness and simplicity, and a good performance can
be achieved in the middle and high-speed regions. However, under
the conditions of low speed and standstill, the fundamental
model of a machine usually results in the failure of sensorless
control. To solve this problem, saliency-tracking-based methods
are developed [14]–[26]. Due to the inherent saliency of PM
BLAC motors resulting from either geometrical rotor saliency
or saturation-induced saliency, the position information can be
tracked via position-dependent current response by injecting
discrete voltage pulses [14], modified pulsewidth-modulation
pulses [15] or continuous high-frequency carrier-voltage signal
[16]–[26] into the motors.
EXPERIMENTAL RESULTS
The hardware platform to evaluate the effectiveness of
sensorless operation is constructed based on a TMS320C31
floating-point DSP. Three dedicated 12-b AD converters are
used to measure the phase current with the aid of current transducers.
To verify the accuracy of the estimated rotor position,
the real rotor position from an encoder with a resolution of
1024PPR is provided to the DSP. The calculation rate of the
current loop is configured to be 5 kHz, which is the same as the
current-sampling frequency.
End