Delta Electronics, Inc.

Lung-Jay Cheng

Ting-Chung Hsieh

Shih-Chieh Liao

Jen-Hsiang Huang

Chun-Ju Wu

Yao-Sheng Wu

A method of estimating a d-q axis inductance of a permanent magnet synchronous motor includes the following steps. First, building an equivalent motor control block through enabling two of the three phases, and disabling the remaining one of the three phases, and locking a rotor. Afterward, incorporating a back EMF observer into a DC motor control block, and making the DC motor control block correspond to the back EMF observer by commanding an angular speed of the DC motor control block to be zero. Afterward, introducing the equivalent motor control block into the DC motor control block, and using the back EMF observer to estimate the back EMF, and repeating above steps taking turns to disable one phase so as to obtain three sets of motor inductances respectively. Finally, estimating the d-q axis inductance by introducing the three sets of equivalent motor inductances into an inductance relational equation.

Method of estimating D-Q axis inductance of permanent magnet synchronous motor

A dead-time compensation method is applied to a PWM inverter, which is provided to drive an induction motor using a constant V/f control. The method first calculates a root-mean-square current of the output instantaneous current of the inverter. Afterward, a lookup table of the root-mean-square current is used to obtain a dead-time compensation base voltage and a dead-time compensation per-unit voltage. Finally, the dead-time compensation base voltage is multiplied by the dead-time compensation per-unit voltage to produce a dead-time compensation voltage of the PWM inverter. Accordingly, the method reduces complexity of converting the current to the voltage to reach a faster real-time response. Furthermore, a more accurate dead-time compensation voltage is obtained without increasing hardware costs and the efficiency of operating the induction motor is improved at low speed and light load condition.

Dead-time compensation apparatus of PWM inverter and method thereof

A method of detecting an output phase loss (OPHL) for a motor drive detects an abnormal OPHL operation when at least one phase of a three-phase current is continually zero. Each phase of the three-phase current is acquired, sampled, filtered, and compared. Hence, a corresponding zero-current counter value is continually added, and a corresponding abnormal current value is set as logic 1 when a zero-phase current of the three-phase current is continually zero. Finally, an OPHL certified value is set as logic 1 to confirm that the motor driver is operated in the abnormal OPHL operation. Therefore, a direct-current and an alternating-current OPHL can be detected before and after the motor driver is operated, respectively.

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Taipei, Taiwan

Lung-Jay Cheng