129 results about "Dead time compensation" patented technology

A microcomputer includes an actual DUTY value detection section that detects an actual DUTY value γx by measuring the ratio of time in which an output voltage of each phase becomes a power supply voltage in a cycle of a triangular wave. A dead time compensation computation section subtracts the actual DUTY value γx from a DUTY instruction value αx before correction, thereby computing a difference value Δx. Subsequently, the dead time compensation computation section adds the difference value Δx to dead time compensation amounts βxp, βxm, which have been used for correcting the DUTY instruction value αx, thereby determining new dead time compensation amounts βxp′ and βxm′. The dead time compensation amounts βxp, βxm stored in a memory are renewed with the new dead time compensation amounts βxp′, βxm′.

To provide an apparatus for controlling an electric power steering apparatus such that, by correcting a dead time compensation amount on the basis of the temperature of a switching element, inconsistency between a dead time and a dead time compensation value can be limited, distortion in motor current or development of torque ripple can be suppressed, dead time compensation can be performed in accordance with a steering condition so as to suppress the generation of noise, and high steering performance can be obtained from low-temperature to high-temperature environment. [Solution] The control apparatus is provided with: a dead time characteristics unit for calculating a dead time characteristic value; a steering state determination unit for determining a steering state; a gain unit for varying the gain of the dead time characteristic value in accordance with the determination of the steering state; a sign determination unit for determining a sign on the basis of a detected current or a current command value of a motor or a model current value by using a sign determination method which is switched in accordance with the determination of the steering state; a temperature sensor for detecting an inverter temperature; a dead time temperature correction value calculation unit for calculating a dead time temperature correction value corresponding to the temperature; and an arithmetic processing unit for arithmetically processing the dead time compensation value to which the sign is allotted with the dead time temperature correction value with respect to an output from the gain unit so as to output a dead time compensation value.

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.