A simplified vector control is proposed as a driving method of permanent magnet synchronous motor (PMSM) for electrical household appliances. Control structure is simplified by eliminating the speed regulator and the current regulator from the conventional vector controller. Output voltage references are determined by feedforward-like calculation using motor parameters, rotation speed command, and current references. In the static characteristic, the proposed vector control method is almost equal to the conventional one, because the voltage references are calculated in the vector space. A practical estimate equation of rotor position is proposed, and the phase locked loop control approach is employed to drive PMSM without position and speed sensors. Design method of two control gains is given. Finally, the effectiveness of the proposed control is verified by simulation and experiments.
SUMMARYPublic-key cryptography such as RSA cryptography and elliptic curve cryptography are used in electronic transactions. Since the security of the cryptography depends on the cryptographic key which is stored on an IC chip, security was believed to have been established as long as we use smart cards. However, since the mid-1990s, one technique after another has been developed for extracting the secret key without unsealing the IC chip. In particular, the power analysis by Kocher's group is an attack that can be carried out by using practical resources, and various applications have been proposed. In this paper, we study the power analysis of modular exponentiation, which is a primitive of RSA cryptography, and its countermeasures. Specifically, starting with the countermeasures to single-exponent multiple-data (SEMD), multiple-exponent single-data (MESD), and zero-exponent multiple-data (ZEMD) attacks of Messerges's group, we illustrate feasible attacks such as the Big Mac attack of Walter and Thompson, the template attack of Chari's group, and an attack proposed by the authors. We propose a countermeasure and present an implementation in a smart card. If the proposed method is applied to 1024-bit modular exponentiation, adequate security can be obtained in a processing time less than twice the time without countermeasures.
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