| 摘要 |
PROBLEM TO BE SOLVED: To enable high speed current control even when a low price A/D, D/A converter having low resolution is used in a digital current detecting circuit. SOLUTION: In a current control apparatus for detecting a current of inverter 1 with HCT2, detecting a digital current with a current detecting circuit 3, latching S1 current detection with a PWM synchronous sample signal T in a current control arithmetic section 5 to conduct proportional and integral operation for the PWM control of the inverter with this voltage command, a current detecting circuit 3 is formed as a balanced current detecting circuit which executes sample-holding 32 of an error between the detecting current from HCT 2 and a D/A converted 36 feedback current detection and than A/D conversion 33 and integration 34. The digital conversion is conducted by considering the basic clock NT of this circuit as the signal obtained by conducting N-multiplication (8) of the current sample frequency T. Since the basic clock NT of a current detecting circuit of this apparatus is a high frequency signal synchronized with the current sample signal T, high precision current detection can be realized without generation of beat. |
