| 摘要 |
1515127 Automatic control of power and temperature LICENTIA PATENT VERWALTUNGS GmbH 22 May 1975 [22 May 1974] 22402/75 Heading G3R An arrangement for controlling the power delivered to an A.C. load through anti-parallel thryristors includes circuits for deriving signals indicative of the load current and voltage. One of these signals is then used by a modulation circuit to switch the other signal for time periods related to its magnitude, so that an output indicative of actual power is produced for comparison with a reference value. The timing ratio and switching frequency of the thyristors are controlled in dependence on the comparison. As shown in Fig. 1, the temperature of a load V supplied from A.C. lines N is measured by a sensor F and compared with a desired value to form a required value signal PSOLL for the power to be supplied to the load. Rectifiers G1, G2 produce signals proportional to the load current and voltage respectively, the current signal being used to determine the timing ratio and frequency of a multivibrator M including an operational amplifier O1. The output of the multi-vibrator switches a transistor p connected to the output of the rectifier G2 so that an actual load power signal P IST is formed and then summed with the required valve signal P SOLL . The resulting difference signal is fed by way of a comparing operational amplifier 02 to a synchronizing circuit S which controls the firing of antiparallel thyristors Th1, Th2 and thereby regulates the power supplied to the load V so as to maintain it at the desired temperature. |
