Ignition control device for a converter

Claim 2

An ignition control device for a converter having converter valves and a free oscillating oscillator having an input voltage and an output voltage independent of its input voltage which permits the regulation of the converter valves at variable ignition angles and in a predetermined sequence, said ignition control device comprising controlled quantity means for deriving a controlled quantity in the converter; and phase control means connected to the oscillator and the controlled quantity means for controlling the phase of the output voltage of the oscillator in dependence upon the controlled quantity.

Claim 3

An ignition control device as claimed in claim 1, wherein the controlled quantity means derives the load current of the converter as the controlled quantity.

Claim 4

An ignition control device as claimed in claim 1, wherein the oscillator provides a reference voltage UR which increases in proportion to time, and further comprising regulating means connected to the controlled quantity means for providing an output control voltage US in dependence upon the controlled quantity Ii, threshold means providing a threshold level and connected to the regulating means and the oscillator for comparing the control voltage and the reference voltage UR and for producing a pulse when the difference between the control voltage US and the reference voltage UR reaches said threshold level , and reset means connected to the threshold means for resetting the reference voltage UR of the oscillator by a constant magnitude U''R and for releasing an ignition pulse for a converter valve with the pulse of the threshold means.

Claim 5

An ignition control device as claimed in claim 1, further comprising frequency control means connected to the oscillator for controlling the frequency of the oscillator in dependence upon the controlled quantity.

Claim 6

An ignition control device as claimed in claim 3, wherein the reference voltage means comprises an integrator and a source of constant direct voltage UE connected to the integrator.

Claim 7

An ignition control device as claimed in claim 3, wherein the reset means comprises a monostable multivibrator releasable when the difference between the output control voltage (US) and the reference voltage (UR) reaches the threshold level of the threshold means.

Claim 8

An ignition control device as claimed in claim 6, further comprising a ring counter connected to the monostable multivibrator, said multivibrator producing a pulse for stepping the ring counter.

Claim 9

An ignition control device as claimed in claim 7, further comprising a source of alternating voltage connected to the converter and threshold means connected to the source of alternating voltage for controlling the phase of the oscillator output voltage in a range between two threshold levels in accordance with an ignition angle Alpha o 0* and 0* < Alpha 1 < 180*, the two threshold levels being derived from the alternating voltage of said source of alternating voltage.

Claim 10

An ignition control device as claimed in claim 8, wherein the source of alternating voltage provides a three phase alternating voltage each phase providing two pulses shifted in 180* phase opposition relative to the period of alternating voltage, and the threshold means comprises logical circuitry for deriving from the two pulses of each phase and from the ignition pulses of the converter valves, the two threshold levels corresponding to the ignition angles Alpha 0 and Alpha 1, the threshold level corresponding to the ignition angle Alpha o being utilized to block the monostable multivibrator independently of the sum of the comparison result and the threshold level corresponding to the ignition angle Alpha 1, being utilized to regulate the monostable multivibrator.

Claim 11

An ignition control device as claimed in claim 9, further comprising a first plurality of AND gates each having inputs and an output, an OR gate having a plurality of inputs each connected to the output of a corresponding one of the first plurality of AND gates and an output, and an AND gate having one input connected to the output of the OR gate, a second input connected to the output of the threshold means and receiving the comparison result and an output coNnected to the monostable multivibrator for providing an output signal for controlling the monostable multivibrator, and wherein the ring counter has a plurality of outputs each connected to an input of a corresponding one of the first plurality of AND gates and the threshold means is connected to corresponding inputs of the first plurality of AND gates and supplies the pulses from the source of alternating voltage to inputs of corresponding ones of the first plurality of AND gates.

Claim 12

An ignition control device as claimed in claim 10, further comprising a second plurality of AND gates each having inputs and an output, a second OR gate having a plurality of inputs each connected to the output of a corresponding one of the second plurality of AND gates and an output, and another OR gate having one input connected to the output of the second OR gate, a second input connected to the output of the AND gate and receiving the comparison result of the threshold means and an output connected to the monostable multivibrator for providing an output signal for controlling the monostable multivibrator, and wherein each of the outputs of the ring counter is connected to an input of a corresponding one of the second plurality of AND gates and the threshold means is connected to corresponding inputs of the second plurality of AND gates and supplies the pulses from the source of alternating voltage to inputs of corresponding ones of the second plurality of AND gates.

Claim 13

An ignition control device as claimed in claim 11, further comprising a second monostable multivibrator having an adjustable pulse duration, an input coupled to the output of the second OR gate and an output connected to the one input of the other OR gate.

Claim 14

An ignition control device as claimed in claim 12, wherein the reference voltage means comprises an integrator having a curved characteristic and a source of constant direct voltage UE connected to the integrator for providing a reference voltage UR which increases with time, the threshold means compares the output control voltage US of the regulating means and the reference voltage, the reset means utilizes the threshold level of the comparison result to reset the reference voltage means by a constant magnitude, and the reference voltage means provides a reset pulse for releasing an ignition pulse for a converter valve.