Abstract: A radio frequency inductive heating apparatus includes a control device, a plurality of radio frequency devices, a plurality of transformers, a resonant tank circuit, a heating element, and a first power supply. The radio frequency devices are selectively activated by the control device, and each of the plurality of radio frequency devices is operatively coupled to of the plurality of transformers. At least one of the plurality of radio frequency devices are selectively activated by the control device based on a power set signal and a feedback signal, the power set signal representing a desired output current associated with the resonant tank circuit, the feedback signal representing an electrical control parameter associated with the resonant tank circuit. A corresponding method is also disclosed.

Abstract: A radio frequency inductive heating apparatus includes a control device, a plurality of radio frequency devices, a plurality of transformers, a resonant tank circuit, a heating element, a first power supply, and a second power supply. The radio frequency devices are selectively activated by the control device, and each of the plurality of radio frequency devices is coupled to the primary winding of one of the plurality of transformers. The secondary winding of each of the plurality of transformers is coupled to the resonant tank circuit, and the heating element is coupled to the resonant tank circuit. The plurality of radio frequency devices includes a first radio frequency device and a second radio frequency device. The first radio frequency device is coupled to the first power supply, and the second radio frequency device is operatively coupled to the second power supply. A corresponding method is also disclosed.

Abstract: A radio frequency inductive heating apparatus includes a control device, a plurality of radio frequency devices, a plurality of transformers, a resonant tank circuit, a heating element, and a first power supply. The radio frequency devices are selectively activated by the control device, and each of the plurality of radio frequency devices is operatively coupled to of the plurality of transformers. At least one of the plurality of radio frequency devices are selectively activated by the control device based on a power set signal and a feedback signal, the power set signal representing a desired output current associated with the resonant tank circuit, the feedback signal representing an electrical control parameter associated with the resonant tank circuit. A corresponding method is also disclosed.

Abstract: A radio frequency inductive heating apparatus includes a control device, a plurality of radio frequency devices, a plurality of transformers, a resonant tank circuit, a heating element, a first power supply, and a second power supply. The radio frequency devices are selectively activated by the control device, and each of the plurality of radio frequency devices is coupled to the primary winding of one of the plurality of transformers. The secondary winding of each of the plurality of transformers is coupled to the resonant tank circuit, and the heating element is coupled to the resonant tank circuit. The plurality of radio frequency devices includes a first radio frequency device and a second radio frequency device. The first radio frequency device is coupled to the first power supply, and the second radio frequency device is operatively coupled to the second power supply. A corresponding method is also disclosed.

Abstract: An RF power amplifier system is presented herein and it includes an RF source that provides an RF carrier signal having a given RF carrier frequency. An RF amplifier module amplifies the carrier signal and this module includes first and second RF amplifiers having a common input to receive a turn on signal that turns on both amplifiers and wherein the outputs of the amplifiers are coupled together in parallel. A controller supplies a turn on signal to the common input to turn on the first and second amplifiers. A first AC to DC supply provides a first DC operating voltage obtained from a first multiphase AC supply and applies this to the amplifier module and wherein the first DC voltage exhibits a ripple frequency dependent upon the number of phases in the first multiphase supply.

Abstract: An RF power amplifier system is provided having a DC voltage source for providing an input DC voltage. An RF source provides an RF cattier signal. An RF amplifier serves to amplifier the carrier signal. A DC to DC power supply provides operating voltage to the RF amplifier wherein the operating voltage exhibits a desired percentage of the input voltage. The DC to DC supply includes a low pass filter having a capacitor. A switching device is periodically turned on by turn on pulses for periodically applying the input voltage to the filter which then provides an output voltage across the capacitor. The output voltage serves as the operating voltage. A pulse generator provides the turn on pulses at a frequency synchronized to the frequency of the carrier signal. The turn on pulses exhibit a duty cycle that varies as a function of the value of a control signal. A comparator compares the input voltage with the output voltage and provides the control signal with a value that varies as a function of the comparison.