Method for operating a frequency converter circuit

A cooktop including:

• a pair of induction coils;
• and
• a frequency converter circuit having a first output connected to a first of the pair of induction coils and a second output connected to a second of the pair of induction coils, the pair of induction coils being either individually or simultaneously operable,
• the first output being associated with a first switching frequency and the second output being associated with a second switching frequency, wherein, if the first and second switching frequencies are different from one another, noise having a noise frequency is generated when the pair induction coils is operated simultaneously,
• wherein the first switching frequency and the second switching frequency are set or configured to have values such that the noise frequency is either above or below a human audibility threshold range associated with first and second cut-off frequencies, the second cut-off frequency being higher than the first cut-off frequency, and
• wherein, when the first switching frequency is set for a user operated power setting and a selected switch-on time, the second switching frequency is selected to be in a range of frequencies extending from the first switching frequency to a sum of the first switching frequency and the first cut-off frequency, and/or above a sum of the first switching frequency and the second cut-off frequency, the second switching frequency being associated with the selected switch-on time.

A cooktop including:

• a pair of induction coils;
• and
• a frequency converter circuit having a first output connected to a first induction coil of the pair of induction coils and a second output connected to a second induction coil of the pair of induction coils, the pair of induction coils being either individually or simultaneously operable,
• the first output being associated with a first switching frequency and the second output being associated with a second switching frequency, wherein noise having a noise frequency is generated by superposition of the first switching frequency and the second switching frequency when the pair induction coils is operated simultaneously;
• wherein the first switching frequency and the second switching frequency are set to have values such that the noise frequency is either above or below a human audibility threshold range associated with first and second cut-off frequencies, the second cut-off frequency being higher than the first cut-off frequency, and
• wherein the frequency converter circuit is configured to control the first induction coil to operate at a first switching frequency for a user operated power setting at a selected switch-on time of 0.5, and the frequency converter circuit is configured to determine the second switching frequency along the selected switch-on time and taking into account the first and second cut-off frequencies.

A cooktop including:

• a pair of induction heating units;
• and
• a frequency converter circuit having a first output connected to a first induction heating unit of the pair of induction heating units and a second output connected to a second induction heating unit of the pair of induction heating units, the pair of induction heating units being either individually or simultaneously operable,
• the first output being associated with a first switching frequency and the second output being associated with a second switching frequency different from the first switching frequency in which case noise having a noise frequency is generated by superposition of the first switching frequency and the second switching frequency when the pair induction heating units is operated simultaneously;
• wherein the frequency converter circuit is configured to set or determine the first switching frequency and the second switching frequency such that the noise frequency is generally outside a human audibility threshold range, or only insignificantly within it, during simultaneous operation,
• wherein the frequency converter circuit is configured to establish the first switching frequency for a first user selected power setting and a selected switch-on time, and to establish the second switching frequency for a second user selected power setting for the selected switch-on time, and wherein the second switching frequency is (1) substantially equal to the first switching frequency, and/or (2) equal to or above a sum of the first switching frequency and an upper cut-off frequency associated with the threshold range.

A converter circuit for an induction cooking device having first and second induction coils, the converter circuit comprising:

• an inlet connectable to a voltage source;
• a first circuit having a high frequency switch converting power from the voltage source to a first high frequency output power applied to the first induction coil, wherein the first high frequency output power has a frequency (f1) corresponding to a switching frequency of the first high frequency switch;
• a second circuit having a high frequency switch converting power from the voltage source to a second high frequency output power applied to the second induction coil, wherein the second high frequency output power has a frequency (f2) corresponding to a switching frequency of the second high frequency switch,
• wherein the difference between the frequencies f2 and f1 is no greater than a predetermined lower threshold and is no less than a predetermined higher threshold, and
• wherein the converter circuit regulates the power of the second high frequency output power by selecting the frequency f2 and a duration during which the second high frequency output power has the frequency f2 in a repeating cycle applied to the second high frequency output power.

An induction cooking device comprising:

• a first induction heating element;
• a second induction heating element;
• a frequency converter circuit including a first power output electrically coupled to the first induction heating element and a second power output electrically coupled to the second induction heating element;
• the frequency converter circuit generating a first power output signal applied to the first power output, wherein the first power output signal has a first switching frequency;
• the frequency converter circuit generating a second power output signal applied to the second power output, wherein the second power output signal has a second switching frequency;
• wherein the second switching frequency is selected by the induction cooking device to be no greater than a first cut-off frequency and no less than a second cut-off frequency, wherein the second cut-off frequency is higher than the first cut-off frequency, and
• wherein the induction cooking device regulates an electrical power applied to at least one of the first and second outputs by adjusting the switching frequency and a duration during which at least one of the first and second switching frequencies are applied in a repeating cycle during which the electrical power applied to the at least one of the first and second outputs.

A cooktop including:

• a pair of induction coils;
• and
• a frequency converter circuit having a first output connected to a first of the pair of induction coils and a second output connected to a second of the pair of induction coils, the pair of induction coils being either individually or simultaneously operable,
• the first output being associated with a first switching frequency and the second output being associated with a second switching frequency, wherein, if the first and second switching frequencies are different from one another, noise having a noise frequency is generated when the pair induction coils is operated simultaneously,
• wherein the first switching frequency and the second switching frequency are set or configured to have values such that the noise frequency is either above or below a human audibility threshold range associated with first and second cut-off frequencies, the second cut-off frequency being higher than the first cut-off frequency, and
• wherein, when the first switching frequency is set for a user operated power setting and the second switching frequency is selected to be in a range of frequencies extending from the first switching frequency to a sum of the first switching frequency and the first cut-off frequency, and/or above a sum of the first switching frequency and the second cut-off frequency, the second switching frequency being associated a selected duration during which the second switching frequency is applied to second output.

A cooktop including:

• a pair of induction heating units;
• and
• a frequency converter circuit having a first output connected to a first induction heating unit of the pair of induction heating units and a second output connected to a second induction heating unit of the pair of induction heating units, the pair of induction heating units being either individually or simultaneously operable,
• the first output being associated with a first switching frequency and the second output being associated with a second switching frequency different from the first switching frequency in which case noise having a noise frequency is generated by superposition of the first switching frequency and the second switching frequency when the pair induction heating units is operated simultaneously;
• wherein the frequency converter circuit is configured to set or determine the first switching frequency and the second switching frequency such that the noise frequency is generally outside a human audibility threshold range, or only insignificantly within it, during simultaneous operation,
• wherein the frequency converter circuit is configured to establish the first switching frequency for a first user selected power setting and to establish the second switching frequency for a second user selected power setting, wherein the second switching frequency being associated a selected duration during which the second switching frequency is applied to second output, and
• wherein the second switching frequency is (1) substantially equal to the first switching frequency, and/or (2) equal to or above a sum of the first switching frequency and an upper cut-off frequency associated with the threshold range.