Vibration protection in a variable speed compressor

A method comprising:

• storing, with a control module that controls an operating frequency of a variable speed compressor operable at a plurality of frequencies, at least one prohibited frequency range that includes a resonant frequency of the variable speed compressor;
• storing, with the control module, an allowed upper frequency and an allowed lower frequency for each prohibited frequency range of the at least one prohibited frequency range, the allowed upper frequency being above the associated prohibited frequency range and the allowed lower frequency being below the associated prohibited frequency range;
• determining, with the control module, a requested frequency for operating the variable speed compressor;
• comparing, with the control module, the requested frequency with the at least one prohibited frequency range;
• operating, with the control module, the variable speed compressor at the requested frequency when the requested frequency is outside of the at least one prohibited frequency range;
• determining, with the control module, an upper frequency operating time and a lower frequency operating time when the requested frequency is within the at least one prohibited frequency range;
• and
• operating, with the control module, the variable speed compressor at the allowed upper frequency for the upper frequency operating time and at the allowed lower frequency for the lower frequency operating time when the requested frequency is within the at least one prohibited frequency range;
• wherein the upper frequency operating time and the lower frequency operating time are determined such that a time-averaged frequency output over the upper frequency operating time and the lower frequency operating time corresponds to the requested frequency.