1HP VFD

The major source of problems in the real world is conducted emissions and these are typically in the region of 20kHz to 10MHz. The source of the emissions is the output of the VFD which comprises 6 solid state switches that switch each output between the DC bus rails. These switches are typically high speed IGBTs which can switch in less than 100nS.
The output waveform is a PWM waveform designed to create a sinusoidal current flow into the motor.

All VFD applications require programming. You have to make it do what you want. Parameters like minimum and maximum frequencies, number of motor poles, maximum current, overload response, braking behavior, acceleration profiles, etc. must be set by the user to match your installation's needs. The voltage/frequency curve is user configurable too, which is very useful for your kind of application where you are operating outside the normal frequency range of the motor. Good VFDs come with a display that can be set to show the motor speed (or any number of other parameters). If I were doing this, I would use a 1HP 208V two-pole motor and a 1HP VFD with a 240V input.

One feature that is present in the Mitsubishi VFD and not present in cheaper units that I have installed is a braking resistor. These are used in applications where you want to use the motor as a brake to stop the machine or control the speed of a descending load. The bigger the resistor, the quicker the stop can be programmed in. You can eliminate coasting, even under significant load, when using a resistor. A unit without this resistor built in is quite a bit smaller in size and less expensive. Often an external resistor can be added to the cheaper units if you decide you want to add one later, but at least you aren't paying for it when you don't need it.