Variable pulse train generation
Figure 1. The inverter provides several external speed control options.

You are not constrained to 32 kHz.
Page 112 shows that the max pulse frequency can be set parameter H6-02 at anywhere between 1 kHz to 32 kHz (and as low as 100 Hz on some models). Setting a lower frequency may simplify the microcontroller requirements.

Your other option is to PWM the A1 or A2 input with a 5 V signal via an RC low-pass filter but set the parameter for the input scaling to twice the maximum speed you want. (This is because your 5 V micro can only give 5 V at 100% PWM into the 0 to 10 V input.)

Any micro with a PWM controller with &geq; 12 bits should be able to do this for you - including d'Arduino.

Note also that there's a Modbus interface so you can probably set and read the speed (and a load of other parameters) on serial comms thereby avoiding any analog circuitry.