You can do that by simply measuring the DC bus voltage of your inverter, than estimate the three current phases through the mathematical model of your VS inverter.
Is there is any problem with current measurement. The current measurement is substituted by current sensors which produce voltage. Such sensors are:
Current sensing or measuring resistance which is a very small resistance minimally disturbing the circuit. Then the voltage across this current sensing resistance is amplified using differential amplifiers and used as a control parameter.
The other method is to use Hall generators which senses the current without contacting.