Motor emulator
Embodiments relate to a motor simulator for an inverter under test (IUT), the motor simulator comprising: a voltage follower inverter for at least partially cancelling an output voltage of the IUT; and an output current control unit for controlling an output current of the IUT on the basis of an estimated current of a simulation target motor.
1. A motor emulator for an Inverter Under Test (IUT), comprising:
a voltage following inverter configured to cancel an output voltage of the IUT at least partially; and
an output current control unit configured to control an output current of the IUT based on the output voltage of the IUT and an estimated current of an emulation target motor,
wherein the voltage following inverter includes:
a DC terminal voltage source;
a first switching unit connected to the DC terminal voltage source in parallel and electrically connected to an output terminal of the IUT; and
a first switching control unit configured to control switching of the first switching unit based on the output voltage of the IUT and a predetermined threshold voltage.
2. The motor emulator according to claim 1 ,
wherein the first switching unit includes an upper-phase switch and a lower-phase switch connected in series, and
wherein the first switching control unit switches the upper-phase switch and the lower-phase switch by comparing the output voltage of the IUT with the predetermined threshold voltage.
3. The motor emulator according to claim 2 ,
wherein the first switching control unit is made of an electronic circuit that receives the output voltage of the IUT and the predetermined threshold voltage.
4. The motor emulator according to claim 1 ,
wherein the output current control unit includes:
a switching circuit electrically connected to an output terminal of the IUT; and
a second switching control unit configured to estimate a current of the emulation target motor based on the output voltage of the IUT and a characteristic of the emulation target motor and control switching of the switching circuit based on the estimated current.
5. The motor emulator according to claim 4 ,
wherein the switching circuit is made of a SiC MOSFET.
6. The motor emulator according to claim 4 ,
wherein the switching circuit is made of any one of a full bridge circuit, a half bridge circuit, or a linear power amplifier circuit.
7. The motor emulator according to claim 4 ,
wherein the characteristic of the emulation target motor includes at least one of magnetic flux interlinkage, magnetic saturation and spatial harmonics of the emulation target motor.
8. The motor emulator according to claim 4 , further comprising:
independent DC voltage sources configured to each provide a DC voltage to the switching circuit,
wherein the independent DC voltage sources of different phases are insulated from each other.
9. The motor emulator according to claim 1 , further comprising:
a filtering unit disposed between an output terminal of the IUT and the voltage following inverter,
wherein the filtering unit includes at least one of a single-phase inductor, a three-phase inductor and a zero sequence filter.