You can immediately notice that the motor took less time to get up to the required speed compared to the previous case. By requiring the motor to reach a speed of 1 rad/s, this is the transient that follows: Now we can set as an input a certain speed and see how the motor behaves in the transient.
In the second part of the code, I decided to put a PI regulator in series with the system and then use negative feedback to control the speed of the motor. I mean, we can vary the voltage and then get a certain speed as output but in most cases we need a certain speed regardless of the voltage (provided it is within the nominal voltage). This is a nice result but we can’t really control the motor. You can take a look at the transient of the angular speed variable in the graph below In this case it turns out that by applying a unit voltage step, the motor is absorbing 0.2 A and turning at a speed of 45.8 rad/s. Note that I’m assuming the torque of the mechanical load is constant in this case.Īs you can see in the comments in the code, the final state of the system can be calculated just by setting every derivative to zero and then solving for the state variables. Using Matlab we can simulate the system response to a unit voltage step. Mechanically speaking, the motor can be modelled by considering the following equation: The back EMF can be expressed as a function of the speed of the motor $e = k\phi\omega$. Usually R is very small and can be difficult to measure with a multimeter.
Where $R$ is the equivalent resistance of the brushes plus the windings, $L$ is the inductance as seen from the external terminals of the motor and $e$ is the back EMF. Use the G0 library and symbols for the G0 model and the G2 library and symbols for the G2 model.Electrically speaking, a permanent magnet DC motor can be modelled as follows:Īpplying LKT we obtain the following differential equation RevX are revision numbers, rev1, rev2, etc. (Product name)_G2_00_LTspice_revX_enc.asy G2 model symbol file for LTspice (Product name)_G2_00_LTspice_revX_enc.lib G2 model library file for LTspice (Product name)_G0_00_LTspice_revX_enc.asy G0 model symbol file for LTspice (Product name)_G0_00_LTspice_revX_enc.lib G0 model library file for LTspice (Product name)_G2_00_PSPICE_REVX_ENC.OLB G2 model symbol file for PSpice (Product name)_G2_00_PSpice_revX_enc.lib G2 model library file for PSpice (Product name)_G0_00_PSPICE_REVX.OLB G0 model symbol file for PSpice (Product name)_G0_00_PSpice_revX.lib G0 model library file for PSpice If you unpack it, you will find a total of four files in the unpacking folder: library files and symbol files for G0 and G2 model each.
If you select the desired model and click here, the zip file with the following name will be downloaded.įor PSpice model: (product name)_PSpice_(registration date).zipįor LTspice models: (product name)_LTspice_(registration date).zip G0 and G2 models can be downloaded from above linkage destination. The following shows the actual measurement of R-Load switching turn off waveform of the low voltage MOSFET device and L-load switching turn off waveform of the mid to high voltage MOSFET device, and the simulated waveforms of the G0 model and G2 model, respectively. While the SPICE models we have been publishing (called the G0 model in Toshiba) are standard device models and are suitable for function checking because of their fast computing speed, the SPICE models we have started publishing this time (also called the G2 model) enhance the reproducibility of the high current region characteristics of I D-V DS curve and the voltage-dependent characteristics of the parasitic capacitance, allowing us to simulate the switching with higher accuracy closer to actual measurement. In addition to those currently being published, Toshiba has begun publishing high precision SPICE models with high reproducibility of transient characteristics.
TOSHIBA CORPORATION has been publishing MOSFET device SPICE models for PSpice ® and LTspice ® on the Web.