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A buck converter configured for a measurement of common- and differential-mode noise on the source. In order to simulate the common-mode noise, the capacitive coupling between the circuit and a reference plane must be included in the model. In this circuit, the capacitance between the switching node (between the high- and low-side transistors) and the reference plane is also included.
Model a custom transformer that exhibits hysteresis by using the Reluctance with Hysteresis block in a magnetic circuit. The transformer is rated for a 50W load and steps down from 120V to 12V rms. The magnetizing resistance Rm is modeled in the magnetic domain using an Eddy Loss block.
A low-cost voltage regulator circuit whose performance depends on both load current and temperature. Bias resistor R1 ensures that the voltage at the transistor base is close to the rated zener voltage. The regulator output voltage is also approximately at this voltage, the base-emitter voltage being a few tenths of a volt. The precise base-emitter voltage depends on the transistor working point (which in turn depends on the load) and also the temperature. Resistor R2 only serves to provide some protection in the event of a transient output short circuit.
A simple voltage regulator circuit constructed from discrete components. A fluctuating supply is modeled as 20V DC plus a 1V sinusoidal variation. The zener diode D1 sets the non-inverting input of the op-amp to 3.2V, and hence as the op-amp has a large gain, the op-amp inverting input and output are also at 3.2V. Hence the regulator voltage output is regulated to be 3.2*(1000+470)/470=10V. The NPN bipolar transistor is required to provide higher currents than is possible from a typical op-amp. The model can be used to check circuit operation, and to support selection of components to achieve the desired voltage regulation.
Create system-level model of a photovoltaic generator that can be used to simulate performance using historical irradiance data. Here the model is tested by varying the irradiance which approximates the effect of varying cloud cover. Power generation steps immediately following the irradiance change. Environmental temperature also varies during the test. The DC-AC converter efficiency is assumed to be a fixed 97 percent, this value having been determined from the ee_solar_converter example model.
Determine the efficiency of a single-stage solar converter. The model simulates one complete AC cycle for a specified level of solar irradiance and corresponding optimal DC voltage and AC RMS current. Using the example model ee_solar_characteristics, the optimal values have been determined as 342V DC and 20.05A AC for an irradiance of 1000W/m^2 and panel temperature of 20 degrees Celsius. Converter efficiency is determined in two independent ways. The first compares the ratio of AC power out to DC power in over one AC cycle. The second calculates losses by component by making use of Simscape™ logging. The small difference in calculated efficiency value is due to differences between trapezoidal integration used by the script and the greater accuracy achieved by the Simulink® variable-step solver.
Model a switching power supply that converts a 30V DC supply into a regulated 15V DC supply. The model can be used to both size the inductance L and smoothing capacitor C, as well as to design the feedback controller. By selecting between continuous and discrete controllers, the impact of discretization can be explored.
Model a switching power supply that converts a 30V DC supply into a regulated 15V DC supply. The model can be used to both size the inductance L and smoothing capacitor C, as well as to design the feedback controller. By selecting between continuous and discrete controllers, the impact of discretization can be explored. Modeling the switching devices as MOSFETs rather than ideal switches ensures that device on-resistances are correctly represented. The model also captures the switch-on/switch-off timing of the devices, this depending primarily on the gate capacitance values and the PWM driver output resistance.
Models the thermal dynamics of MOSFETs in a synchronous buck converter. It matches the structure of the Synchronous Buck Converter With Thermal Dynamics model (>> ee_switching_power_supply_thermal). Omitting the electrical switching dynamics allows the simulation to take much larger time steps, dramatically reducing the amount of time it takes for the simulation to calculate steady-state temperatures for the MOSFETS.
Model and assess the impact of component tolerances and fault events on the operation of a switching power supply. The R, L, and C components all have tolerances, operational limits, and faults defined. The faults can be enabled within the block dialog or using MATLAB® Commands. The capacitor fault is already enabled to cut in at 1.5e-3 seconds.
How a flyback converter can step-up a 5V DC source into a 15V DC regulated supply. The voltage is increased by creating a time-varying voltage across a transformer primary. The transformer steps up the voltage which is then rectified back to DC by the diode. Closed-loop control over the output voltage is effected by controlling the switching frequency on the primary side.
A DC-DC LLC power converter with frequency control. A simple integral control is implemented in Simulink® in the Controller block, and is designed to achieve a nominal output voltage defined by the variable Vout_nominal. The Output scope shows the frequency control signal, the output voltage, and the reference value for the output voltage. During startup, the reference value is ramped up to its desired setpoint. The design of the LLC powertrain is computed automatically using the first harmonic approximation.
A Class E power converter with frequency control. A simple integral control is implemented in Simulink® in the Controller block, and is designed to deliver 100W into a 5ohm load. The switch is an LDMOS, high-voltage transistor with a nonlinear capacitance model, and R Trans is the equivalent series resistance of the transformer. The Output scope shows the drain-source voltage for evaluation of the voltage stress on the switch. Note that, due to the nonlinear output capacitance of the transistor, the peak voltage stress is higher than would be expected if the output capacitance were constant. In addition, the scope also shows the frequency control signal, the output voltage, and the reference value for the output voltage. This model can be used to calculate the output power information from components in the circuit.
A LED driver based on a linear current regulator. The scope shows the light and current output and the supply voltage. The output comes into regulation for a supply voltage greater than about 12V.
How to parameterize the Simscape™ Electrical™ diode to represent a Transient Voltage Suppression (TVS) diode. This example is for a TVS diode suited to protecting automotive electronics from voltage transients associated with turning off inductive loads. To view the data extracted from the datasheet, select File->Model Properties->Callbacks and view the PreLoadFcn.
How a DC-DC converter can be used to maintain a constant load voltage when drawing power from an ultracapacitor. Initially the converter supplies power to the load, and as it does so, the capacitor voltage drops. The protection circuit disconnects the load when the capacitor voltage drops below a threshold of 4V. At 10 seconds the generator is turned on, and power is supplied to both the load and to the capacitor to recharge it.
How the performance of a rotational energy scavenger can be explored using a simple representative model. Electrical energy is produced from an off-center mass attached to the shaft of a DC motor. The mass, geometry, motor and electrical parameters must be matched to the expected mechanical excitation. The generated electrical power is less than the extracted mechanical power primarily due to motor winding losses and viscous damping for the rotor. This example is based on Nunna, K. "Constructive interconnection and damping assignment passivity-based control with applications", Imperial College London (2014). The model here is simplified in that the DC-DC converter is omitted.
How a fault may be applied to a MOSFET in a power converter in order to explore the operation of protection circuitry. After the MOSFET becomes faulted, the crowbar circuitry is activated in order to clamp the output voltage across the load and eventually to cause the fuse to blow.
How a varistor may be applied to a buck converter in order to protect the switching MOSFETs from over-voltages due to a differential surge.
A three-phase cable model comprised of multiple pi-sections. Each phase is enclosed in a conductive sheath. The conductive sheath is connected to ground at either end of the cable through a simple resistance. A high-voltage source provides power to an unbalanced resistive load through the power cable. You can configure the sheath to be either series-bonded or cross-bonded. You can also configure the number of pi-sections. Increasing the number of pi-sections improves the accuracy but slows down the simulation. To facilitate convergence, the voltage source includes an internal impedance.
The voltage output by a Supercapacitor block as it is charged and then discharged. To charge the Supercapacitor, a current of 100 mA is input to the Supercapacitor for 100 seconds. The Supercapacitor is then rested for one minute. For the next hour, to discharge the Supercapacitor, a load of 50 mA is stepped on for one second in every 50 seconds. The Supercapacitor is then rested until the end of the simulation. The scope displays the Supercapacitor charging/discharging current and voltage.
A high-voltage battery like those used in hybrid electric vehicles. The model uses a realistic DC-link current profile, which originates from a dynamic driving cycle. The total simulation time is 3600 seconds.
A custom frequency-dependent transmission line model. The characteristic admittance and propagation function are first derived from the frequency-dependent resistance, reactance, and susceptance. The derived values are fitted using
RF Toolbox™. The Universal Line Model (ULM)  is then implemented in
Simscape™ based on the fitted parameters. The results from the frequency-dependent transmission line model and the classic pi-section transmission line model are compared.
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