Abstract: Techniques to reduce discontinuities in power, for example, by controlling an electrical power output of an active front end unit during a transition between a first operating mode and a second operating mode. In some examples, to reduce discontinuities, a control unit of the active front end unit can seed the integrator of proportional-integral (PI) controllers that are brought online during the operating mode change with a value that represents the proper state of the current system, such as the measured or calculated value of the component the PI controller is controlling). In other examples, to reduce discontinuities, a control unit of the active front end unit can control reference frame alignment during a transition between a first operating mode and a second operating mode.

Abstract: Techniques are described that address the unequal loss distribution between switches in the top half and the bottom half of the primary side full bridge circuit of the H bridge of two-level SAB and DAB converters. The techniques involve dynamically controlling the duty cycles of power switches in the top and the bottom switches of the primary side full bridge circuit and, as a result, balancing their temperature. In particular, the duty cycles of the switches may be “toggled” after N cycles of an operating cycle pattern so as to invert the duty cycles of the complementary switches. Inverting the duty cycles of the complementary switches reverses (or “toggles”) the duty cycles between the complementary switch pairs. By implementing this approach, the techniques achieve a balanced loss distribution between the two halves, thereby facilitating higher power density operation.

Abstract: Techniques to reduce discontinuities in power, for example, by controlling an electrical power output of an active front end unit during a transition between a first operating mode and a second operating mode. In some examples, to reduce discontinuities, a control unit of the active front end unit can seed the integrator of proportional-integral (PI) controllers that are brought online during the operating mode change with a value that represents the proper state of the current system, such as the measured or calculated value of the component the PI controller is controlling). In other examples, to reduce discontinuities, a control unit of the active front end unit can control reference frame alignment during a transition between a first operating mode and a second operating mode.

Abstract: This disclosure describes techniques that address the unequal loss distribution between switches in two H bridge legs of two-level PSFB and DAB converters, where one leg reaches its temperature limit sooner than the other leg due to imbalanced losses. The techniques involve dynamically controlling the switching states of power switches in both legs simultaneously in order to maintain a consistent equivalent phase shift angle between those legs at the given operating point while enabling each leg to dynamically alternate between leading and lagging positions. The dynamic switching state transitions may be seamless, so as not to introduce any transients into the rest of the circuit. By implementing this approach, the techniques achieve a balanced loss distribution between the two legs, thereby facilitating higher power density operation.

Abstract: Techniques are described to continuously calculate an inverter DC power of a synchronous machine, e.g., motor or generator, based on the individual phase currents, DC link voltage, and gate signals, which can be compared against the commanded mechanical power based of the estimated rotor speed and commanded torque. A controller can determine whether to shut down the inverter, such as the pulse width modulation (PWM), if the DC power is greater than a threshold value. Such a threshold can be defined to allow an acceptable position and speed estimation error margin.

Abstract: Capacitor voltage balancing techniques are described for a 3-level 3-level dual-active-bridge converter that controls the duration of a zero voltage state of the low voltage (LV) and medium (MV) side transformer voltages based on a voltage difference between the upper and lower capacitors of both the LV and MV sides independently, the power delivered (P), and the LV and MV DC voltages. This control varies the angle to maintain the power requirement, which induces the additional voltage drop across the transformer inductance to produce the required current to flow through the capacitors and balance the capacitor voltages.

Abstract: An interface circuit to interface an energy source to a power bus of a microgrid includes a switching inverter circuit, an output filter circuit coupled between an output of the three-phase inverter circuit and the power bus, and a control circuit loop to control switching of the switching inverter circuit. The control circuit loop is coupled to the output filter circuit and the switching inverter and includes a proportional-integral oscillator-based repetitive (PIOR) controller.

Abstract: An interface circuit to interface an energy source to a power bus of a microgrid includes a switching inverter circuit, an output filter circuit coupled between an output of the three-phase inverter circuit and the power bus, and a control circuit loop to control switching of the switching inverter circuit. The control circuit loop is coupled to the output filter circuit and the switching inverter and includes a proportional-integral oscillator-based repetitive (PIOR) controller.

Abstract: A system for managing power transfer with a power grid can include a DC-to-alternate current (AC) inverter, an output filter, and a load controller. The DC-to-alternate current (AC) inverter can be configured to output an output voltage (VOUT). The output filter can be configured to receive an output voltage (VOUT) and generate a capacitor voltage vector (VCAP) across a capacitor, the capacitor voltage vector (VCAP) including a second axis component capacitor voltage and a first axis component capacitor voltage. The load controller can be operable to regulate an active power supplied to the power grid by controlling the second axis component capacitor voltage and a reactive power supplied to the power grid by controlling the first axis component capacitor voltage, the load controller regulates the active power by altering a phase angle and a magnitude of the second axis component capacitor voltage of the capacitor voltage vector (VCAP).

Abstract: Techniques are described to continuously calculate an inverter DC power of a synchronous machine, e.g., motor or generator, based on the individual phase currents, DC link voltage, and gate signals, which can be compared against the commanded mechanical power based of the estimated rotor speed and commanded torque. A controller can determine whether to shut down the inverter, such as the pulse width modulation (PWM), if the DC power is greater than a threshold value. Such a threshold can be defined to allow an acceptable position and speed estimation error margin.

Abstract: Capacitor voltage balancing techniques are described for a 3-level 3-level dual-active-bridge converter that controls the duration of a zero voltage state of the low voltage (LV) and medium (MV) side transformer voltages based on a voltage difference between the upper and lower capacitors of both the LV and MV sides independently, the power delivered (P), and the LV and MV DC voltages. This control varies the angle to maintain the power requirement, which induces the additional voltage drop across the transformer inductance to produce the required current to flow through the capacitors and balance the capacitor voltages.

Abstract: Techniques to limit electrical power when forming an electrical grid using an active front end unit having an inverter that is coupled to a capacitor (and inductor) that is coupled to an electrical grid. For example, to limit power, the integration of a commanded frequency of the system can be limited to be within a specified phase delta of a measured phase angle of an electrical grid voltage vector. The calculation from power limit to phase delta can be done when the phase of the electrical grid voltage vector has been determined to be accurate and is calculated based on the measured capacitor voltage, grid voltage, and the estimated voltage drop across the output components of the system.

Abstract: An apparatus can include an inverter to provide an output N-phase alternating-current to an external component. When N equals two, a phase of the N phases can include an upper gate and a lower gate. The apparatus can also include a current detector configured to detect a phase current magnitude of the output alternating current. The apparatus can also include a controller coupled to the current detector and to the inverter. The controller can generate a gate command for controlling a gate of the inverter. The controller can also determine a value for a current threshold less than a shutoff current threshold for the external component. The controller can provide a protection command to turn off the upper gate of a corresponding phase of the inverter responsive to detecting that the phase current magnitude is greater than the current threshold.

Abstract: Techniques to limit electrical power when forming an electrical grid using an active front end unit having an inverter that is coupled to a capacitor (and inductor) that is coupled to an electrical grid. For example, to limit power, the integration of a commanded frequency of the system can be limited to be within a specified phase delta of a measured phase angle of an electrical grid voltage vector. The calculation from power limit to phase delta can be done when the phase of the electrical grid voltage vector has been determined to be accurate and is calculated based on the measured capacitor voltage, grid voltage, and the estimated voltage drop across the output components of the system.

Abstract: Techniques to reduce discontinuities in power, for example, by controlling an electrical power output of an active front end unit during a transition between a first operating mode and a second operating mode. In some examples, to reduce discontinuities, a control unit of the active front end unit can seed the integrator of proportional-integral (PI) controllers that are brought online during the operating mode change with a value that represents the proper state of the current system, such as the measured or calculated value of the component the PI controller is controlling). In other examples, to reduce discontinuities, a control unit of the active front end unit can control reference frame alignment during a transition between a first operating mode and a second operating mode.

Abstract: An apparatus can include an inverter to provide an output N-phase alternating-current to an external component. When N equals two, a phase of the N phases can include an upper gate and a lower gate. The apparatus can also include a current detector configured to detect a phase current magnitude of the output alternating current. The apparatus can also include a controller coupled to the current detector and to the inverter. The controller can generate a gate command for controlling a gate of the inverter. The controller can also determine a value for a current threshold less than a shutoff current threshold for the external component. The controller can provide a protection command to turn off the upper gate of a corresponding phase of the inverter responsive to detecting that the phase current magnitude is greater than the current threshold.

Abstract: A work machine includes a frame, a traction system supporting the frame, a power source mounted on the frame, a switched reluctance motor, an inverter configured to control power to the motor from a power source, and a controller. The controller is configured to receive a signal indicating a desired torque and determine if the desired torque is between an upper threshold and a lower threshold. If the desired torque is between the upper threshold and the lower threshold, pulse width modulation is used to produce a PWM adjusted torque command, and the motor is commanded based on the PWM adjusted torque command. The PWM adjusted torque command is configured to cycle between the upper threshold and the lower threshold to produce the desired torque.

Abstract: Power based self-sensing of a rotor position of an SR motor at mid to high speeds and low torque is achieved by an SR motor control system by comparing the motor power to an injection maximum power. A position current pulse is injected to a stator pole in response to the motor power being less than the injection maximum power. An actual stator current created by the position current pulse is compared to an estimated stator current, and a stored estimated rotor position in a memory is updated to a new estimated rotor position if the actual stator current is not equal to the estimated stator current.

Abstract: A system and method for torque compensation in a switched reluctance (SR) machine disposed on a machine is disclosed. The system may comprise a SR machine, an inverter and a controller. The controller is in operable communication with the inverter and is configured to determine a commanded main current associated with energization by a main current of a first portion of the plurality of windings for a controlling phase, and determine a commanded parasitic current associated with energization by a parasitic current of a second portion of the windings in a non-controlling phase. The controller is further configured to determine an offset current based on the commanded parasitic current, and determine a target current based on a first sum of the commanded main current and the offset current, and command the inverter to actuate the target current in the first portion of the windings during the controlling phase.

Abstract: Power based self-sensing of a rotor position of an SR motor at mid to high speeds and low torque is achieved by an SR motor control system by comparing the motor power to an injection maximum power. A position current pulse is injected to a stator pole in response to the motor power being less than the injection maximum power. An actual stator current created by the position current pulse is compared to an estimated stator current, and a stored estimated rotor position in a memory is updated to a new estimated rotor position if the actual stator current is not equal to the estimated stator current.