1241 results about "Deadband" patented technology

Systems, methods, and apparatuses are disclosed for determining dead-times in switched-mode DC-DC converters with synchronous rectifiers or other complementary switching devices. In one embodiment, for example, a controller for a DC-DC converter determines dead-times for switching devices of a synchronous rectifier or other complementary switching device of the converter in which a dead-time is derived from an output voltage or current that is already sensed and used in the output regulation of the converter. In another embodiment, a controller is provided for controlling a switched-mode DC-DC converter comprising a pair of power switches. The controller comprises an input, a reference generator, a comparator, a compensator, a dead-time sub-controller, and a modulator. In another embodiment, the controller may adjust the dead-times during the operation of the converter to adjust periodically and/or in response to changes in operating conditions. In addition, methods of determining dead-times of control signals for a switched-mode DC-DC converter comprising a pair of power switches and of controlling a DC-DC converter are also disclosed.

A system for controlling a switching power converter and includes a digital controller that receives an analog signal representing the output DC voltage of the power converter for comparison to a desired output voltage level and generates switching control signals to control the operation of the power supply to regulate the output DC voltage to said desired output voltage level. At least two of the switching control signals having a dead time between a first edge of a first control signal and a second edge of a second control signal. The dead time is programmable such that the second edge of the second control signal may occur at a selected point in time either before or after the first edge of the first control signal.

A video encoder comprising an encoder circuit, a quantizer circuit and a control circuit. The encoder circuit may be configured to generate a number of coefficient values in response to a video stream and a number of quantized values. The quantizer circuit may be configured to generate the number of quantized values in response to the coefficient values, two or more quantization dead zones and two or more offsets. The control circuit may be configured to set the two or more quantization dead zones and the two or more offsets to different values. The two or more quantization dead zones and the two or more offsets are independently programmable.

An apparatus and method for controlling a steering command of a vehicle is provided. A deadband value based on a current state of a transporter is applied to a roll compensated steering command to control steering of the vehicle. A gain is applied to a steering command to control steering of the vehicle.

A power generation system including a photovoltaic (PV) module to generate DC power is provided. The system includes a combination of a DC to DC converter and a DC to AC converter coupled to the DC to DC converter for supplying power from the PV module to a power grid. The system further includes a bidirectional converter and an energy storage device coupled to the bidirectional converter. The system also includes a control system to generate commands for controlling a state of charge of the energy storage device. The control system comprises a deadband limiter to detect a deviation of the frequency signal outside of a respective signal range, a power shaper to provide a transient power generation adjustment signal in response to the signal being outside of the respective signal range and a limit controller for preventing the adjustment signal from causing the energy storage device to operate outside of at least one operating constraint.

A resonant switching power converter having adaptive dead time control provides improved efficiency along with reduced EMI/audible noise and component stresses. A dead time between pulses generated by a switching circuit is adaptively set in conformity with a value of the input voltage to the resonant switching power converter and an indication of a magnitude of the current passing through inductive element of the resonant tank of the converter. The indication of the current magnitude may be the switching frequency of the converter, or a measure of line or load current levels. The dead time can be obtained from a look-up table or computed from the current magnitude and input voltage values.

Disclosed is a dead-time compensation method of a 3-phase inverter using an SVPWM scheme. The dead-time compensation method includes generating a switching signal having dead-time with respect to the power semiconductor switches of the upper and lower arms in order to obtain a predetermined output through the SVPWM scheme, detecting medium phase current from each phase current output through the switching signal, determining polarity of the medium phase current, and generating a switching signal by calculating switching time in order to compensate for time to apply effective voltage according to the polarity of the medium phase current. Through the dead-time compensation method, the distortion of the output voltage and the reduction of voltage having a fundamental wave in the output voltage, which are caused by the dead-time, are minimized through the switching of compensating for the time to apply effective voltage based on the polarity of the load current.

An apparatus configured to detect transitions between relatively rising and falling amplitudes of an input signal Vin(t) arriving at a input node comprises a comparator having a first input, a second input, and an output for providing a two state output signal Vout(t) wherein state changes in the output signal Vout(t) correspond to the relatively rising amplitude of the input signal Vin(t) and the relatively falling amplitude of the input signal Vin(t). A delay circuit provides a shifted signal Vin(t+Δt) to the second input of the comparator, and a hysteresis circuit provides hysteretic deadband appended input signal Vin+ΔV to the first input of the comparator.

The invention discloses a primary frequency modulation electric quantity compensation refined control method and apparatus under a giant hydroelectric generating set power mode. The control method comprises the steps of obtaining a frequency difference signal between a power grid standard frequency and an actual power grid frequency obtained in real time; judging whether the frequency difference signal is outside a primary frequency modulation frequency dead zone or not, if the frequency difference signal exceeds the primary frequency modulation frequency dead zone, delaying for 0.1second and then outputting a primary frequency modulation action signal; using the frequency difference signal, and enabling a giant hydroelectric generating set speed regulator to be in a power mode; if the actual power grid frequency obtained in real time exceeds the primary frequency modulation frequency dead zone and is within in a range of a superposition value between the primary frequency modulation frequency dead zone and power dead zone equivalent power, performing superposition between a frequency compensation coefficient and the corresponding function of a frequency modulation load according to the frequency difference signal to obtain corresponding theoretical frequency modulation power; obtaining corresponding theoretical regulation power according to the frequency difference signal and the corresponding function of the frequency modulation load; and forming a PID closed loop by a new active given value and the actual power value of the giant hydroelectric generating set, and outputting a corresponding frequency modulation load instruction. By virtue of the primary frequency modulation electric quantity compensation refined control method and apparatus, the primary frequency modulation contribution rate of the giant hydroelectric generating set can be accurately controlled, the primary frequency modulation percent of pass is improved, and the electric energy quality can be improved.

A rotary-table servo system neural network control method comprises (1) building a mechanical dynamic model of a permanent magnet synchronous motor rotary-table servo system, and initializing the system state, sampling time and relative control parameters; (2) according to the differential mean value theorem, enabling a non-linear input dead zone in the system to linearly approximate to a simple time-varying system, avoiding complex calculation of dead-zone inverse compensation, and finally inferring a rotary-table servo system model provided with an unknown dead zone; (3) at each sampling moment, calculating and controlling a system tracking error, a fast terminal sliding mode surface and a first-order derivative of the system; (4) based on the rotary-table servo system model provided with the unknown dead zone, selecting a neural network approaching unknown trend, designing an adaptive robust finite-time neural network controller according to the system tracking error, the fast terminal sliding mode surface and the first-order derivative of the system, and updating a neural network weight matrix; and (5) entering the next sampling moment, and repetitively executing the steps from (3) to (5).

The invention relates to a frequency control strategy for a multiple DC (Direct Current) send-out island power grid. The frequency control strategy comprises the following steps of: 1, for the multiple DC send-out island power grid of which the system frequency is risen or reduced due to a fault, firstly, starting a first defense line and utilizing a DC system frequency limiting function to control the system frequency; 2, when the frequency exceeds a frequency operated dead zone of a dynamo governor, starting another measure in the first defense line, i.e. carrying out primary frequency modulation control by the dynamo governor; 3, when the frequency exceeds a range of 49.0 to 50.6Hz, starting a second defense line, i.e. cutting off a generator or a load according to a control strategy; 4, when the frequency exceeds 50.6Hz, starting a third defense line and carrying out high-frequency cut-off protection to cut off a generating set; 5, when the frequency exceeds 51.5Hz, enabling the generator to execute the overspeed protection action and cutting off the generating set. The frequency control strategy can be used as an actual control strategy for stabilizing the frequency of a large-scale multiple DC send-out island system to be applied to production and operation of the power grid and also can be applied to emulation calculation of related research.

A three-level inverter dead time compensation control method is used for compensating the decrease of system performance caused by dead time. According to the topological structure of a three-phase three-level PWM (pulse width modulation) inverter, the method first sets corresponding dead time and determines the on-off delays of power elements in the inverter; the method then considers the tube voltage drops of the power transistors of the inverter and the tube voltage drops of clamping diodes of the inverter and calculates the common voltage expression of the output neutral point of the inverter; afterwards, according to the sector with three-phase current value and a reference voltage vector, the method determines the relational coefficient between voltage error caused by the tube voltage drops of the power transistors, the tube voltage drops of the clamping diodes and the on-off delays of the power transistors and current, and thereby the total dead time compensation time of each phase of the three-level PWM inverter is worked out. The method takes the dead time, the on-off delays of the power elements and the tube voltage drops into full consideration, solves the problem of voltage and current distortion caused by the dead time effect in the three-level inverter, and enhances system performance.

In addition to an output voltage control loop, a dead-time optimization loop is provided for a digital synchronous switching converter to dynamically adjust the dead-time for the power switches of the converter. It is extracted a minimal feedback signal at a steady state while the output voltage remains under a specification, and a maximal efficiency of the digital synchronous switching converter is thus obtained.

A Synchronous PWM controller realized by dead-time modulation is provided for applying to the self-oscillation Royer inverter. The proposed dead-time-modulated PWM (DTM-PWM) controller is composed of a monostable circuit and a constant-current charger (CCC). The presented switching period for the buck regulation consists of a referred sawtooth having a constant-period and a dead-time. The synchronizing strategy is conducted by modulating the dead-time according to the resonant frequency of the Royer inverter. Two kinds of the control strategies in DTM-PWM controller are explored including the down-going and up-going error voltage controls. A DTM-PWM controlled dimmable Royer inverter with two-CCFL having primary-side control is designed and realized. Two kinds of the existing controllers for the Royer inverter are also experimented and compared with the proposed DTM-PWM controller. The results of the analysis and the theoretical prediction are verified with the experiments.