Abstract:
A method of estimating the current flowing through a winding of a poly-phase electric load at a certain instant while keeping constant the duty-cycle of the PWM driving signals and without increasing relevantly the THD comprises the steps of imposing that between two consecutive edges of the control phases there is at least a certain minimum time, sufficient for measuring the current flowing through a DC_LINK line, but keeping symmetrical all control phases in respect to the instant of the cycle at which the current is to be determined. It is checked whether or not, in the switching cycle during which the current measurement is to be made, the edges of the control phases are sufficiently spaced one from the other. If not, switchings are purposely generated such that the control phases be always symmetrical in respect to the instant 0 or T/2, but with edges spaced one from the other by a certain minimum time.
Abstract:
A method of sensing the air/fuel ratio in a combustion chamber of an internal combustion engine that may be easily implemented by a respective low-cost device is disclosed. The device includes a pressure sensor and a learning machine that generates a sensing signal representing the air/fuel ratio by processing the waveform of the pressure in at least a cylinder of the engine. In practice, the learning machine extracts characteristic parameters of the waveform of the pressure and in function of a certain number of them generates the sensing signal.
Abstract:
A knocking presence evaluation circuit in an internal combustion engine having at least a pressure sensor (3) facing in combustion chamber for each cylinder comprised in the engine itself and suitable to detect a pressure signal ( Pr_Sign ). Advantageously, the circuit comprises:
a processing block (7), connected, in correspondence with an input terminal (IN4) of the knocking presence evaluation circuit (4), to the pressure sensor (3) and receiving therefrom the pressure signal ( Pr_Sign ), the processing block (7) performing a processing of the pressure signal ( Pr_Sign ) for insulating the oscillations and generating a derived pressure signal ( Fl_Pr_Sign ); an acquisition block (8), connected at input to the processing block (7) and receiving therefrom the derived pressure signal ( Fl_Pr_Sign ), the acquisition block (8) generating a first and a second measure signals ( Pul_Cnt, Pul_Dur ) respectively corresponding to a number and a total duration of digital pulses obtained from said derived pressure signal ( Fl_Pr_Sign ); and a soft-computing block (9) connected at input to the acquisition block (8) and receiving therefrom the first and second measure signals ( Pul_Cnt, Pul_Dur ) and connected to an output signal (OUT4) of the knocking presence evaluation circuit (4) to which the output terminal supplies a knocking intensity index ( Knock_index ), calculated by soft-computing techniques, starting from the first and second measure signals ( Pul_Cnt, Pul_Dur ).
A knocking identification and control system associated with an internal combustion engine and a processing method of a pressure signal for the detection and the evaluation of a combustion phenomenon in an internal combustion engine are also described.
Abstract:
An arrangement for controlling a system (S) according to the deviation (ERR) between the value measured on the system (VR) and the value (VS) estimated by means of a model of the controlled system (S) of at least one control parameter. The arrangement comprises a neural network (12), which generates the estimation (VS) of the control parameter according to a set of characteristic parameters (I, Q, T) of the controlled system (S) and of respective configuration parameters (W, B). The neural network (12) has associated thereto a training module (11), which can train said neural network (12) by modifying said configuration parameters (W, B) according to a set of updating data (I t , T t , Q t , V t ). An acquisition module (21, 221) acquires the actual value, as measured on the controlled system (S), of a set of sensing parameters comprising at least one from among said control parameter (VR) and said characteristic parameters (I, Q, T) of the controlled system. A variation module (22) is sensitive to the variation of said control parameter (V k , a ; V k , m ) and generates an update-enable signal (EU) when the control parameter falls outside a pre-set tolerance range (228). The acquisition module (21, 221) being sensitive to said update-enable signal (EU) for transferring to the training module (11), as updating-data set, said set of sensing parameters (V t , Q t , I t , T t ). A preferential application is for the control of fuel-cell stacks.
Abstract:
A probabilistic neural network, comprising a hidden layer of neurons, each computing respective membership matrix elements for an input vector of the neural network according to a respective radial basis function defined by a respective spread factor and according to the distance of the input vector from a respective constant vector, wherein said hidden layer comprises at least two neurons having different spread factors (S). A method of training the novel probabilistic neural network is also disclosed.
Abstract:
A method, implemented by circuital means in a device, for estimating at a certain instant two currents of a poly-phase electric load controlled in SVM mode, for example a three-phase electric motor, using the same measuring instrument, without introducing in the measurement error contributory terms due to the inevitable time lag between the two measurements carried out at different instants, comprises the steps of measuring the current flowing in one of the two windings exactly at the desired instant, measuring the current flowing in the other winding first with a certain anticipation in respect to the desired instant and after with a delay equal to the anticipation in respect to the desired instant. The estimated value of the current in the second winding is given in first approximation by the arithmetic mean of the two measured values before and after the desired instant of simultaneous measurement of the two currents. Therefore, the two currents can be measured with an undecremented precision using the same A/D converter connected through a multiplexer by performing the three closely sequenced sensing of electric current.