Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
  • H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
  • H02P21/24—Vector control not involving the use of rotor position or rotor speed sensors
  • H02P21/26—Rotor flux based control

Definitions

• the invention relates to the technical field control of electrical machines, and in particular, the control of asynchronous electrical machines.
• the asynchronous electric machine by its construction, is the most robust and cheapest electric machine on the market. Advances in the control of such machines and considerable technological advances, both in the field of power electronics and in microelectronics, have made it possible to install powerful controls for this machine, making it daunting competitor in the areas of variable speed and rapid torque control. However, many problems remain. The influence of variations in the parameters of the machine and the presence of mechanical sensors are all difficulties that have sharpened the curiosity of researchers and engineers.
• the electric angle sensor which makes it possible to know the position of the electric angle of the rotor of the machine is particularly expensive.
• the document US 2013 / 0289934A1 describes a method for estimating the flux of the stator from the signals of the voltage and currents of the machine, which is then used to estimate the rotor flux of the machine from the stator flux.
• the method also includes determining the electrical angle and its derivative.
• CN102437813 discloses a method for increasing the rotor angle and velocity from the rotor flux for a permanent magnet synchronous machine. Moreover, the teaching of the document implies an extensive use of the physical filtering through an extraction of the fundamental of the voltage and current of the rotor. Such a document is therefore irrelevant to the problem to be solved.
• the subject of the invention is a method for estimating the electric angle of an asynchronous electric machine for a motor vehicle, characterized in that it comprises the following steps:
• components of the estimated stator flux in the Clarke two-phase coordinate system are determined as a function of components of the estimated stator currents in said two-phase reference frame and components of the estimated rotor flux in said two-phase reference,
• estimated stator current components in said two-phase coordinate system are determined as a function of measured stator current components expressed in said two-phase coordinate system, said estimated stator flux components, stator supply voltages expressed in said two-phase reference and d a correction of the nonlinearities on the errors in stator currents in the form of gain, integral and second order filters.
• estimated rotor flux components are determined in the Clarke two-phase reference as a function of components of the estimated supply current of the rotor in said two-phase reference, and a correction of the nonlinearities on the stator current errors in the form of filters first and second order, and
• the estimated electric angle is determined as the arc tangent of the ratio of the two estimated rotor flux components expressed in the Clarke two-phase coordinate system.
• the correction of the nonlinearities can be determined as a function of the difference between the observed values and the setpoints of the stator and rotor supply currents in the Clarke two - phase reference, of the control parameters, the resistivity of the rotor, the inductance of the rotor, the mutual inductance between the rotor and the stator and the product of the mechanical speed of rotation by the number of pairs of poles of the machine.
• FIG. 1 illustrates the three-phase mark and the two-phase mark of
• FIG. 2 illustrates the various usual references in electrical control
• Clarke transformation rather than that of Concordia to change three-phase quantities (a, b, c) to two-phase magnitudes ( ⁇ , ⁇ ).
• Clarke's single-phase reference frame rotates like the stator voltages. It is therefore possible to measure the electrical angle in this rotating system.
• the inventors had the surprising idea of using machine control knowledge to simplify the model used.
• the stator voltages are controlled so as to obtain a zero rotor flux on the axis q of the machine, that is to say in the orthoradial direction to the magnetic axis of the rotor, which makes the control of the point efficient of performance.
• the rotor flux is oriented on the axis d, so as to obtain a zero value of the quadrature component of the flux, which is illustrated in FIG. 2.
• the Park benchmark is only mentioned here to explain the reasoning that led the inventors to design the rotor flux observer model.
• the observer obtained makes it possible to go directly from the three-phase reference point to the two-phase mark of Clarke.
• the difficulty lies in estimating flows. Indeed, it is known that the supply voltages of the electrical machine are not applied in a precise manner, which is due to the non-linearities of the inverter (converter). Given that the angle is determined by the measured currents and
• Equation 6 is determined iteratively using the previously estimated values of stator currents or rotor flux as well as values estimated at the current stage, in particular for the stator flows and the rotor current.
• a first step 1 the components of the rotor and stator power currents and voltages of the electric machine are determined in a Clarke two - phase reference as a function of the components of the rotor supply currents and voltages. stator in a three-phase reference. The components of currents accessible to the measurement are the stator components in the three-phase reference.
• the method is continued in a second step 2, during which the components of the stator flux in the Clarke diphasic reference are determined as a function of the components of the stator current and the components of the rotor flux in the stator. Clarke's two-phase benchmark.
• the stator flux is obtained as a function of the stator current and the rotor flux by applying the equation (Eq.4). This equation is applied to the values measured or estimated at the previous iteration when solving the equation (Eq.6).
• At the first iteration of the resolution of the equation Eq.6 one of course uses null initial values for certain values (in particular of flux).
• the rotor flux components in the Clarke two-phase coordinate system are determined as a function of the components of the rotor supply current in the Clarke two-phase reference and the components of the magnetic flux of the rotor in the second phase. Clarke's two-phase benchmark and a correction of the nonlinearities on the error components in stator currents in the Clarke coordinate system.
• This stage 3 also determines the estimated components of the stator current as a function of the supply voltage and the stator flux in the Clarke two-phase reference, and a correction of the non-linearities on the stator current error components. in Clarke's landmark.
• the rotor flux is obtained as a function in particular of the rotor current by applying the system of equations (Eq.6).
• step 4 the electrical angle is determined as the arctangent of the ratio between the two rotor flux components expressed in the Clarke two-phase reference.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Control Of Ac Motors In General (AREA)

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• 2014
  • 2014-04-30 FR FR1453935A patent/FR3020730B1/fr not_active Expired - Fee Related
• 2015
  • 2015-04-23 WO PCT/FR2015/051108 patent/WO2015166173A2/fr not_active Ceased
  • 2015-04-23 EP EP15723266.1A patent/EP3138193A2/de not_active Withdrawn

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