Method for operating an electrical machine and electrical machine

Patent metadata

Field	Value
Publication number	US-10469017-B2
Application number	US-201815942935-A
Country	US
Kind code	B2
Filing date	Apr 2, 2018
Priority date	May 15, 2017
Publication date	Nov 5, 2019
Grant date	Nov 5, 2019

Abstract

A method for operating an electrical machine, wherein an inverter of the electrical machine is actuated by a pulse width modulation. In one case, it is provided that a pulse duty factor for the pulse width modulation is determined from a voltage value (d) that is dependent on the desired rotational speed as well as a time-dependent angle value (α). Embodiments of the invention further relate to an electrical machine.

First claim

The invention claimed is:

1. A method for operating an electrical machine, comprising:
an inverter of the electrical machine is actuated by a pulse width modulation, wherein a pulse duty factor for the pulse width modulation is determined from a voltage value (d) that is dependent on the desired rotational speed as well as a time-dependent angle value (α), so that the electrical machine is actuated by a voltage-oriented control (VOC),
wherein in that, in a summation of the angle value (α), as an additional summand, a difference between a first angle (γ) and a second angle (γ′) is used, wherein the first angle (γ) is determined from the desired rotational speed (ω) and the field attenuation value (φ) and the second angle (γ′) corresponds to the previous value of the first angle (γ) or is determined from measured phase currents (IU, IV) through the inverter.

2. The method according to claim 1 , wherein in that, as the voltage value (d), a ratio of a desired voltage (U) to an intermediate circuit voltage (Uz) is used, wherein the desired voltage (U) is determined from at least one characteristic value of the machine (c) as well as the desired rotational speed (ω).

3. The method according to claim 2 , wherein in that, in the determination of the desired voltage (U), a field attenuation value (φ) is additionally taken into account.

4. The method according to claim 1 , wherein in that the angle value (α) is summed up, wherein, as a summand, a product of the desired rotational speed (ω) and a time difference (Δt) is used.

5. The method according to claim 1 , wherein in that the phase currents (I U ,I V ) are converted by means of a Clarke transformation into a real part (x) and an imaginary part (y).

6. The method according to claim 1 , wherein in that, as the second angle (γ′), a difference between the angle value (α) and an angle (β), which is determined from the real part (x) and the imaginary part (y), is used.

7. The method according to claim 6 , wherein in that, from the angle (β), by means of the derivative with respect to time, an actual rotational speed (ω) is calculated, and/or in that, from the real part (x) and the imaginary part (y), an actual current intensity (I) and/or an actual current intensity gradient (dI/dt) is/are determined.

8. The method according to claim 1 , wherein in that, during a calibrating operation of the electrical machine, at least one machine-specific machine value (c, R, L) is determined.

Assignees

• Audi Ag

Inventors

• Maiwald Stefan

Classifications

• H02P21/18 Primary

  Estimation of position or speed · CPC title

• H02P21/22

  Current control, e.g. using a current control loop · CPC title

• H02P2203/09

  Motor speed determination based on the current and/or voltage without using a tachogenerator or a physical encoder · CPC title

• H02P23/14

  Estimation or adaptation of motor parameters, e.g. rotor time constant, flux, speed, current or voltage · CPC title

• H02P27/085 Primary

  wherein the PWM mode is adapted on the running conditions of the motor, e.g. the switching frequency · CPC title