1.-10. (canceled)
11. A method for variation of a rated current which is specific for a motor, comprising the steps of:
providing a rated-current basic-value signal as a function of a rated-current basic value of the motor;
ascertaining an actual temperature;
generating a temperature signal in response to the actual temperature;
determining an actual rated current as a function of the rated-current basic-value signal and of the temperature signal; and
generating a rated-current signal in response to the actual rated current.
12. The method of claim 11, further comprising the step of ascertaining a temperature within a housing or a housing temperature of the motor as the actual temperature Tact.
13. The method of claim 11, wherein the rated-current basic value is defined for a specific rated-current temperature, and wherein the actual rated current is determined as a function of the rated-current temperature.
14. The method of claim 13, further comprising the step of determining the actual rated current on the basis of the rated-current basic value, the actual temperature, the rated-current temperature, a maximum permissible ambient temperature or a coolant temperature, and a correction factor for a temperature influence using
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15. The method of claim 11, wherein the rated-current basic value is matched to the actual rotation speed of the motor.
16. An apparatus for variation of a rated current which is specific for a motor, comprising:
an output device for providing a rated-current basic-value signal as a function of a rated-current basic value of the motor;
a sensor device for ascertaining an actual temperature and generating a corresponding temperature signal; and
an evaluation device having an input side which is coupled to an output of the output device and to an output of the sensor device, for supplying the rated-current basic-value signal and the temperature signal in order to determine an actual rated current as a function of the rated-current basic-value signal and the temperature signal and to provide a corresponding rated-current signal.
17. The apparatus of claim 16, wherein the output device is constructed to deliver a rated-current temperature which is associated with the rated-current basic value to the evaluation device via a rated-current temperature signal, and wherein the evaluation device is constructed to determine the actual rated current on the basis of the rated-current basic value, the actual temperature, the rated-current temperature, a maximum permissible ambient temperature or coolant temperature, and a correction factor for a temperature influence using
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18. The apparatus of claim 16, further comprising a rotation-speed recording device, which ascertains a rotation speed of the motor and provides a corresponding rotation-speed signal to the output device, wherein the output device is constructed to provide a rated-current basic-value signal, which is matched to the rotation-speed signal, to the evaluation device.
19. A measurement system for determination of the load level on a motor, comprising an apparatus which includes an output device for providing a rated-current basic-value signal as a function of a rated-current basic value of the motor, a sensor device for ascertaining an actual temperature and generating a corresponding temperature signal, and an evaluation device having an input side which is coupled to an output of the output device and to an output of the sensor device, for supplying the rated-current basic-value signal and the temperature signal in order to determine an actual rated current as a function of the rated-current basic-value signal and the temperature signal and to provide a corresponding rated-current signal.
20. A measurement system for temperature monitoring of a motor, comprising an apparatus which includes an output device for providing a rated-current basic-value signal as a function of a rated-current basic value of the motor, a sensor device for ascertaining an actual temperature and generating a corresponding temperature signal, and an evaluation device having an input side which is coupled to an output of the output device and to an output of the sensor device, for supplying the rated-current basic-value signal and the temperature signal in order to determine an actual rated current as a function of the rated-current basic-value signal and the temperature signal and to provide a corresponding rated-current signal.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A frequency generator, comprising:
a direct digital synthesizer having an accumulator for providing an interim output and a digital interpolator for interpolating the interim output to provide an output signal with reduced electromagnetic interference, wherein the digital interpolator comprises at least one converter among a digital-to-phase converter and a digital-to-time converter; and
a digitally programmable spreading function applied to an input of the direct digital synthesizer.
2. The frequency generator of claim 1, wherein the direct digital synthesizer is a ROM-less direct digital synthesizer.
3. The frequency generator of claim 1, wherein the accumulator produces the interim output at a frequency dependent upon an input word provided as an input to the direct digital synthesizer.
4. The frequency generator of claim 3, wherein the accumulator is a phase accumulator having a reference clock as a first input, a frequency control word modified by the spreading function as a second input, and a fed-back interim output as a third input.
5. The frequency generator of claim 1, wherein the digital interpolator further comprises a divider and a tapped logic delay line.
6. The frequency generator of claim 5, wherein the digital interpolator comprises a time domain interpolator having the digital-to-time converter and a delay-locked loop.
7. The frequency generator of claim 5, wherein the digital interpolator comprises a frequency domain interpolator having the digital-to-phase converter and a delay-locked loop.
8. The frequency generator of claim 7, wherein the digital interpolator further comprises a decoder coupled between the divider and a windowing function, a transmission gate array coupled between the windowing function and delay locked loop, and a RS Flip-Flop coupled to the transmission gate array.
9. The frequency generator of claim 1, wherein the frequency generator comprises a first spreading function, a first accumulator, and a first digital interpolator for generating rising edges of the output signal and a second spreading function, a second accumulator, and a second digital Interpolator for generating falling edges of the output signal, wherein the rising edges and the falling edges are independently phase shifted.
10. The frequency generator of claim 1, wherein the accumulator, the digital interpolator and the digitally programmable spreading function generates rising edges of the output signal and a phase offset summer further enables generation of falling edges of the output signal, wherein the rising edges and the falling edges are phase offset relative to each other.
11. The frequency generator of claim 2, wherein the frequency generator is implemented as an integrated digital CMOS circuit.
12. A frequency generator providing an output signal with reduced electromagnetic interference, comprising:
a ROM-less direct digital synthesizer; and
a digitally programmable spreading function applied to an input of the direct digital synthesizer, wherein the ROM-less direct digital synthesizer comprises a digital interpolator having a divider and a tapped logic delay line.
13. The frequency generator of claim 12, wherein the digital interpolator comprises a time domain interpolator having a digital-to-time converter and a delay-locked loop.
14. The frequency generator of claim 12, wherein the digital interpolator comprises a frequency domain interpolator having a digital-to-phase converter and a delay-locked loop.
15. The frequency generator of claim 12, wherein the digital interpolator further comprises a decoder coupled between the divider and a windowing function, a transmission gate array coupled between the windowing function and delay locked loop, and a RS Flip-Flop coupled to die transmission gate array.
16. The frequency generator of claim 12, wherein the frequency generator comprises a first spreading function, a first accumulator, and a first digital interpolator for generating rising edges of the output signal and a second spreading function, a second accumulator, and a second digital interpolator for generating falling edges of the output signal, wherein the rising edges and the falling edges are independently phase shifted.
17. The frequency generator of claim 12, wherein the ROM-less direct digital synthesizer comprises an accumulator and a digital interpolator which along with the digitally programmable spreading function generates rising edges of an output signal of the frequency generator and wherein a phase offset summer further enables generation of falling edges of the output signal, wherein the rising edges and the falling edges are phase offset relative to each other.
18. A method of mitigating electromagnetic interference, comprising the steps of:
modulating an input control word to provide a modulated input control word to on accumulator;
processing a residue from the accumulator by dividing the residue by the modulated input control word to provide a ratio indicating a delay between an edge of a system clock and a desired rising edge of an output signal; and
delaying the output signal by digitally interpolating the ratio using at least one among digital-to-phase conversion and digital-to-time conversion to provide the delay.
19. The method of claim 18, wherein the step of modulating comprises the step of applying a spreading function to the input control word.
20. The method of claim 18, wherein the step of processing further comprises the step of decoding and windowing the ratio.
21. The method of claim 18, wherein the method further comprises the step of independently phase shifting a plurality of rising and falling edges to control a duty cycle of the output signal.
22. A method of mitigating electromagnetic interference, comprising the steps of:
applying a spreading function to an input signal to provide a modulated signal;
in a ROM-less direct digital synthesizer:
accumulating the modulated signal to provide a residue;
dividing the residue by the input signal to provide a ratio; and
digitally interpolating the ratio.