The embodiment of the invention discloses a power conversion control method and device and relates to the field of variable frequency drive technology. According to the invention, an inductance voltage reference value is determined according to received input current, input voltage, phase current and a preset motor rotation speed reference value, and a q-axis voltage specified rate and a d-axis voltage specified rate are determined according to the phase current, the input current, the input voltage and bus voltage, and then a first pulse width modulation signal and a second pulse width modulation signal according to the inductance voltage reference value, the q-axis voltage specified rate and the d-axis voltage specified rate. Current of the front end of a DC bus capacitor is adjusted through the first pulse width modulation signal and voltage of a signal modulation motor is modulated through the second pulse width modulation signal, so that power balance is achieved between the frontend and the rear end of the DC bus capacitor and ripple current of the DC bus capacitor is reduced. At the same time, since the DC bus capacitor only needs to store comparatively small power, the DCbus capacitor can be replaced with a film capacitor having comparatively small capacity.

Power conversion control method and device

The invention provides a low-frequency vibration suppression method and apparatus, and relates to the technical field of variable frequency driving. According to the method and apparatus, according toa received phase current, a motor rotating speed practical value, a d-axis current and a q-axis current are calculated, a q-axis torque current given amount is calculated according to a received input voltage, a moment of inertia, the motor rotating speed practical value, the q-axis current and a preset motor rotating speed reference value, a q-axis voltage given amount and a d-axis voltage givenamount are determined according to the d-axis current, the q-axis current, the q-axis torque current given amount and a preset d-axis torque current given amount, and finally pulse width modulation signals are generated according to the q-axis voltage given amount and the d-axis voltage given amount to realize adjustment of the voltage input to a motor. Therefore, the output torque of the motor is rapidly controlled through the real-time operation state of the motor, uniform rotating speed of a motor rotor is ensured, the vibration of an air-conditioner compressor during low-frequency operation is reduced, the stability of air-conditioning system pipelines is improved, and the lifetime of the air-conditioning system pipelines is prolonged.

Low-frequency vibration suppression method and apparatus

The invention provides a current control method and device for a permanent magnet synchronous motor, and relates to the technical field of electrolytic capacitor-free variable frequency drive According to the method and the device, the q-axis torque current and the d-axis current reference value are determined according to received bus voltage, phase current input into a motor and the operating parameters of the motor; the actual speed control output limit is calculated according to the d-axis current reference value and a preset speed control output limit; the q-axis current reference valueis determined according to the q-axis torque current and the actual speed control output limit, so that the current control of the permanent magnet synchronous motor is realized; in the process of calculating the actual speed control output limit, field weakening current is introduced into feedback; in a field weakening state, the actual speed control output limit can be adjusted according to themagnitude of the field weakening current; the q-axis current reference value does not exceed the preset speed control output limit; and motor demagnetization caused by the increased field weakening current can be avoided

Current control method and device for permanent magnet synchronous motor

The invention provides a field weakening control method and a device and relates to the technical field of the electrolytic capacitor-free variable-frequency driving technology. According to the method and the device, based on an received input voltage, a bus voltage, a phase current, a d-axis voltage, a q-axis voltage, a preset bus voltage reference value and an average voltage margin set value,a fixed variable of a q-axis torque current and a fixed variable of a d-axis torque current are determined. After that, based on the phase current, the fixed variable of the q-axis torque current andthe fixed variable of the d-axis torque current, a fixed variable of a q-axis voltage and a fixed variable of a d-axis voltage are determined. Finally, according to the fixed variable of the q-axis voltage and the fixed variable of the d-axis voltage, a pulse width modulation signal is generated and a voltage input to a motor is adjusted. As a result, the outputted fixed variable of the d-axis torque current conforms to the difference between the voltage required by the motor and the maximum voltage outputted by an inverter when the direct-current bus voltage and the input voltage fluctuate over half of a peak value. Moreover, the motor has different weak magnetic depths during the peak and valley values of a direct-current bus voltage. The operation efficiency of the motor is improved.

Field weakening control method and device

An embodiment of the invention provides a DC bus voltage protection method and device, and relates to the technical field of variable frequency drive. The method and device are characterized by comparing a bus voltage and a preset bus voltage protection value, and determining torque current compensation amount according to the comparison result; then, determining q-axis voltage given amount and d-axis voltage given amount according to phase current, input voltage, a preset motor speed reference value, preset d-axis torque current given amount and the torque current compensation amount; and according to the q-axis voltage given amount and the d-axis voltage given amount, generating a pulse width modulated signal to adjust the voltage of the motor. Since the torque current compensation amount is associated with the bus voltage, when the bus voltage is too large, the q-axis voltage given amount can be adjusted in real time through the torque current compensation amount, the motor is allowed to quickly consume energy stored in a DC bus capacitor to reduce the DC bus voltage, a purpose of protection of the DC bus voltage is achieved, and circuit stability is improved.

DC bus voltage protection method and device

The embodiment of the invention provides a power conversion control device, and relates to the technical field of variable frequency driving. The power conversion control device calculates a q-axis voltage instruction value and a d-axis voltage instruction value according to power supply voltage, bus voltage, phase current inputted into a motor and a preset motor speed reference value received by a circuit parameter receiving unit through a q-axis voltage instruction value setting unit and a d-axis voltage instruction value setting unit, and a pulse width modulation unit generates a pulse width modulation signal according to the q-axis voltage instruction value and the d-axis voltage instruction value so as to control the motor to output high power at the AC voltage peak and control the motor to output small power near an AC voltage zero crossing point, so that the input current waveform is enabled to be small near the AC voltage zero crossing point, the current harmonic is reduced, the power factor is increased, and the work efficiency of the motor is enabled to be enhanced.

Power conversion control device

The embodiment of the invention provides a frequency conversion driving method and device, and relates to the technical field of frequency conversion driving According to the frequency conversion driving method and device, by collecting power supply input current, power input voltage, bus voltage and phase current input to a motor and other parameters, and according to the parameters, the position of a motor rotor is estimated and the given amount of q-axis voltage and the given amount of d-axis voltage are calculated; then according to the given amount of the q-axis voltage and the given amount of d-axis voltage, a voltage adjustment instruction is generated so that the three-phase voltage input to the motor can be adjusted in real time based on phase current and motor speed actual value so as to achieve the direct transformation from electrical network power and motor power; by controlling the power supply input current accurately, the control on power factors can be realized to make the motor operate stably

Frequency conversion driving method and device

The embodiment of the invention provides a frequency conversion driving system, and relates to the technical field of frequency conversion driving. According to the frequency conversion driving system, by collecting power supply input current, power input voltage, bus voltage and phase current input to a motor and other parameters, a pulse width modulation signal is generated based on the parameters; then a driving module controls the motor to operate according to the pulse width modulation signal, so that in the case of amplitude fluctuation of the bus voltage, the motor can still operate stably; at the same time, input power factor correction function can be achieved without using the traditional power factor correction circuit, so that ultimately an outer machine main board is smaller in volume, lighter in weight and loner in service life.

Frequency conversion driving system

An embodiment of the invention provides a frequency-variable driving control device, which relates to the field of frequency-variable driving technologies. The frequency-variable driving control device comprises a circuit parameter receiving module, a voltage setting module and a pulse width modulation module, wherein the circuit parameter receiving module acquires parameters such as a power supply input current, a power supply input voltage, a bus voltage and phase currents input to a motor, a q-axis voltage preset quantity and a d-axis voltage preset quantity are calculated according to the parameters by means of the voltage setting module, and the pulse width modulation module generates pulse width modulation signals according to the q-axis voltage preset quantity and the d-axis voltage preset quantity, thus, three-phase voltages output to the motor can be adjusted in real time according to the phase currents and the actual value of a motor rotation speed, so as to realize direct conversion from grid power to motor power; and the control of power factors can be realized through controlling the power supply input current precisely, thus the motor can operate stably.

Zhuo Senqing

Papers

Power conversion control device

Power conversion control method and device

Frequency conversion driving method and device

Frequency conversion driving system

Frequency-variable driving control device