Variable-frequency drive

About: Variable-frequency drive is a research topic. Over the lifetime, 837 publications have been published within this topic receiving 5691 citations. The topic is also known as: VFD.

Dynamic reef surge generation

Abstract: Two apparatuses are disclosed for providing a dynamically varying water surge in a salt-water reef aquarium. The first apparatus is a micro-controller based variable frequency reef surge drive 100 for an AC permanent magnet synchronous motor (PMSM) submersible aquarium pump. Drive 100 comprises voltage conversion circuitry 105 , xmicro-controller 110 , reef-surge generation program 115 , variable frequency drive 118 , mode switch 130 and tidal cycle switch 135 . Three user-selectable modes of operation are provided: a random frequency mode, a fixed-program mode and a tidal mode. A second apparatus comprises a novel submersible AC PMSM pump with dual impeller assemblies and dual input and output chambers for supporting forward and reverse flow through an AC PMSM pump.

Power conversion control method and device

Abstract: 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.

Study on the application of permanent magnet synchronous motors in underground belt conveyors

Abstract: This paper analyzes and compares the advantages and disadvantages of several kinds of drive devices of belt conveyors from the angle of energy saving, and summarizes the application advantages and using problems of permanent magnet motor variable frequency drive system in belt conveyors. An example is given to demonstrate the energy saving effect of this system compared with other driving methods. This paper points out the application prospect of permanent magnet motor variable frequency drive system on belt conveyors and other large mining machines in coal mine. This paper is aimed to provide the design direction for the designer and the choice basis for the user on belt conveyor.

Multiple Systems Integration with Solar DC Micro-Off-Grid by using Energy-Efficient 3-phase VFD Inverter for Small Agro-Industrial Applications

Abstract: This paper presents multiple systems integration schemes with the solar micro-off-grid by using 3-phase variable frequency drive (VFD) inverters. The integrated system (IS) combines two crystalline photovoltaic (PV) arrays of 4.2kWp and 2.8kWp respectively. Considering small industrial applications, three distributed induction motor (IM) loads were installed i.e., two 3HP/2.2kW pumps and a 2HP/1.5kW motor. To minimize the power loss, an HV DC transmission line of350V was considered. The 3$-\varphi$ IM controllers ensure perturb and observation (P&O) maximum power point tracking (MPPT) operation to harness maximum power from the PV array. The 7kWp parallel system maintains an efficiency of over 90% from the PV array and the IGBT module based MPPT inverters keep running with an efficiency of 93%. The performance of the system is analyzed and verified using experimental data.

Vector control system, control method and device, air conditioner and storage medium

Abstract: The invention provides a vector control system, a control method and device, an air conditioner and a storage medium. The vector control system comprises a control module and a variable frequency drive module, wherein the control module comprises a weak magnetic current, a maximum torque current ratio control unit and an adjustment module; the variable frequency drive module receives an input pulse width modulation signal and is used for inverting the DC signal into a three-phase AC signal to input the signal in a permanent magnet synchronous motor, wherein the current output of the three-phase AC signal is increased by injecting the weak magnetic current so as to make the permanent magnet synchronous motor generate heat. The vector control system increases the current output of the three-phase AC signal by injecting a weak magnetic current into the permanent magnet synchronous motor such that the permanent magnet synchronous motor can generate heat, which realizes the function of low-temperature heating only needing to increase the weak magnetic current by means of software control with no need to modify the existing compressor structure. And the vector control system is applied to the outdoor unit of the air conditioner, which helps to reduce the production cost of the enterprise with a simple structure and is easy to implement.