CN-121983466-A - Energy-saving control circuit and control method for electromagnetic coil current

CN121983466ACN 121983466 ACN121983466 ACN 121983466ACN-121983466-A

Abstract

The application belongs to the technical field of electromagnetic coil current control, and provides an energy-saving control circuit and a control method of electromagnetic coil current, the self-adaptive control of the coil excitation duty ratio is realized by sampling and controlling the frequency of the oscillator and the algorithm through the real-time VIN, the scheme is simple to realize, the cost is low, the volume of the contactor can be reduced, and the electromagnetic noise of the alternating-current contactor is reduced. In addition, the algorithm is adopted to control the slow change of the reference voltage of the comparator, so that the slow start of the electromagnetic coil current and the stable switching of the attraction and the holding are realized, the electromagnetic contactor is ensured to be capable of being attracted stably in the whole working process, some side effects are reduced, the dynamic performance of the contactor is improved, and the service life is prolonged.

Inventors

ZHAO YAJUAN
GENG WEISHENG
DUAN NING

Assignees

广州博之源科技有限公司

Dates

Publication Date: 20260505
Application Date: 20251231

Claims (10)

1. An energy-saving control circuit of electromagnetic coil current is characterized by comprising a contactor sampling unit, an input sampling unit and a functional circuit unit; the contactor sampling unit is used for collecting coil current sampling signals of a contactor coil, and the input sampling unit is used for collecting sampling filtering signals of an input end; the functional circuit unit comprises a coil current sampling circuit, a clock generating circuit, a threshold generating circuit, a comparator, a VS control duty cycle generating circuit and a control logic circuit; The coil current sampling circuit is connected with the contactor sampling unit, receives the coil current sampling signal, performs filtering and leading edge blanking processing, and outputs an optimized sampling signal; the threshold generating circuit is connected with the clock generating circuit, receives the clock signal and outputs a reference voltage signal which changes with time segments; the comparator is respectively connected with the coil current sampling circuit and the threshold generating circuit, receives the optimized sampling signal and the reference voltage signal, and outputs a pulse signal controlled by peak current after voltage comparison; the VS control duty ratio generating circuit is connected with the input sampling unit, receives the sampling filter signal and outputs a duty ratio control signal which adaptively changes along with the sampling filter signal; the control logic circuit is respectively connected with the comparator and the VS control duty ratio generating circuit, receives the pulse signal, the duty ratio control signal and the duty ratio selection control signal, and outputs the control signal through logic selection.
2. The energy-saving control circuit of the electromagnetic coil current according to claim 1, further comprising a power driving unit, wherein the power driving unit comprises a power switch upper tube and a power switch lower tube; One end of the power switch upper tube is connected with a contactor voltage input end, and the other end of the power switch upper tube is connected with the contactor coil; one end of the power switch lower tube is connected with the contactor coil, the other end of the power switch lower tube is grounded, and the control end of the power switch lower tube is connected with the output port of the control logic circuit to control the on-off time length of the power switch lower tube.
3. The energy-saving control circuit of the electromagnetic coil current according to claim 2, further comprising a protection unit, wherein the protection unit comprises a freewheeling diode and a quick turn-off module; The freewheeling diode is connected in parallel with two ends of the contactor coil and is used for realizing bus recharging of coil current when the system is normally powered off; the output end of the quick turn-off module is connected with the control end of the power switch upper tube, and when abnormality is detected, the output end of the quick turn-off module is connected with the control end of the power switch upper tube, and after the power switch lower tube is turned off, the power switch upper tube is controlled to enter a subthreshold region quickly in a delay mode, so that coil demagnetization turn-off is realized.
4. The energy saving control circuit of solenoid current of claim 3 wherein the VS control duty cycle generation circuit comprises a clock vco generation circuit and a duty module; the signal input end of the duty module is connected with the output end of the clock vco generating circuit, receives the vco signal, samples a plurality of vco clock cycles and calculates the average value, and combining the duty ratio corresponding to the maximum value or the minimum value of the sampling filter signal in the register configuration, determining the slope of the duty ratio by adopting a two-point method, and outputting a duty ratio control signal which adaptively changes along with the sampling filter signal.
5. A method of energy efficient control of solenoid current, for implementing the solenoid current energy efficient control circuit of claim 3 or 4, the method comprising the steps of: S1, switching in an electromagnetic coil current control circuit to input voltage, and keeping an upper power switch tube normally open after initialization, wherein a lower power switch tube is in a periodic switch state to be triggered; s2, synchronously acquiring a two-way signal and a clock signal, sampling a current signal of a contactor coil through a peripheral sampling resistor to obtain a coil current sampling signal of an original coil, performing partial pressure sampling on the voltage of an input end through a voltage dividing resistor, and filtering to obtain a sampling filtering signal of the input end; S3, inputting the coil current sampling signals obtained in the step S2 into a coil sampling circuit, eliminating high-frequency noise through RC filtering in sequence, and then shielding current peaks at the moment of opening a lower tube of a power switch through leading edge blanking to output stable optimized sampling signals; S4, inputting the clock signal obtained in the S2 into a threshold generating circuit, configuring the duration of each working stage of power-on soft start, stable suction, switching suction, stable suction and switching off by the timing of the clock signal, and outputting a reference voltage signal which changes with time in a sectional manner through a DAC; S5, inputting the optimized sampling signal obtained in the S3 and the reference voltage signal obtained in the S4 into a comparator, performing real-time voltage comparison, and outputting a pulse signal for peak current control; S6, inputting the sampling filter signal obtained in the S2 into a VS control duty ratio generating circuit to generate a duty ratio control signal which is adaptively matched with the sampling filter signal; And S7, selecting a target control signal from the pulse signal obtained in the step 5 and the duty ratio control signal obtained in the step 6 by the control logic circuit according to the duty ratio control signal and the mode control signal, transmitting the target control signal to the power switch lower tube through the output port, controlling the conduction time of the power switch lower tube, and realizing the staged adaptive control of the coil current.
6. The method for energy-saving control of a solenoid current according to claim 5, wherein in S3, the RC filter process is implemented by a filter circuit composed of a filter resistor and a filter capacitor; The front-edge blanking is realized by a front-edge blanking circuit consisting of RISE DELAY modules and NM0 tubes, the front-edge blanking time is generated by charging and discharging constant-current source capacitors of RISE DELAY modules, and after the front-edge blanking time is finished, the optimized sampling signal rises to a stable voltage and is equal to the coil current sampling signal in amplitude.
7. The method for controlling power saving of electromagnetic coil current according to claim 5, wherein in S4, the sectional change rule of the reference voltage signal is that the power-on soft start-up-pull-in stable stage is gradually stepped from 0 to the pull-in stable voltage value, the pull-in switching-on holding stage is uniformly changed according to preset step value and step time, and the holding stable stage maintains a constant voltage value.
8. The method of claim 5, wherein in S5, the comparator employs a two-stage architecture, the first stage increases gain and bandwidth by resistive bias, and the second stage further increases gain by OTA architecture; The voltage comparison logic is that when the optimized sampling signal is larger than the reference voltage signal, the pulse signal controlled by the peak current is turned to be high level, the power switch lower tube is controlled to be turned off, the coil current is reduced, and when the optimized sampling signal is smaller than the reference voltage signal, the pulse signal controlled by the peak current is turned to be low level, and the next period is waited to trigger and be conducted.
9. The method of claim 5, wherein in S6, the generating the duty control signal includes: S61, a clock vco generating circuit in a VS control duty ratio generating circuit charges and discharges a capacitor through a constant current source and generates a clock signal vco by combining a comparator, wherein when the duty ratio control signal is 1, the in-phase input level of the comparator is equal to a sampling filter signal, and the clock period of the vco is positively related to the sampling filter signal; s62, continuously sampling a plurality of vco clock cycles through a vco control duty module, calculating an average value, combining a maximum value or a minimum value of a sampling filter signal configured by a register with a corresponding duty ratio, and determining a duty ratio slope by adopting a two-point method; S63, according to the average value and the duty ratio slope, a duty ratio control signal is obtained through calculation, and the duty ratio control signal and the sampling filtering signal are in inverse proportion.
10. The method of claim 5, wherein in S7, the signal selection logic of the control logic circuit is: When the duty ratio selection control signal is at a low level, the duty ratio control signal is at a fixed maximum duty ratio, the rising edge of the pulse signal controlled by the peak current controls the gating signal of the chip to turn down, and the falling edge of the output signal of the output port is cooperatively controlled by the gating signal of the chip and the low level of the duty ratio control signal; When the duty ratio selection control signal and the mode control signal are enabled to be high level at the same time, the chip gating signal keeps constant high level, the falling edge of the output signal of the output port is independently controlled by the low level of the duty ratio control signal, and the system is separated from the peak current control mode.

Description

Energy-saving control circuit and control method for electromagnetic coil current Technical Field The application belongs to the technical field of electromagnetic coil current control, and particularly relates to an energy-saving control circuit and method for electromagnetic coil current. Background The electromagnetic contactor is used as a core electrical component for remotely and frequently controlling the on-off of a main circuit, is rapidly iterated around three directions of high efficiency, energy conservation, intellectualization and specific scene adaptation, and is widely applied to the emerging fields of new energy automobiles, smart power grids and the like. The working principle of the electromagnetic valve is that the magnetic field is generated by electrifying the coil to attract the armature, so that the main contact is closed, and the circuit is reset and disconnected by means of the spring after the power is off, so that the energy-saving thought of 'attracting instantaneous large current and small current after stabilization' is universally adopted in the prior art in order to respond to the severe energy consumption requirement of the market, and the technical bottleneck of the core technology is still faced. When the AC contactor works, the coil alternating current can make the iron core alternately magnetized, so that hysteresis loss and eddy current loss are caused, a large amount of energy is wasted, the iron core seriously heats, vibration and electromagnetic noise can be generated, the service life and the operation stability of equipment are affected, and the existing energy-saving scheme can not fundamentally solve the loss problem and has obvious defects. The existing energy-saving scheme can realize current switching by additionally arranging an auxiliary contact as a change-over switch in a starting and holding stage, but needs to additionally change and adjust the structure of the contactor, so that great inconvenience is brought to installation and maintenance, the universality is poor, and the control of duty ratio switching is realized by matching a plurality of peripheral devices on the basis of a singlechip, so that the circuit structure is complex, the redundancy of the components is caused, the product cost is greatly increased, the control reliability is easily reduced due to the cooperative work of the devices, and the requirements of the emerging field on equipment miniaturization and high stability are difficult to adapt. In summary, the prior art cannot simultaneously satisfy the comprehensive requirements of 'suppressing hysteresis and eddy current loss, reducing energy consumption', and 'simple structure, controllable cost, convenient use and high reliability', and restricts the further application of the electromagnetic contactor in the emerging field. Disclosure of Invention The application provides an energy-saving control circuit and a control method for electromagnetic coil current, which aims at solving the problems of complex circuit, high cost and poor use convenience in the existing energy-saving control technology aiming at hysteresis loss and eddy current loss in the holding stage of an alternating current contactor and causing the waste of heat energy generated by an iron core. In one aspect, an energy-saving control circuit for electromagnetic coil current is provided, comprising a contactor sampling unit, an input sampling unit and a functional circuit unit. The contactor sampling unit is used for collecting coil current sampling signals of a contactor coil, the input sampling unit is used for collecting sampling filtering signals of an input end, the functional circuit unit comprises a coil current sampling circuit, a clock generating circuit, a threshold generating circuit, a comparator, a VS control duty ratio generating circuit and a control logic circuit, the coil current sampling circuit is connected with the contactor sampling unit and used for receiving the coil current sampling signals and conducting filtering and leading edge blanking processing to output optimized sampling signals, the clock generating circuit is used for generating clock signals, the threshold generating circuit is connected with the clock generating circuit and used for receiving the clock signals and outputting reference voltage signals which change in a segmented mode along with time, the comparator is respectively connected with the coil current sampling circuit and the threshold generating circuit and used for receiving the optimized sampling signals and the reference voltage signals and outputting pulse signals controlled by peak current after voltage comparison, the VS control duty ratio generating circuit is connected with the input sampling unit and used for receiving the sampling filtering signals and outputting duty ratio control signals which change along with the sampling filtering signals in a self-adaption mode, and the control logic circuit is respect