CN203057040U - Discrete frequency-conversion soft starting device with no speed sensor - Google Patents
Discrete frequency-conversion soft starting device with no speed sensor Download PDFInfo
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- CN203057040U CN203057040U CN 201220717338 CN201220717338U CN203057040U CN 203057040 U CN203057040 U CN 203057040U CN 201220717338 CN201220717338 CN 201220717338 CN 201220717338 U CN201220717338 U CN 201220717338U CN 203057040 U CN203057040 U CN 203057040U
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Abstract
The utility model discloses a discrete frequency-conversion soft starting device with no speed sensor, which adopts a main loop structure for soft starting of a conventional thyristor as the main loop. A voltage synchronous signal acquisition circuit and a voltage sampling circuit inside a main loop control circuit are respectively connected between a main loop power supply input end and a DSC controller. A current sampling circuit and a current zero cross detection circuit are respectively connected between a main loop power supply output end and the DSC controller. A high-frequency constant-current triggering unit is connected between the control end of each thyristor in the main loop and the DSC controller. The device makes the starting impact and the starting current reduced and further increases the starting torque. A motor is enabled to be smoothly started when bearing a heavy duty or a full load. The discrete frequency-conversion soft starting device adopts the main loop structure for soft starting of the conventional thyristor and only changes the thyristor triggering control method. The cost is thus not increased while the discrete frequency-conversion soft starting device has greater performances than a conventional device adopting the conventional thyristor soft starting method. The device provided by the utility model thus achieves a soft starting function similar to that of a frequency converter.
Description
Technical field
The utility model belongs to the motor starting technical field, is specifically related to the discrete variable frequency soft start device of a kind of induction alternating current (AC) motor, is a kind of soft starter device of particularly suitable electromotor heavy load starting.
Background technology
Soft starter be the soft start of a kind of current collection machine, soft stop, light-load energy saving and kinds of protect function in the novel starting device of motor of one, be called Soft Statrer abroad.At present, the induction alternating current (AC) motor soft starter device has autotransformer, water resistance, controlled reactor, magnetic saturation reactor, solid-state soft starter, frequency converter etc.Frequency converter more is to be used in the speed governing occasion, and cost is than higher and control is complicated, for do not need speed governing and Fraquent start occasion, obviously cost performance is too low.The solid-state soft starter control performance is best, use the most general, replaced traditional soft starter device gradually, it is according to the thyristor voltage regulation principle, by regulating the triggering angle of thyristor, control its ON time, output voltage is extremely risen greatly gradually by little, up to supply voltage, thereby reduced the impact of starting current.Yet a very big shortcoming of reduced voltage starting is falling of starting electromagnetic torque.Square being directly proportional of the starting torque of motor and added stator side terminal voltage reduces voltage and will seriously reduce starting torque, makes motor band heavy-load start difficulty.So it is reduced voltage starting only is fit to unloaded rising or light start, also inapplicable for the motor of needs heavy duty or full load starting.In actual applications, motor is that requirement can be with heavy duty even full load starting greatly, as crane, pulverizer, ball mill, belt conveyor etc., in this case, adopt the across-the-line starting mode can produce very big harm: a, manufacturing machine is impacted; B, can cause excessive starting current to the impact of electrical network; C, not controlled starting can cause the high capacity motor starting failure when overload or low-voltage.
The utility model content
The purpose of this utility model is to provide a kind of and progressively improves in the voltage in starting process, correspondingly frequency is risen to mains frequency from low to high, improve the discrete variable frequency soft start device of starting torque, reduction starting current, introduce Speedless sensor simultaneously, it is level and smooth to guarantee that each frequency-division section switches, and starting steadily.
A kind of discrete variable frequency soft start device of Speedless sensor, comprise the threephase potential transformer that is connected between power supply and the motor, the three-phase anti-parallel thyristor, major loop and major loop control circuit that threephase current transformer constitutes, described major loop adopts the major loop structure of traditional thyristor soft start; Described major loop control circuit comprises voltage synchronous signal acquisition circuit, voltage sampling circuit, high frequency constant current trigger element, current over-zero testing circuit, DSC controller, current sampling circuit; Wherein said voltage synchronous signal acquisition circuit, described voltage sampling circuit are connected between described main circuit power input and the described DSC controller, and described current sampling circuit, described current over-zero testing circuit are connected between described main circuit power output and the described DSC controller; Described high frequency constant current trigger element is connected between each thyristor control end of described major loop and the described DSC controller.
The beneficial effects of the utility model: the discrete variable frequency soft start mode that this device has provided a kind of practicality solves the problem that the thyristor soft start can not realize the three phase squirrel cage induction motor heavy-load start.Realized real level and smooth raising frequency soft start, reduced starting-impact and starting current, improved a torque, can make motor at heavy duty or fully loaded smooth starting down.Because discrete variable frequency soft start adopts the major loop structure of traditional thyristor soft start, only changed the control method that thyristor triggers, so cost does not increase, yet obviously is better than traditional thyristor soft start on performance, has realized being similar to the soft starting characteristic of frequency converter.
Description of drawings
Fig. 1 is system configuration schematic diagram of the present utility model;
Fig. 2 is voltage synchronous signal acquisition circuit theory diagrams of the present utility model;
Fig. 3 is voltage sampling circuit schematic diagram of the present utility model;
Fig. 4 is current sampling circuit schematic diagram of the present utility model;
Fig. 5 is current over-zero testing circuit schematic diagram of the present utility model.
Embodiment
Below in conjunction with the drawings and specific embodiments the utility model is described in further detail.
The discrete variable frequency soft start device of the utility model Speedless sensor comprises the threephase potential transformer 1 that is connected between power supply and the motor, three-phase anti-parallel thyristor 2, major loop and major loop control circuit that threephase current transformer 3 constitutes; The major loop control circuit is by DSC controller 9, voltage synchronous signal acquisition circuit 7, current over-zero testing circuit 6, voltage sampling circuit 8, current sampling circuit 10 and high frequency constant current trigger element 5; Wherein voltage synchronous signal acquisition circuit 7, voltage sampling circuit 8 are connected between main circuit power input and the DSC controller 9, and current sampling circuit 10, current over-zero testing circuit 6 are connected between main circuit power output and the DSC controller 9; High frequency constant current trigger element 5 is connected between each thyristor control end of major loop and the DSC controller 9.
Current over-zero testing circuit 6 is made of voltage transformer, diode bridge rectifier circuit and isolation optocoupler.
The comparison circuit that amplifying circuit, comparator and the peripheral component that voltage synchronous signal acquisition circuit 7 is made up of voltage transformer, secondary amplifier chip and peripheral component formed, with door, Schmidt trigger constitutes.
The amplifying circuit that voltage sampling circuit 8 is made up of voltage transformer, secondary amplifier chip and peripheral component constitutes.
Amplifying circuit, diode, electric capacity, resistance that current sampling circuit 10 is made up of current transformer, secondary amplifier chip and peripheral component constitute.
Frequency conversion mode in the discrete variable frequency soft start device of a kind of Speedless sensor described in the utility model is to carry out frequency range according to the mode of f/N to divide, wherein f is mains frequency, mains frequency is 50HZ, theoretical N desirable 1,2,3...50 natural number, chosen 50HZ (N=1) in the utility model, 25HZ (N=2), 16.7HZ (N=3), 12.5HZ (N=4), 7.14HZ (N=7), 5HZ (N=10), seven frequency ranges of 3.85HZ (N=13) are finished discrete varying frequency starting mode, and the voltage regulating mode in the utility model is to carry out chopper control control according to the wave head number that current frequency comprises, guarantee the maximization of each frequency-division section torque, and by detecting the variation at electric machine phase current and afterflow angle, guarantee that motor near the rated speed of each frequency range the time, switches to next frequency range.
Embodiment 1: in conjunction with Fig. 1, the discrete variable frequency soft start device of the utility model Speedless sensor comprises by motor 4, threephase potential transformer 1, three-phase anti-parallel thyristor 2, threephase current transformer 3, voltage synchronous signal acquisition circuit 7, voltage sampling circuit 8, high frequency constant current trigger element 5, current over-zero testing circuit 6, DSC controller 9, current sampling circuit 10, LCD 11, single-chip microcomputer 12, keyboard 13.
Three-phase alternating current through through threephase potential transformer 1 respectively with three inputs of three-phase anti-parallel thyristor 2, voltage synchronous signal acquisition circuit 7, voltage sampling circuit 8 is connected, three outputs of three-phase anti-parallel thyristor 2 are connected with three inputs of motor 4 respectively by threephase current transformer 3, the signal output part of voltage synchronous signal acquisition circuit 7 connects a voltage signal zero passage detection input of DSC controller 9, another voltage signal that the signal output part of voltage sampling circuit 8 connects DSC controller 9 detects input, the signal output part of current over-zero testing circuit 6 connects a current signal zero passage detection input of DSC controller 9, another current signal that the signal output part of current sampling circuit 10 connects DSC controller 9 detects input, the control signal output of DSC controller 9 connects the signal input part of high frequency constant current trigger element 5, the signal output part of high frequency constant current trigger element 5 connects the control signal input of three-phase anti-parallel thyristor 2, the data input/output terminal of DSC controller 9 connects the data I/O of single-chip microcomputer 12, the demonstration signal output part of single-chip microcomputer 12 connects the signal input part of LCD 11, and the signal output part of keyboard 13 connects the signal input part of single-chip microcomputer 12.
Embodiment 2: in conjunction with Fig. 2-Fig. 5, the utility model mainly comprises major loop and major loop control circuit, major loop is made of threephase potential transformer 1, three-phase anti-parallel thyristor 2, threephase current transformer 3, realizes changing voltage and the frequency that is carried in motor side by the conducting of controlling the bidirectional thyristor in the major loop.The major loop control circuit comprises voltage synchronous signal acquisition circuit 7, voltage sampling circuit 8, high frequency constant current trigger element 5, current over-zero testing circuit 6, DSC controller 9, current sampling circuit 10.As shown in Figure 2, voltage synchronous signal acquisition circuit is nursed one's health into square-wave signal with the voltage transformer secondary side AC signal, as the benchmark in each frequency division cycle of trigger impulse correspondence constantly; As shown in Figure 3, voltage sampling circuit is gathered voltage transformer secondary side output voltage signal conditioning to 0～5V confession DSC controller; As shown in Figure 4, current sampling circuit is gathered Current Transformer Secondary side output signal conditioning to 0～5V confession DSC controller; As shown in Figure 5, the current over-zero testing circuit is by detection thyristor Voltage Drop Signals on SCR, and by voltage transformer, bridge rectifier and isolation optocoupler, the square-wave signal of output certain frequency.9 outputs of DSC controller drive control impuls, the amplitude size that voltage sampling circuit 8 is followed the tracks of input voltage, current sampling circuit tracking means output current size, voltage synchronous signal acquisition circuit 7 provides the benchmark that the drives control impuls moment, current over-zero testing circuit 6 provides the output current zero passage constantly, high frequency constant current trigger element 5 is controlled thyristor according to the driving control impuls of DSC controller 9, discrete like this variable frequency soft start device is according to the voltage sample value, current sampling data, the exact value that current zero-crossing signal and voltage synchronizing signal relatively draw motor afterflow angle is coordinated the discrete frequency range of control and is taken over seamlessly with the output current effective value and reach little starting current, the varying frequency starting effect of high starting torque.
Embodiment 3: the utility model adopts the major loop structure of traditional thyristor, and by the trigger sequence of rational control three-phase thyristor, the also frequency of suitable adjusting alternating current in regulation voltage realizes the control of discrete frequency conversion.Be that discrete frequency is progressively promoted in the starting process, reach consistent up to same mains frequency (50HZ), then realized discrete variable frequency soft start.Be break-make by thyristor-controlled alternating current processed with the method for three phase sine alternating current frequency conversion, the alternating current in n cycle is merged into one-period.The utility model is 7 grades of variable frequency soft starts, frequency is by 0HZ-3.85HZ-5HZ-7.14HZ-12.5HZ-16.7HZ-25HZ-50HZ, be divided into seven stages, phase I, the DSC controller sends f/13 and triggers the driving signal, in per 26 half-waves of power supply, remove wherein 13 half-waves according to the optimum way that calculates, and to remaining 13 half-wave chopper controls, making the voltage fundamental frequency that is added on the motor is 1/13 of power frequency, be 3.85HZ, by the sampling of current signal and afterflow angle signal, coordinate to switch to when the control motor speed approaches rated speed that should frequency range next frequency range.Second stage, the DSC controller sends f/10 and triggers the driving signal, in per 20 half-waves of power supply, remove wherein 10 half-waves according to the optimum way that calculates, and to remaining 10 half-wave chopper controls, making the voltage fundamental frequency that is added on the motor is 1/10 of power frequency, i.e. 5HZ, by the sampling of current signal and afterflow angle signal, coordinate to switch to when the control motor speed approaches rated speed that should frequency range next frequency range.Phase III, the DSC controller sends f/7 and triggers the driving signal, in per 14 half-waves of power supply, remove wherein 7 half-waves according to the optimum way that calculates, and to remaining 7 half-wave chopper controls, making the voltage fundamental frequency that is added on the motor is 1/7 of power frequency, i.e. 7.14HZ, by the sampling of current signal and afterflow angle signal, coordinate to switch to when the control motor speed approaches rated speed that should frequency range next frequency range.The quadravalence section, the DSC controller sends f/4 and triggers the driving signal, in per 8 half-waves of power supply, remove wherein 4 half-waves according to the optimum way that calculates, and to remaining 4 half-wave chopper controls, making the voltage fundamental frequency that is added on the motor is 1/4 of power frequency, i.e. 12.5HZ, by the sampling of current signal and afterflow angle signal, coordinate to switch to when the control motor speed approaches rated speed that should frequency range next frequency range.Five-stage, the DSC controller sends f/3 and triggers the driving signal, in per 6 half-waves of power supply, remove wherein 3 half-waves according to the optimum way that calculates, and to remaining 3 half-wave chopper controls, making the voltage fundamental frequency that is added on the motor is 1/3 of power frequency, be 16.7HZ, by current signal and the sampling of afterflow angle signal, coordinate to switch to when the control motor speed approaches rated speed that should frequency range next frequency range, be under the asymmetrical power supply running status at this frequency range motor, should shorten the running time of this frequency range as far as possible.The 6th stage, the DSC controller sends f/2 and triggers the driving signal, in per 4 half-waves of power supply, remove wherein 2 half-waves according to the optimum way that calculates, and to remaining 2 half-wave chopper controls, making the voltage fundamental frequency that is added on the motor is 1/2 of power frequency, be 25HZ, by current signal and the sampling of afterflow angle signal, coordinate to switch to when the control motor speed approaches rated speed that should frequency range next frequency range, be under the asymmetrical power supply running status at this frequency range motor, should shorten the running time of this frequency range as far as possible.The 7th stage, when motor speed reached 1/2 rated speed substantially, the DSC controller sent power frequency and triggers the driving signal, and namely all half-waves have trigger impulse, each power frequency half-wave of alternating current is carried out chopper control control, so just realized the transition process of motor from 25HZ to 50HZ.
The utility model has been realized level and smooth raising frequency soft start, has little starting current, high starting torque, and frequency-division section switches level and smooth characteristics, can make motor at heavy duty or fully loaded smooth starting down.Because discrete variable frequency soft start adopts the major loop structure of traditional thyristor soft start, only changed the control method that thyristor triggers, so cost does not increase, yet obviously is better than traditional thyristor soft start on performance, has realized being similar to the soft starting characteristic of frequency converter.Be mainly used in the occasion of the heavy duty of threephase asynchronous machine band or full load starting.
Realization of the present utility model is described for example, has described above-mentioned embodiment.But other variations of the present utility model and modification; be apparent for those skilled in the art, any modification/variation in essence disclosed in the utility model and basic principle scope or imitation conversion all belong to claim protection range of the present utility model.
Claims (6)
1. the discrete variable frequency soft start device of a Speedless sensor, comprise the threephase potential transformer that is connected between power supply and the motor, the three-phase anti-parallel thyristor, major loop and major loop control circuit that threephase current transformer constitutes, it is characterized in that described major loop adopts the major loop structure of traditional thyristor soft start; Described major loop control circuit comprises voltage synchronous signal acquisition circuit, voltage sampling circuit, high frequency constant current trigger element, current over-zero testing circuit, DSC controller, current sampling circuit; Wherein said voltage synchronous signal acquisition circuit, described voltage sampling circuit are connected between described main circuit power input and the described DSC controller, and described current sampling circuit, described current over-zero testing circuit are connected between described main circuit power output and the described DSC controller; Described high frequency constant current trigger element is connected between each thyristor control end of described major loop and the described DSC controller.
2. the discrete variable frequency soft start device of Speedless sensor according to claim 1 is characterized in that this device also comprises LCD, single-chip microcomputer and keyboard; Described threephase potential transformer respectively with three inputs of described three-phase anti-parallel thyristor, described voltage synchronous signal acquisition circuit, described voltage sampling circuit is connected, three outputs of described three-phase anti-parallel thyristor are connected with three inputs of described motor respectively by described threephase current transformer, the signal output part of described voltage synchronous signal acquisition circuit connects a voltage signal zero passage detection input of described DSC controller, another voltage signal that the signal output part of described voltage sampling circuit connects described DSC controller detects input, the signal output part of described current over-zero testing circuit connects a current signal zero passage detection input of described DSC controller, another current signal that the signal output part of described current sampling circuit connects described DSC controller detects input, the control signal output of described DSC controller connects the signal input part of described high frequency constant current trigger element, the signal output part of described high frequency constant current trigger element connects the control signal input of described three-phase anti-parallel thyristor, the data input/output terminal of described DSC controller connects the data I/O of described single-chip microcomputer, the demonstration signal output part of described single-chip microcomputer connects the signal input part of described LCD, and the signal output part of described keyboard connects the signal input part of described single-chip microcomputer.
3. according to the discrete variable frequency soft start device of claim 1 and 2 described Speedless sensors, it is characterized in that described current over-zero testing circuit is made of voltage transformer, diode bridge rectifier circuit and isolation optocoupler.
4. according to the discrete variable frequency soft start device of claim 1 and 2 described Speedless sensors, it is characterized in that the comparison circuit that amplifying circuit, comparator and the peripheral component that described voltage synchronous signal acquisition circuit is made up of voltage transformer, secondary amplifier chip and peripheral component formed, with door, Schmidt trigger constitutes.
5. according to the discrete variable frequency soft start device of claim 1 and 2 described Speedless sensors, it is characterized in that the amplifying circuit that described voltage sampling circuit is made up of voltage transformer, secondary amplifier chip and peripheral component constitutes.
6. according to the discrete variable frequency soft start device of claim 1 and 2 described Speedless sensors, it is characterized in that amplifying circuit, diode, electric capacity, resistance that described current sampling circuit is made up of current transformer, secondary amplifier chip and peripheral component constitute.
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| CN 201220717338 CN203057040U (en) | 2012-12-24 | 2012-12-24 | Discrete frequency-conversion soft starting device with no speed sensor |
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| CN 201220717338 CN203057040U (en) | 2012-12-24 | 2012-12-24 | Discrete frequency-conversion soft starting device with no speed sensor |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103618480A (en) * | 2013-11-07 | 2014-03-05 | 陕西科技大学 | Magnetic field vector control soft starter and control method thereof |
| CN103633910A (en) * | 2013-11-07 | 2014-03-12 | 陕西科技大学 | Voltage space vector control device and control method for soft start |
| CN103683276A (en) * | 2013-09-04 | 2014-03-26 | 华北水利水电大学 | An intelligent static state switch, a control system thereof, and a fault monitoring method |
| CN106026729A (en) * | 2016-08-07 | 2016-10-12 | 黎辉 | Alternating current motor isolation drive power supply device |
| CN106998167A (en) * | 2017-04-28 | 2017-08-01 | 麦克维尔空调制冷(武汉)有限公司 | A kind of realtime power factor angle detection method for solid-state soft initiator |
-
2012
- 2012-12-24 CN CN 201220717338 patent/CN203057040U/en not_active Expired - Fee Related
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103683276A (en) * | 2013-09-04 | 2014-03-26 | 华北水利水电大学 | An intelligent static state switch, a control system thereof, and a fault monitoring method |
| CN103683276B (en) * | 2013-09-04 | 2017-01-11 | 华北水利水电大学 | An intelligent static state switch, a control system thereof, and a fault monitoring method |
| CN103618480A (en) * | 2013-11-07 | 2014-03-05 | 陕西科技大学 | Magnetic field vector control soft starter and control method thereof |
| CN103633910A (en) * | 2013-11-07 | 2014-03-12 | 陕西科技大学 | Voltage space vector control device and control method for soft start |
| CN103633910B (en) * | 2013-11-07 | 2019-08-23 | 陕西科技大学 | A kind of space vector of voltage control device and its control method for soft start |
| CN106026729A (en) * | 2016-08-07 | 2016-10-12 | 黎辉 | Alternating current motor isolation drive power supply device |
| CN106998167A (en) * | 2017-04-28 | 2017-08-01 | 麦克维尔空调制冷(武汉)有限公司 | A kind of realtime power factor angle detection method for solid-state soft initiator |
| CN106998167B (en) * | 2017-04-28 | 2020-01-17 | 麦克维尔空调制冷(武汉)有限公司 | Real-time power factor angle detection method for solid-state soft starter |
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Granted publication date: 20130710 Termination date: 20181224 |