CN107885128A - The high-power resistive load of continuously adjustabe based on alternating expression PWM - Google Patents
The high-power resistive load of continuously adjustabe based on alternating expression PWM Download PDFInfo
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- CN107885128A CN107885128A CN201711257101.7A CN201711257101A CN107885128A CN 107885128 A CN107885128 A CN 107885128A CN 201711257101 A CN201711257101 A CN 201711257101A CN 107885128 A CN107885128 A CN 107885128A
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- load
- pwm
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- 238000006243 chemical reaction Methods 0.000 claims abstract description 6
- 238000001514 detection method Methods 0.000 claims description 8
- 238000001914 filtration Methods 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 7
- 230000005611 electricity Effects 0.000 claims description 4
- 238000002955 isolation Methods 0.000 claims description 4
- 239000003990 capacitor Substances 0.000 claims description 2
- 238000004891 communication Methods 0.000 claims description 2
- 238000000034 method Methods 0.000 claims 1
- 238000010276 construction Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000003321 amplification Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
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- 230000007274 generation of a signal involved in cell-cell signaling Effects 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
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Classifications
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/04—Programme control other than numerical control, i.e. in sequence controllers or logic controllers
- G05B19/042—Programme control other than numerical control, i.e. in sequence controllers or logic controllers using digital processors
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/04—Programme control other than numerical control, i.e. in sequence controllers or logic controllers
- G05B19/042—Programme control other than numerical control, i.e. in sequence controllers or logic controllers using digital processors
- G05B19/0423—Input/output
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- G05F5/00—Systems for regulating electric variables by detecting deviations in the electric input to the system and thereby controlling a device within the system to obtain a regulated output
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K7/00—Modulating pulses with a continuously-variable modulating signal
- H03K7/08—Duration or width modulation ; Duty cycle modulation
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B2219/00—Program-control systems
- G05B2219/20—Pc systems
- G05B2219/21—Pc I-O input output
- G05B2219/21137—Analog to digital conversion, ADC, DAC
Abstract
The invention discloses a kind of high-power resistive load of alternating expression continuously adjustabe based on PWM, the system mainly includes power lines, control circuit and control algolithm three parts, it is characterised in that：The power lines include filter circuit and PWM switching power circuits；The control circuit includes DSP or MCU circuits, power tube driver circuit, measure voltage ＆ current circuit and auxiliary power supply circuit；Control algolithm resistance as requested or power conversion go out the time of switching tube conducting, so as to control the resistance of line attachment to change input voltage or electric current, reach to loading resistance continuously adjustable purpose.The advantage of the invention is that:It is controllable to realize load, the program control adjustment of load discontinuity of tradition is efficiently solved, the problems such as load can not make full use of, available for large-power occasions.
Description
Technical field
The present invention relates to a kind of adjustable electronic load device of high power CW, more particularly to it is a kind of based on pulsewidth modulation
Alternating expression continuously adjustabe high power load circuit and its control algolithm.
Background technology
Controllable test load is broadly divided into program-controlled electric resistive load and electronic load, and program control load mainly passes through switching device
Control resistance is switched in or out, so as to realize the controllability of resistance.Program control load can be divided into resistance according to access way difference
Parallel and resistor string, the program control load of resistor string are led to as shown in figure 1, microcontroller sends signal as needed
Overdrive the turn-on and turn-off of circuit controlling switch device, resistance line attachment when switching off, and resistance when the switch is closed
It is short-circuited, is not accessed equivalent to resistance.The program control load of resistor coupled in parallel formula is as shown in Fig. 2 its operation principle formula in series with a resistor
Similar, resistance accesses when switch closes.Subject matter existing for this controllable load：
1）Resistance is unable to continuously adjustabe, and resistance interval depends on the resistance of single resistance；
2）Bearing power can not make full use of, when some of which resistance is removed, load it is total bear power significantly under
Drop.
Electronic load line construction is as shown in figure 3, using transistor linearity area, by controlling the electric current of base stage to realize to collection
The control of electrode and emitter current, or MOSFET linear zones are utilized, realized by the voltage of control gate to drain electrode and source
The control of electrode current, so as to realize to the adjustable simulation of load resistance.Electronic load has continuous adjustability, but its disadvantage
To be difficult to use in relatively high power, its power is consumed by power device completely, and device has higher temperature, therefore for requirement on devices
It is higher.
The content of the invention
The technical problems to be solved by the invention are so that load has the advantages of above-mentioned load, while avoid the two from being had
The shortcomings that having, it is proposed that a kind of alternating expression continuously adjustabe high power load circuit based on PWM, it is program control negative to efficiently solve tradition
The problems such as adjustment discontinuity load can not make full use of is carried, also solves the problems such as power limit of electronic load, the present invention
Designed load can be used for large-power occasions, while there is a wide range of continuously adjustabe of load resistance, bearing power to make full use of
The advantages that.
To achieve these goals, the present invention adopts the following technical scheme that：
Alternating expression continuously adjustabe high power load based on PWM, as shown in Fig. 2 system is made up of power lines and control circuit,
Power lines include filter circuit and PWM switching power circuits；Control circuit includes core cpu circuit, detection circuit, driving
Circuit and auxiliary power supply circuit.
The PWM switching powers circuit has each load branch to be formed in parallel, and each load branch is then by load resistance with opening
Pipe is closed to connect to be formed.
The filter circuit is then made up of electric capacity and inductance, is responsible for filtering the fluctuation of switching mode load branch, if power supply source
Then filtered for voltage source using LC, current source is then filtered using electric capacity.
The core cpu circuit is made up of MCU or FPGA, A/D chip etc., is responsible for the execution of algorithm.
The detection line route composition such as transformer and amplifier, is responsible for the detection of input voltage and electric current.
The power tube driver circuit is made up of optocoupler and driving element, is responsible for isolation and the power drive of signal.
The auxiliary power supply circuit is then responsible for the power supplies such as MCU, driver circuit, detection circuit.
The control algolithm, obtains maximum value when being supported on all switch off, resistance is infinity；In all switches
The minimum value of load resistance is obtained when closing completely, resistance is the parallel value of all load resistances；With switching tube drive signal
The dutycycle of conducting changes from 100%-0, and load resistance can be achieved from minimum value to maximum consecutive variations.Electricity as requested
Resistance or power conversion go out the time that resistance branch switching tube needs to turn in a cycle, when adjusting each branch switch conducting
Between, the control to input current is realized, is equivalent to the continuous adjustment to load resistance.The switch of switching tube is adopted between each load branch
With phase cross-over mode, so as to reduce the ripple of load current, the requirement of system input filter circuit is reduced.
Specific workflow：Detect input voltage first and input current, input voltage divided by input current obtain in real time
Line equivalent resistance, equivalent resistance obtains its deviation compared with requiring resistance, by compensating fortune to deviation
The adjustment amount of pulsewidth needed for obtaining is calculated, this adjustment amount adjusts the ON time of power tube after driver circuit, further adjusts
Whole input current or input voltage, so as to the deviation for reducing line equivalent resistance He requiring resistance.In a word, when require resistance become
It is to adjust input current when inputting as constant pressure source by adjusting pulsewidth input current or voltage change during change, and inputs
To adjust input voltage during constant-current source so that line equivalent resistance tracking fixed valure changes, and realizes the mesh of adjustment load resistance
's.
The beneficial effects of the invention are as follows：
The present invention uses the alternating expression continuously adjustabe high power load based on PWM, compared with adjustable load, has following excellent
Gesture：
（1）Load equivalent resistance continuously adjustabe, can more preferably meet needs.
（2）With larger bearing power, much larger than the power characteristic of electronic load.
（3）Circuit substantially reduces the pressure-resistant and temperature requirement to load switch pipe, because electronic load power tube is main
Heater members, and the line power pipe is only responsible for the on and off of load resistance, non-principal heater members.
（4）Circuit has less ripple, due to staggeredly being turned on using multichannel loading, substantially reduces the line of input current
Ripple.
Brief description of the drawings：
The program control load of Fig. 1 resistor strings；
The program control load of Fig. 2 resistor coupled in parallel formulas；
Fig. 3 electronic load line assumption diagrams；
Fig. 4 is the alternating expression continuously adjustabe high power load based on PWM of the present invention.
Embodiment
The present invention will be further described with example below in conjunction with the accompanying drawings：
The program control load of Fig. 1 resistor strings, power lines are formed by multiple resistant series, and each resistance is in parallel with switching device even
Connect, switching device is relay or device for power switching, according to control circuit logical drive switch device conductive or closure, when opening
Resistance is bypassed when closing device closure, and resistance no current flows through.The resistance of varying number is accessed according to power lines, so as to adjust
Overall load resistance size.
The program control load of Fig. 2 resistor coupled in parallel formulas, power lines are formed by a plurality of branch circuit parallel connection, resistance and switch in every branch road
Devices in series connects, and switching device is relay or device for power switching, according to control circuit logical drive switch device conductive
Or closure, the resistance access power circuit when switching device closes, according to the resistance of power lines access varying number, so as to adjust
Whole overall load resistance size.
Fig. 3 electronic load line assumption diagrams, loop of power circuit are a transistor or multiple coupled in parallel, utilize crystal
The Linear Control characteristic of pipe, the power current between collector and emitter is controlled by the base current of controlling transistor, from
And the ratio for voltage and current is realized, equivalent resistance is adjusted as needed.
Fig. 4 is the alternating expression continuously adjustabe high power load based on PWM of the present invention；The system has power lines, control
Circuit and control algolithm three parts composition.Power lines are mainly made up of filter circuit and PWM switching power circuit two parts；
Control circuit is then made up of detection circuit, auxiliary power supply circuit, core cpu circuit and driver circuit；Control algolithm is then comprising number
According to compositions such as collection, the calculating of required load and drive signal generations.
Filter circuit, filters out the ripple brought due to the switching characteristic of controllable load, line construction according to input source not
It is same and different.When input source is voltage source, filter circuit can use LC filtering or direct capacitance filtering；But input source is electricity
During stream source, filter circuit then uses capacitor filtering.
PWM switching power circuits, are loaded with a plurality of branch circuit parallel connection composition, in every branch road resistance with after diodes in parallel
Connected again with switching tube, resistance selectes resistance as needed and power, switching tube are responsible for switching on and off for resistance, and diode is born
Blame the afterflow of the stray inductances of such as wire resistor itself.
Detect the detection of circuit, predominantly input voltage and electric current, the isolation comprising signal.Circuit by voltage transformer,
Current transformer and the difference amplifier composition for signal condition, high voltage, high current input, which are converted to, to be suitable for
CPU low-voltage signal.
Auxiliary power supply circuit, it is responsible for detecting the suitable power of offer such as circuit, driver circuit, core cpu circuit.Generally
It is the voltages such as required direct current 5V, 3.3V the alternating current 220V voltage conversion of power frequency using flyback line topological.
Driver circuit, be responsible for CPU output low-power level signals to be converted to signal needed for power switch pipe, it is specific include every
From with power amplification two parts.
Core cpu circuit, the hardware for being responsible for algorithm performs, and using MCU, DSP or FPGA as core, additional power supply, port turn
Thread-changing road, communication line etc. form.
Control algolithm, obtains maximum value when being supported on all switch off, resistance is infinity；And all switches are completely
The minimum value of load resistance is obtained during closure, resistance is the parallel value of all load resistances；As switching tube drive signal turns on
Dutycycle from 100%-0 change, load resistance from minimum value to maximum consecutive variations.
Resistance value or power conversion as requested goes out the time that resistance branch switching tube needs to turn in a cycle,
Each branch switch ON time is adjusted, realizes the control to input current, is equivalent to the continuous adjustment to load resistance.Each load
The switch of switching tube uses phase cross-over mode between branch road, so as to reduce the ripple of load current, reduces system input filtering
The requirement of circuit.
Specific workflow：Detect input voltage first and input current, input voltage divided by input current obtain in real time
Line equivalent resistance, equivalent resistance obtains its deviation compared with requiring resistance, by compensating fortune to deviation
The adjustment amount of pulsewidth needed for obtaining is calculated, this adjustment amount adjusts the ON time of power tube after driver circuit, further adjusts
Whole input current or input voltage, so as to the deviation for reducing line equivalent resistance He requiring resistance.In a word, when require resistance become
It is to adjust input current when inputting as constant pressure source by adjusting pulsewidth input current or voltage change during change, and inputs
To adjust input voltage during constant-current source so that line equivalent resistance tracking fixed valure changes, and realizes the mesh of adjustment load resistance
's.
Claims (8)
1. the alternating expression continuously adjustabe high power load based on PWM, including power lines, control circuit and control algolithm, it is special
Sign is：Described power lines are connected by load resistance with switching tube to be formed, in parallel between each load branch；Described control is returned
Road includes DSP or MCU circuits, power tube driver circuit, measure voltage ＆ current circuit and auxiliary power supply circuit；Described control is calculated
Method resistance value as requested or power conversion go out the time that resistance branch switching tube needs to turn in a cycle, and regulation is each
Branch switch ON time, the control to input current is realized, be equivalent to the continuous adjustment to load resistance；Described each load
The switch of switching tube uses phase cross-over mode between branch road, so as to reduce the ripple of load current, reduces system input filtering
The requirement of circuit.
2. the alternating expression continuously adjustabe high power load according to claim 1 based on PWM, it is characterised in that：Described
Filter circuit structure is according to the different and different of input source, and when input source is voltage source, filter circuit can use LC to filter
Or direct capacitance filtering；When input source is current source, filter circuit then uses capacitor filtering.
3. the alternating expression continuously adjustabe high power load according to claim 1 based on PWM, it is characterised in that：Described
Power lines, a plurality of branch circuit parallel connection composition is loaded with, resistance is connected with switching tube again with after diodes in parallel in every branch road, electricity
Selected resistance and power, switching tube are responsible for switching on and off for resistance as needed for resistance, and diode is responsible for wire resistor etc. itself
Stray inductance afterflow.
4. the alternating expression continuously adjustabe high power load according to claim 1 based on PWM, it is characterised in that：Described
Detection circuit is mainly the detection of input voltage and electric current, and the isolation comprising signal, circuit is by voltage transformer, current transformer
With the difference amplifier composition for signal condition, high voltage, high current signal input, which are converted to, is suitable for the low of CPU
Press signal.
5. the alternating expression continuously adjustabe high power load according to claim 1 based on PWM, it is characterised in that：Described
Auxiliary power supply circuit is responsible for detecting the suitable power of offer such as circuit, driver circuit, core cpu circuit, generally use flyback
Line topological, it is the voltages such as required direct current 5V, 3.3V the alternating current 220V voltage conversion of power frequency.
6. the alternating expression continuously adjustabe high power load according to claim 1 based on PWM, it is characterised in that：Described
Driver circuit is responsible for CPU output low-power level signals to be converted to signal needed for power switch pipe, specific to include isolation and power
Amplify two parts.
7. the alternating expression continuously adjustabe high power load according to claim 1 based on PWM, it is characterised in that：Described
Core cpu circuit be responsible for algorithm hardware perform, using MCU, DSP or FPGA as core, by additional power supply, port translation circuit,
Communication line etc. forms.
8. the alternating expression continuously adjustabe high power load according to claim 1 based on PWM, it is characterised in that：Described
Control algolithm is supported on all maximums that load resistance is obtained when switching off, and all switches obtain load electricity when closing completely
The minimum value of resistance, resistance are the parallel value of all load resistances, as the dutycycle of switching tube drive signal conducting is from 100%-0
Change, resistance can be achieved from minimum value to maximum consecutive variations.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711257101.7A CN107885128A (en) | 2017-12-04 | 2017-12-04 | The high-power resistive load of continuously adjustabe based on alternating expression PWM |
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|---|---|---|---|
| CN201711257101.7A CN107885128A (en) | 2017-12-04 | 2017-12-04 | The high-power resistive load of continuously adjustabe based on alternating expression PWM |
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| CN107885128A true CN107885128A (en) | 2018-04-06 |
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| CN201711257101.7A Pending CN107885128A (en) | 2017-12-04 | 2017-12-04 | The high-power resistive load of continuously adjustabe based on alternating expression PWM |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109870661A (en) * | 2019-02-25 | 2019-06-11 | 湖南福德电气有限公司 | High power continuous variable tunable load and its application method, computer readable storage medium |
| CN110581641A (en) * | 2019-09-16 | 2019-12-17 | 华中科技大学 | Device and method for reducing power consumption of linear adjusting tube of parallel linear filter |
| CN112051838A (en) * | 2020-09-16 | 2020-12-08 | 奇瑞汽车股份有限公司 | Test system and method of EPS controller |
| CN114221315A (en) * | 2021-12-14 | 2022-03-22 | 广东福德电子有限公司 | Efficient direct-current resistance-inductance load quick disconnection method |
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| CN114221315A (en) * | 2021-12-14 | 2022-03-22 | 广东福德电子有限公司 | Efficient direct-current resistance-inductance load quick disconnection method |
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Application publication date: 20180406 |