CN103729008A

CN103729008A - Wide-current-range alternating-current and constant-current source compensation type control strategy

Info

Publication number: CN103729008A
Application number: CN201210385567.6A
Authority: CN
Inventors: 丁印福; 周凤兰
Original assignee: SHENYANG JUNYIN TECHNOLOGY Co Ltd
Current assignee: SHENYANG JUNYIN TECHNOLOGY Co Ltd
Priority date: 2012-10-12
Filing date: 2012-10-12
Publication date: 2014-04-16
Anticipated expiration: 2032-10-12
Also published as: CN103729008B

Abstract

Provided is a wide-current-range alternating-current and constant-current source compensation type control strategy. According to a constant-current source, one of a plurality of current sensors at the secondary side of a transformer is selected as outer ring current input, one of a plurality of current sensors at the primary side of the transformer is selected as inner ring current input, output signals calculated by a first PID are used as input, and after calculation of a compensation circuit, the output signals are used as input signals for calculation of a second PID. After compensation of a control circuit, the direct current component in calculation of the first PID can be completely eliminated, the saturation problem of the transformer is solved, system dynamic response is improved, and the strategy is suitable for extra-wide load resistance values.

Description

Wide-range current AC constant-current source offset-type control strategy

Technical field

The present invention relates to a kind of wide-range current AC constant-current source control strategy, can adapt to extremely wide Standard resistance range load, especially can eliminate DC error component, promote the dynamic response performance of constant current source.

Background technology

At present, ac current source industry is generally used the SPWM inverter structure of Power Electronic Technique, and wherein control strategy adopts single electric current loop PID control strategy more, or double-current ring PID control strategy.For single electric current loop PID control strategy, exist dynamic response slow, transformer is saturated shortcoming easily; For double-current ring PID control strategy, first order PID easily produces DC error component, causes transformer saturated, and the response performance of constant current source cannot further promote, and adapts to loading range narrower.

In order to overcome the low-response of existing AC constant-current source, transformer is easily saturated, there is DC component in output, adapt to the narrower shortcoming of loading range, the invention provides a kind of wide-range current constant current source offset-type control strategy, this control strategy not only can make the alternating current precision of power supply output high, dynamic response is fast, and can eliminate the DC component in PID control, eliminating transformer saturation problem, makes constant current source can adapt to the load of extremely wide Standard resistance range.

The technical solution adopted for the present invention to solve the technical problems is: transformer secondary limit and a limit adopt respectively one or more current sensors to gather transformer secondary limit electric current and limit electric current of transformer, and gauge tap device is limit electric current of transformer of gating and a transformer secondary limit electric current metering-in control system respectively.By transformer secondary limit electric current and the given input end that accesses respectively No. 1 PID of current reference, by the input end of the output signal of No. 1 PID 1 access penalty function.When the satisfied gain of control system requires, the output signal 2 of penalty function is directly received the input end of No. 2 PID, when the satisfied gain of control system requires, the output signal of penalty function 2 is received after proportion operational amplifier computing to the input end of No. 2 PID, limit electric current of transformer is also accessed to the input end of No. 2 PID simultaneously.Output signal 3 access SPWM circuit for generating, SPWM circuit for generating output single-pole or the bipolar SPWM signals of No. 2 PID.

This control strategy benefit is: when first order PID output exists DC error component, penalty function can be eliminated DC error component wherein, thereby eliminates the DC component in final SPWM drive waveforms frequency spectrum, eliminating transformer saturation problem.Penalty function has been adjusted the transport function of constant current source simultaneously, has promoted the response speed of system, dynamic property, the ability of adaptation wide region load.

Accompanying drawing explanation

Below in conjunction with drawings and Examples, the present invention is further described.

Fig. 1 is control principle drawing of the present invention.

Fig. 2 is the equivalent simulation circuit diagram of first embodiment of offset-type control strategy.

Fig. 3 is the digital algorithm process flow diagram of first embodiment of offset-type control strategy.

Fig. 4 is the Bode diagram of Fig. 2 circuit under specific resistance and capacitance.

Fig. 5 is the step response of Fig. 2 transport function under specific resistance and capacitance.

Embodiment

In Fig. 1, transformer secondary limit and a limit adopt respectively one or more current sensors to gather transformer secondary limit electric current and limit electric current of transformer, and gauge tap device is limit electric current of transformer of gating and a transformer secondary limit electric current metering-in control system respectively.By transformer secondary limit electric current and the given input end that accesses respectively No. 1 PID of current reference, by the input end of the output signal of No. 1 PID 1 access penalty function.When the satisfied gain of control system requires, the output signal 2 of penalty function is directly received the input end of No. 2 PID, when the satisfied gain of control system requires, the output signal of penalty function 2 is received after proportion operational amplifier computing to the input end of No. 2 PID, limit electric current of transformer is also accessed to the input end of No. 2 PID simultaneously.Output signal 3 access SPWM circuit for generating, SPWM circuit for generating output single-pole or the bipolar SPWM signals of No. 2 PID.

In embodiment illustrated in fig. 2, the equivalent simulation circuit expressions of penalty function mainly consists of operational amplifier U1 and compensating resistance electric capacity.By resistance R 1 and capacitor C 1 series connection, the inverting input of access operational amplifier U1, No. 1 PID output signal 1 of another termination; The input end in the same way of resistance R 2 access operational amplifier U1, other end ground connection; By resistance R 3 and capacitor C 2 parallel connections, be serially connected between the inverting input and output terminal of operational amplifier U1; The output terminal of operational amplifier is the output signal 2 of control circuit by way of compensation.

In the penalty function Digital Implementation scheme shown in Fig. 3, the sampling period of whole penalty function is T, e (k) is the currency of No. 1 PID output signal 1, e (k-1) is a front sampled value of No. 1 PID output signal 1, and K is compensating parameter (R1, R3, C1 and C2 determine jointly in Fig. 2).Each sampling period, while arriving, is passed to e (k-1) by currency e (k), and the output signal of No. 1 PID 1 is passed to e (k), and e (k) is multiplied by the K output signal 2 of function by way of compensation with the difference of e (k-1).

In Fig. 4, the Bode diagram of penalty function can be changed by the impact of selected resistance capacitance parameter, parabola shaped but basic waveform all presents.In first embodiment of the present invention, data point 1 has embodied the attenuation of penalty function to DC component, the attenuation of first embodiment large with-50dB.Data point 2 is shearing frequency points, data point 3 is maximum gain points, data point 4 is second zero crossing, the gain waveform integral body of penalty function presents parabola shaped, there are two zero crossings (data point 2 and data point 4), a maximum of points (data point 3), peak value place waveform is greater than 0, and all the other waveforms are less than 0.

In Fig. 5, the step response of penalty function is subject to the impact of selected resistance capacitance parameter that this can occur to change, but basic waveform all presents after an overshoot, the characteristic making zero gradually.Under the step response that in first embodiment of the present invention, the step response of penalty function is 1 at input range, system reaches 10.7 times of maximum gains at 3.31ms.When step response is input as-1, whole waveform is along time T ime rotational symmetry.

Claims

1. a wide-range current AC constant-current source offset-type control strategy, its circuit feature is: transformer secondary limit and a limit adopt respectively one or more current sensors to gather transformer secondary limit electric current and limit electric current of transformer, and gauge tap device is limit electric current of transformer of gating and a transformer secondary limit electric current metering-in control system respectively.By transformer secondary limit electric current with current reference is given accesses respectively the input end that No. 1 PID circuit removes, by the input end of the output signal of No. 1 PID 1 access penalty function.When the satisfied gain of control system requires, the output signal 2 of penalty function is directly received the input end of No. 2 PID, when the satisfied gain of control system requires, the output signal of penalty function 2 is received after proportion operational amplifier computing to the input end of No. 2 PID, limit electric current of transformer is also accessed to the input end of No. 2 PID simultaneously.The final output signal 3 by No. 2 PID produces unipolarity or ambipolar SPWM signal.Output signal 3 access SPWM circuit for generating, SPWM circuit for generating output single-pole or the bipolar SPWM signals of No. 2 PID.

2. wide-range current AC constant-current source offset-type control strategy as claimed in claim 1, its equivalent simulation circuit feature is: by resistance R 1 and capacitor C 1 series connection, the inverting input of access operational amplifier U1, No. 1 PID output signal 1 of another termination; The input end in the same way of resistance R 2 access operational amplifier U1, other end ground connection; By resistance R 3 and capacitor C 2 parallel connections, be serially connected between the inverting input and output terminal of operational amplifier U1; The output terminal of operational amplifier is the output signal 2 of control circuit by way of compensation.

3. wide-range current AC constant-current source offset-type control strategy as claimed in claim 1, its digital control program feature is: the sampling period of penalty function is T, e (k) is the currency of No. 1 PID output signal 1, e (k-1) is a front sampled value of No. 1 PID output signal 1, and K is compensating parameter (R1, R3, C1 and C2 determine jointly in Fig. 2).Each sampling period, while arriving, is passed to e (k-1) by currency e (k), and the output signal of No. 1 PID 1 is passed to e (k), and e (k) is multiplied by the K output signal 2 of function by way of compensation with the difference of e (k-1).

4. wide-range current AC constant-current source offset-type control strategy as claimed in claim 1, its Bode diagram feature is: the gain waveform integral body of penalty function presents parabola shaped, there are two zero crossings (data point 2 and data point 4), a maximum of points (data point 3), peak value place waveform is greater than 0, and all the other waveforms are less than 0.

5. wide-range current AC constant-current source offset-type control strategy as claimed in claim 1, its step feature is: under the step response that penalty function is 1 at input range, present after an overshoot, make zero gradually.When step response is input as-1, whole waveform is along time T ime rotational symmetry.

6. switching device as claimed in claim 1 is used the mechanical switchs such as relay-contactor, or uses optical relay, or the switch that is combined into of other electronic components.