CN112953210B - Converter-based double-zero-clearing single-cycle system and control method - Google Patents

Abstract

The invention provides a converter-based double-clearing single-cycle system and a control method. The system includes a power circuit and a control circuit. The power circuit is composed of an input DC power supply, an input filter inductor, a switch tube, a diode, an output filter capacitor and a control circuit. The control circuit is composed of a current sensor, an amplifier, an integrating circuit, a comparator, an RS flip-flop, an OR gate comparator, and a reset switch; first, the current reference value is set, and the current of the converter switch tube is sampled by the current sensor, and then passes through After amplification and integration, it is compared with the reference current, the comparison result is input to the R terminal of the RS flip-flop, the Q terminal of the output result is connected to the base of the switch, and the Q terminal and the clock signal of the RS flip-flop are jointly input to the OR gate comparator, or gate comparison The output of the device is connected to the base of the reset switch; the double-clearing single-cycle control method provided by the present invention is subject to the dual control of the integral value comparison signal and the clock frequency, which can realize the zero-clearing at a constant frequency, shorten the convergence time, and can make the transformation system to obtain optimal dynamic performance.

Description

A converter-based dual-clearing single-cycle system and control method

technical field

The present invention relates to the technical field of converter control, in particular to a converter-based double-clearing single-cycle system and a control method.

Background technique

A DC converter is a power electronic device that converts DC power into voltage or current controllable DC power required by a load. It chops the constant DC voltage into a series of pulse voltages by fast on and off control of power electronic devices, and changes the pulse width of the pulse series by controlling the change of the duty cycle, so as to realize the adjustment of the average value of the output voltage. After filtering by the output filter, the DC power with controllable current or voltage is obtained on the controlled load.

The closed-loop control of the DC converter generally uses a PI controller. PI control can achieve no static error of the control target, but the dynamic performance of the control target cannot be optimized.

In 1995, American scholars proposed a nonlinear control strategy-One Cycle Control (OCC). The single-cycle control controls the switching duty cycle, so that the average value of the switching variable in each switching cycle is exactly equal to or proportional to the control reference value, so the converter system under single-cycle control has fast dynamic response, constant switching frequency and robustness. Strong and easy to implement. Compared with the traditional linear feedback control, the application of single-cycle control saves the regulator of the converter system and avoids the correction time of the regulator error, so it has a faster response speed. At the same time, the single-cycle control can realize the suppression of the input quantity pulsation in one switching cycle, which improves the dynamic response speed of the system.

However, the reset signal of single-cycle control can only be generated when the integral value of the switching variable reaches the control reference value. Therefore, if the integral value cannot reach the control reference value within one switching cycle, the integral value cannot be cleared normally, and the system adjustment cycle will be is elongated and the dynamic response of the system slows down.

SUMMARY OF THE INVENTION

Purpose of the invention: In view of the problem of slow system dynamic response in the above-mentioned background technology, the present invention provides a double-clearing single-cycle system and a control method for a converter, which are used to solve the problem of load abrupt change in the existing single-cycle control technology. The integral value cannot be cleared normally, which affects the dynamic performance of the control target.

Technical scheme: In order to realize the above-mentioned purpose, the technical scheme adopted in the present invention is:

A converter-based double-clearing single-cycle system, characterized in that it includes a power circuit and a control circuit;

The power circuit includes a DC power supply, a filter inductor, a switch tube, a diode, a filter capacitor and a load; the DC power supply is connected in series with the filter inductor and then connected to the switch tube collector and the diode anode, respectively; the switch tube emitter and the other end of the DC power supply After being connected, it is connected to the strong electric ground; the cathode of the diode is connected to a section of the filter capacitor, and the other end of the filter capacitor is connected to the emitter of the switching tube; the load is connected in parallel to both ends of the filter capacitor;

连接至或门比较器的一端，与另一端同时输入的触发信号进行比较后，输出清零信号；所述清零信号输入至复位开关。The control circuit includes a current sensor, an amplifier, an integrator, a comparator, an RS flip-flop, an OR gate comparator and a reset switch; the current sensor is arranged between the emitter of the switch tube and the strong electric ground, and the current signal obtained by sampling connected to the negative input terminal of the amplifier; the positive input terminal of the amplifier is connected to the weak ground; a first input resistor is connected between the negative input terminal and the output terminal of the amplifier; the output terminal of the amplifier is connected to the negative input terminal of the integrator terminal, the positive input terminal of the integrator is connected to the weak ground; a capacitor C is connected between the negative input terminal and the output terminal of the integrator; the two ends of the capacitor C are connected in parallel with a reset switch, and the emitter of the reset switch is connected to The negative input terminal of the integrator, the collector is connected to the output terminal of the integrator through the second input resistor; the output terminal of the integrator is connected to the positive input terminal of the comparator, and is compared with the current reference value i _ref input to the negative input terminal Then output to the R terminal of the RS flip-flop; the S terminal of the RS flip-flop inputs a trigger signal; the output terminal Q of the RS flip-flop is connected to the base of the switch tube; the output terminal

It is connected to one end of the OR gate comparator, and after being compared with the trigger signal simultaneously input at the other end, a clearing signal is output; the clearing signal is input to the reset switch.

A control method for adopting the above-mentioned converter-based double-clearing single-cycle system, comprising the following steps:

Step S1.1, setting the current reference value i _ref and the trigger signal;

Step S1.2, sampling the switching tube current of the boost converter through the current sensor, and obtaining the switching tube current amplification value after passing through the amplifier; passing the obtained switching tube current amplification value through the integrating circuit to obtain the integral value of the switching tube current; Input the integral value of the switch tube current to the positive terminal of the comparator, and input the current reference value i _ref to the negative terminal of the comparator for comparison;

Step S1.3, connect the output end of the comparator to the R input end of the RS trigger, and connect the trigger signal to the S input end of the RS trigger; when the integral value of the switch current is less than i _ref , the comparator The output terminal is 0, the R input signal of the RS flip-flop is 0, Q=1, the switch tube is turned on, the switch tube current continues to increase, and the integral value of the switch tube current increases; when the integral value of the switch tube current is greater than i _ref , the output of the comparator is 1, Q=0, the switch is turned off;

输出端输入到或门比较器的另一端，所述开关管电流的积分值清零信号确定方法如下：Step S1.4, input the trigger signal to one end of the OR gate comparator, and connect the RS trigger

The output end is input to the other end of the OR gate comparator, and the method for determining the reset signal of the integral value of the switch current is as follows:

Step S1.4.1. Between the two high levels of the trigger signal, when the integral value of the switch tube current is greater than i _ref , at this moment, the integral value of the switch tube current reset signal is 1, and the integral value is 1. If the circuit is cleared, then when the second high level of the trigger signal is ready for the clearing operation, the integrating circuit has been cleared;

Step S1.4.2. Between the two high levels of the trigger signal, when the integral value of the switch tube current is always less than i _ref , then at the second high level moment of the trigger signal, the integral value of the switch tube current is cleared. The zero signal is 1, and the integrating circuit is cleared.

Beneficial effects:

In the converter double-clearing single-cycle system and control method proposed by the present invention, in the dynamic process of the change of the converter load, the integral value clearing mode of the single-cycle controller is double-controlled by the integral value comparison signal and the clock frequency, and can The realization of constant frequency clearing shortens the convergence time, so that the convergence time of any load sudden change is not affected by abnormal clearing, so that the DC converter system has the best dynamic performance.

Description of drawings

Fig. 1 is the double clearing single-cycle system structure diagram based on converter provided by the present invention;

Fig. 2 is the working waveform diagram of traditional single-cycle control method in the prior art;

FIG. 3 is a working waveform diagram of the converter-based dual clearing single-cycle system control method provided by the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

As shown in Figure 1, a converter-based double-clearing single-cycle system includes a power circuit and a control circuit;

The power circuit includes a DC power supply, a filter inductor, a switch tube, a diode, a filter capacitor and a load; the DC power supply is connected in series with the filter inductor and then connected to the switch tube collector and the diode anode respectively; the switch tube emitter is connected to the other end of the DC power supply and then connected to a strong Electric ground; the cathode of the diode is connected to a section of the filter capacitor, and the other end of the filter capacitor is connected to the emitter of the switching tube; the load is connected in parallel with both ends of the filter capacitor.

连接至或门比较器的一端，与另一端同时输入的触发信号进行比较后，输出清零信号；所述清零信号输入至复位开关。The control circuit includes a current sensor, an amplifier, an integrator, a comparator, an RS flip-flop, an OR gate comparator, and a reset switch. The current sensor is arranged between the emitter of the switch tube and the strong electric ground, and the sampled current signal is connected to the negative input terminal of the amplifier through the resistor R1; the positive input terminal of the amplifier is connected to the weak electric ground through the resistor R2; the negative input of the amplifier A first feedback resistor R3 is connected between the terminal and the output terminal; the output terminal of the amplifier is connected to the negative input terminal of the integrator through the resistor R4, and the positive input terminal of the integrator is connected to the weak ground through the resistor R5; A capacitor C is connected between the negative input terminal and the output terminal; a reset switch is connected in parallel with both ends of the capacitor C, the reset switch emitter is connected to the negative input terminal of the integrator, and the collector is connected to the integrator through the second feedback resistor R6. The output end of the integrator is connected to the output end of the integrator; the output end of the integrator is connected to the positive input end of the comparator through the resistor R7, and is output to the R end of the RS flip-flop after being compared with the current reference value i _ref input from the negative input end; the RS The trigger signal is input to the S terminal of the flip-flop; the output terminal Q of the RS flip-flop is connected to the base of the switch; the output terminal

It is connected to one end of the OR gate comparator, and after being compared with the trigger signal simultaneously input at the other end, a clearing signal is output; the clearing signal is input to the reset switch.

The converter system provided by the present invention adopts a double-clearing single-cycle control method, and the steps are as follows:

Step S1.1, setting the current reference value i _ref and the trigger signal;

Step S1.2, sampling the switching tube current of the boost converter through the current sensor, and obtaining the switching tube current amplification value after passing through the amplifier; passing the obtained switching tube current amplification value through the integrating circuit to obtain the integral value of the switching tube current; Input the integral value of the switch tube current to the positive terminal of the comparator, and input the current reference value i _ref to the negative terminal of the comparator for comparison;

Step S1.3, connect the output end of the comparator to the R input end of the RS trigger, and connect the trigger signal to the S input end of the RS trigger; when the integral value of the switch current is less than i _ref , the comparator The output terminal is 0, the R input signal of the RS flip-flop is 0, Q=1, the switch tube is turned on, the switch tube current continues to increase, and the integral value of the switch tube current increases; when the integral value of the switch tube current is greater than i _ref , the output of the comparator is 1, Q=0, the switch is turned off;

输出端输入到或门比较器的另一端，所述开关管电流的积分值清零信号确定方法如下：Step S1.4, input the trigger signal to one end of the OR gate comparator, and connect the RS trigger

The output end is input to the other end of the OR gate comparator, and the method for determining the reset signal of the integral value of the switch current is as follows:

Step S1.4.1. Between the two high levels of the trigger signal, when the integral value of the switch tube current is greater than i _ref , at this moment, the integral value of the switch tube current reset signal is 1, and the integral value is 1. If the circuit is cleared, then when the second high level of the trigger signal is ready for the clearing operation, the integrating circuit has been cleared;

Step S1.4.2. Between the two high levels of the trigger signal, when the integral value of the switch tube current is always less than i _ref , then at the second high level moment of the trigger signal, the integral value of the switch tube current is cleared. The zero signal is 1, and the integrating circuit is cleared.

The following is an analysis and comparison of the prior art in Figs. 2-3 and the technical solution of the present patent to further illustrate the technical effect of the present invention.

时刻，开关管电流的积分值为3T_c，开关管关断。即在第三个时钟周期中，开关管的占空比已经退饱和，即占空比小于1。而在

时刻，实际上第三个时钟周期内开关管电流的安秒积仅为T_c。所以传统单周期控制方法不能及时使得积分值清零(清零时刻如图2中箭头所示)，积分值的叠加使得开关管占空比减小，影响了电流上升率，影响了动态性能。直到第13个时钟周期，电流才能达到给定值。Figure 2 shows the working waveform diagram of the traditional single-cycle control method. The control reference value of the switch current is 3T _c , where T _c is the clock cycle. At the end of the first clock cycle, the integral value of the switch tube current is 0.5T _c , because 0.5T _c <3T _c , the switch tube is always on in the first clock cycle; the current integral value is 0.5T _c and is not cleared , 0.5T _c will be added to the integral value of the second clock cycle. At the end of the second clock cycle, the integral value of the switch tube current is 2T _c . Since 2T _c <3T _c , the switch tube current in the second clock cycle is 2T c . It is always on; for the same reason, since the integral value 2T _c is not cleared, 2T _c will be superimposed on the integral value of the third clock cycle.

At the moment, the integral value of the switch tube current is 3T _c , and the switch tube is turned off. That is, in the third clock cycle, the duty cycle of the switch has been desaturated, that is, the duty cycle is less than 1. while in

At the moment, in fact, the ampere-second product of the switch tube current in the third clock cycle is only T _c . Therefore, the traditional single-cycle control method cannot clear the integral value in time (the time of clearing is shown by the arrow in Figure 2). The current cannot reach the given value until the 13th clock cycle.

时刻，第四个时钟周期的积分值为3T_c，开关管关断。仅到第10个时钟周期，电流就能达到给定值。As shown in FIG. 3 , the control reference value of the switch tube current is 3T _c , and T _c is the clock cycle. At the end of the first clock cycle, the integral value of the switch tube current is 0.5T _c . Since 0.5T _c <3T _c , the switch tube is always on in the first clock cycle; since the integral value of 0.5T _c is cleared, 0.5T _c will not be added to the integrated value of the first clock cycle. At the end of the second clock cycle, the integrated value of the switch tube current is 1.5T _c . Since 1.5T _c <3T _c , the switch tube current in the second clock cycle is 1.5T c . It is always on; in the same way, since the integral value 1.5T _c is cleared to zero, 1.5T _c will not be added to the integral value of the third clock cycle. At the end of the third clock cycle, the integral value of the switch current is 2.5T _c , since 2.5T _c < 3T _c , the switch tube is always on in the third clock cycle; since the integral value 2.5T _c is cleared, in

At the moment, the integral value of the fourth clock cycle is 3T _c , and the switch is turned off. Only by the 10th clock cycle, the current can reach the given value.

To sum up, the double-clearing single-cycle system and the control method provided by the present invention can ensure that the integral values do not overlap, and indirectly increase the duty cycle, thereby improving the dynamic performance of the current. Double-clearing single-cycle control method of the converter In the dynamic process of the converter load changing, the integral value clearing mode of the single-cycle controller is double controlled by the integral value comparison signal and the clock frequency, which can realize the clearing at a constant frequency , shortening the convergence time, so that the convergence time of any load sudden change is not affected by abnormal clearing, so that the DC converter system has the best dynamic performance.

It should be noted that, in addition to the Boost converter system provided in this embodiment, the double-clearing single-cycle control method provided by the present invention can also be applied to other DC-DC converter systems, as well as DC-AC converter systems, AC-DC converters system and AC-AC converter system, it should be considered that the technical solutions related to the above converter system should be included in the protection scope of the present invention. For those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can also be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims (1)

1. A control method of a converter-based dual-clearing single-cycle system, the double-clearing single-cycle system comprising a power circuit and a control circuit; The power circuit includes a DC power supply, a filter inductor, a switch tube, a diode, a filter capacitor and a load; the DC power supply is connected in series with the filter inductor and then connected to the switch tube collector and the diode anode, respectively; the switch tube emitter and the other end of the DC power supply After being connected, it is connected to the strong electric ground; the cathode of the diode is connected to one end of the filter capacitor, and the other end of the filter capacitor is connected to the emitter of the switching tube; the load is connected in parallel to both ends of the filter capacitor; The control circuit includes a current sensor, an amplifier, an integrator, a comparator, an RS flip-flop, an OR gate and a reset switch; the current sensor is arranged between the emitter of the switch tube and the strong electric ground, and the sampled current signal is connected to the The negative input terminal of the amplifier; the positive input terminal of the amplifier is connected to the weak ground; the first input resistance is connected between the negative input terminal and the output terminal of the amplifier; the output terminal of the amplifier is connected to the negative input terminal of the integrator, The positive input terminal of the integrator is connected to the weak ground; a capacitor C is connected between the negative input terminal and the output terminal of the integrator; the two ends of the capacitor C are connected in parallel with a reset switch, and the emitter of the reset switch is connected to the integrator Negative input terminal, the collector is connected to the output terminal of the integrator through the second input resistor; the output terminal of the integrator is connected to the positive input terminal of the comparator, and is output after comparing with the current reference value i _ref input from the negative input terminal to the R terminal of the RS flip-flop; the S terminal of the RS flip-flop inputs a trigger signal; the output terminal Q of the RS flip-flop is connected to the base of the switch tube; the output terminal

It is connected to one end of the OR gate, and after performing the OR operation with the trigger signal input at the other end at the same time, the reset signal is output; the reset signal is input to the G pole of the reset switch; It is characterized in that, the control method comprises the following steps: Step S1.1, setting the current reference value i _ref and the trigger signal; Step S1.2, sampling the switching tube current of the boost converter through the current sensor, and obtaining the switching tube current amplification value after passing through the amplifier; passing the obtained switching tube current amplification value through the integrating circuit to obtain the integral value of the switching tube current; Input the integral value of the switch tube current to the positive terminal of the comparator, and input the current reference value i _ref to the negative terminal of the comparator for comparison; Step S1.3, connect the output end of the comparator to the R input end of the RS trigger, and connect the trigger signal to the S input end of the RS trigger; when the integral value of the switch current is less than i _ref , the comparator The output terminal is 0, the R input signal of the RS flip-flop is 0, Q=1, the switch tube is turned on, the switch tube current continues to increase, and the integral value of the switch tube current increases; when the integral value of the switch tube current is greater than i _ref , the output of the comparator is 1, Q=0, the switch is turned off; Step S1.4, input the trigger signal to one end of the OR gate, and connect the RS trigger

The output end is input to the other end of the OR gate, and the method for determining the reset signal of the integral value of the switch current is as follows: Step S1.4.1. Between the two high levels of the trigger signal, when the integral value of the switch tube current is greater than i _ref , at this moment, the integral value of the switch tube current reset signal is 1, and the integral value is 1. If the circuit is cleared, then when the second high level of the trigger signal is ready for the clearing operation, the integrating circuit has been cleared; Step S1.4.2. Between the two high levels of the trigger signal, when the integral value of the switch tube current is always less than i _ref , then at the second high level moment of the trigger signal, the integral value of the switch tube current is cleared. The zero signal is 1, and the integrating circuit is cleared.

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