A control system and method for a z-source boost circuit

Abstract

The application provides a control system and method of a z-source boost circuit, when a load value is equal to a preset value, a voltage regulation module outputs a first standard current according to a standard voltage and a voltage of a first output source, and then a current regulation module outputs a modulation wave according to the first standard current and a current of the first output source, so that a first control unit can be controlled by double closed-loop control of voltage and current, stable voltage output is realized, and peripheral overcurrent protection and overvoltage protection circuits are removed. When the load value is not equal to the preset value, the current regulation module outputs a modulation wave according to a second standard current equal to a reference current and a current of the first output source, so that the first control unit can be controlled by single closed-loop control of current, stable current output is realized, and peripheral current protection can be removed. In this way, overvoltage protection of the z-source circuit can be effectively controlled, production cost is reduced, and the reliability of the system is improved.

Description

Technical Field

[0001] This application relates to the field of power electronics, and in particular to a control system and method for a z-source boost circuit. Background Technology

[0002] With the widespread application of renewable energy, power electronic converters have also developed rapidly, such as Z-source converters, which have boost-buck capabilities. They can control the DC bus voltage by adjusting the direct duty cycle and add direct vector to enable direct connection between the upper and lower bridge arms of the inverter, thereby improving system reliability. Therefore, they have great application prospects in distributed generation, wind power generation, fuel cell power supply and motor drive.

[0003] In a z-source converter, if the voltage boost is too high during the z-source circuit's boost process, the z-source converter may be damaged. Therefore, it is particularly important to control the overvoltage protection of the effective z-source circuit. Summary of the Invention

[0004] This application provides a control system and method for a z-source boost circuit, used to control the overvoltage protection of the z-source circuit.

[0005] In a first aspect, this application provides a control system for a z-source boost circuit, comprising:

[0006] The z-source circuit connects the first input source and the first output source and is used to boost the voltage of the first input source.

[0007] A sampling circuit, which is connected to the first input source and the first output source, is used to collect the voltage of the first input source, as well as the voltage and current of the first output source;

[0008] The controller includes a voltage regulation module, a current regulation module, and a control module. The voltage regulation module is connected to the sampling circuit and is used to output a first standard current based on a standard voltage and the voltage of the first output source when the load value equals a preset value. The current regulation module is connected to the voltage regulation module and the sampling circuit and is used to output a modulated wave based on the current of the first output source and the first standard current when the load value equals the preset value, and to output a modulated wave based on a second standard current equal to a reference current and the current of the first output source when the load value does not equal the preset value. The control module is connected to the current regulation module and is used to output a first control signal based on the modulated wave and a triangular carrier wave. The first control signal is used to control the on or off of the first control unit.

[0009] A first comparator, connected to the sampling circuit, is used to output a second control signal based on a first voltage divider value and a second voltage divider value. The second control signal is used to control the on or off of the second control unit. The first voltage divider value is obtained based on the voltage of the first input source, and the second voltage divider value is obtained based on the voltage of the first output source.

[0010] The first control unit and the second control unit are used together to control the z-source circuit to be in a through state or a non-through state.

[0011] Optionally, the controller further includes:

[0012] The second comparator is used to compare whether the load value is equal to the preset value. If yes, it outputs the standard voltage; if no, it assigns the reference current to the second standard current and outputs the second standard current.

[0013] A third comparator, connected to the voltage regulation module, is used to assign the maximum current to the first standard current when the first standard current is greater than the maximum current, and to assign the minimum current to the first standard current when the first standard current is less than the minimum current.

[0014] A fourth comparator, connected to the current regulation module, is used to assign the maximum modulation wave to the modulation wave output by the current regulation module when the modulation wave output by the current regulation module is greater than the maximum modulation wave, and to assign the minimum modulation wave to the modulation wave output by the current regulation module when the modulation wave output by the current regulation module is less than the minimum modulation wave.

[0015] Optionally, the sampling circuit collects the voltage and current of the first output source at preset time intervals.

[0016] Optionally, the z-source circuit includes:

[0017] The first inductor has its first terminal connected to the positive terminal of the first input source;

[0018] The positive terminal of the first diode is connected to the second terminal of the first inductor;

[0019] The second inductor has its first terminal connected to the negative terminal of the first diode;

[0020] The second diode has its anode connected to the second terminal of the second inductor and its cathode connected to the anode of the first output source.

[0021] The positive terminal of the first capacitor is connected to the negative terminal of the first diode and the first terminal of the second inductor, and the negative terminal of the second inductor is connected to the negative terminal of the first input source.

[0022] The negative terminal of the second capacitor is connected to the second terminal of the first inductor and the positive terminal of the first diode, and the positive terminal of the second capacitor is connected to the second terminal of the second inductor and the positive terminal of the second diode.

[0023] The positive terminal of the third capacitor is connected to the negative terminal of the second diode and the positive terminal of the first output source, and the negative terminal is connected to the negative terminal of the first capacitor and the negative terminal of the first output source.

[0024] Optionally, the sampling circuit includes: a first sampling circuit and a second sampling circuit;

[0025] The first sampling circuit includes:

[0026] The first resistor has its first end connected to the positive terminal of the first input source and the first end of the first inductor;

[0027] The second resistor has its first end connected to the second end of the first resistor, and its second end connected to the negative terminal of the first input source, the negative terminal of the first capacitor, the negative terminal of the third capacitor, and the negative terminal of the first output source.

[0028] The second sampling circuit includes:

[0029] The third resistor has its first end connected to the negative terminal of the second diode, the positive terminal of the third capacitor, and the positive terminal of the first output source;

[0030] The fourth resistor has its first end connected to the second end of the third resistor, and its second end connected to the negative terminal of the first input source, the negative terminal of the third capacitor, the negative terminal of the first capacitor, and the negative terminal of the first output source.

[0031] Optionally, the non-inverting input of the first comparator is connected to the second terminal of the first resistor and the first terminal of the second resistor, and the inverting input is connected to the second terminal of the third resistor and the first terminal of the fourth resistor.

[0032] Optionally, the first control unit includes a first control transistor, the drain of which is connected to the second terminal of the second inductor and the positive terminal of the second diode, and the gate of which is connected to the output terminal of the comparator.

[0033] Optionally, the second control unit includes a second control transistor, the drain of which is connected to the source of the first control transistor, the source of which is connected to the negative terminal of the first capacitor and the third capacitor, and the gate of which is connected to the controller.

[0034] Secondly, this application provides a control method for a z-source boost circuit, utilizing the control system of the z-source boost circuit in the first aspect and any possible design of the first aspect, the method comprising:

[0035] Collect the voltage and current of the first output source;

[0036] When the load value is equal to the preset value, a first standard current is output based on the standard voltage and the voltage of the first output source, and a modulated wave is output based on the first standard current and the current of the first output source; when the load value is not equal to the preset value, a modulated wave is output based on a second standard current equal to the reference current and the current of the first output source.

[0037] A first control signal is output based on the modulated wave and the triangular carrier wave. The first control signal is used to control the first control unit to be turned on or off.

[0038] The first control unit and the second control unit are used to control the z-source circuit to be in a through state or a non-through state. The conduction or shutdown of the second control unit is controlled by a second control signal. The second control signal is obtained based on a first voltage divider value and a second voltage divider value. The first voltage divider value is obtained based on the voltage of the first input source, and the second voltage divider value is obtained based on the voltage of the first output source.

[0039] Optionally, when the load value equals a preset value, a first standard current is output based on a standard voltage and the voltage of the first output source, and a modulated wave is output based on the first standard current and the current of the first output source; when the load value does not equal the preset value, a modulated wave is output based on a second standard current equal to the reference current and the current of the first output source, specifically including:

[0040] When the load value equals the preset value, a standard voltage is output. Based on the standard voltage and the voltage of the first output source, a first standard current is output. It is determined whether the first standard current is greater than the maximum current. If so, the maximum current is assigned to the first standard current. If not, it is determined whether the first standard current is less than the minimum current. If the first standard current is less than the minimum current, the minimum current is assigned to the first standard current. A modulated wave is output based on the first standard current and the voltage of the first output source.

[0041] When the load value is not equal to the preset value, the reference current is assigned to the second standard current, and the modulated wave is output according to the second standard current and the current of the first output source.

[0042] Determine whether the modulated wave is greater than the maximum modulated wave;

[0043] If yes, assign the maximum modulation wave value to the modulation wave; if no, compare whether the modulation wave is smaller than the minimum modulation wave. If the modulation wave is smaller than the minimum modulation wave, assign the minimum modulation wave value to the modulation wave.

[0044] The control system for the z-source boost circuit provided in this application includes a z-source circuit, a sampling circuit, a controller, a first comparator, a first control unit, and a second control unit. The controller includes a voltage regulation module, a current regulation module, and a control module. The z-source circuit is connected to a first input source and a first output source and is used to boost the voltage of the first input source. The sampling circuit is connected to the first input source and the first output source and is used to acquire the voltage of the first input source and the voltage and current of the first output source. The voltage regulation module is connected to the sampling circuit and is used to output a first standard circuit based on a standard voltage and the voltage of the first output source when the load value equals a preset value. The current regulation module is connected to the voltage regulation module and the sampling circuit and is used to output a modulated wave based on the current of the first output source and the first standard current when the load value equals a preset value. The current regulation module is also used to output a modulated wave based on a second standard current equal to a reference current and the current of the first output source when the load value does not equal a preset value. The control module is connected to the current regulation module and is used to output a first control signal based on the modulated wave and a triangular carrier wave. The first control signal is used to control the on or off of the first control unit. The first comparator is connected to the sampling circuit and outputs a second control signal based on the first and second voltage divider values. This second control signal controls the on / off state of the second control unit. The first voltage divider value is obtained from the voltage of the first input source, and the second voltage divider value is obtained from the voltage of the first output source. The first and second control units work together to control the z-source circuit to be in a shoot-through or non-shoot-through state. Therefore, when the load value equals a preset value, a first standard current is output based on the standard voltage and the voltage of the first output source. Then, a modulated wave is output based on the first standard current and the current of the first output source. This allows for stable voltage output through dual closed-loop control of voltage and current, thus eliminating the need for external overcurrent and overvoltage protection circuits. When the load value does not equal the preset value, a modulated wave is output based on a second standard current equal to the reference current and the current of the first output source. This allows for stable current output through single closed-loop control of current, thus eliminating the need for external current protection. This effectively controls the overvoltage protection of the z-source circuit while reducing production costs and improving system reliability. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figures 1-6 A structural diagram of a control system for a z-source boost circuit provided in an embodiment of this application;

[0047] Figures 7-8 This is a flowchart illustrating a control method for a z-source boost circuit according to an embodiment of this application. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0049] As described in the background section, if the voltage boost in the z-source circuit of a z-source converter is too high during the boost process, it may damage the z-source converter. Therefore, it is particularly important to control the overvoltage protection of the effective z-source circuit.

[0050] To address the aforementioned problems, this application proposes a control system for a z-source boost circuit, comprising a z-source circuit, a sampling circuit, a controller, a first comparator, a first control unit, and a second control unit. The controller includes a voltage regulation module, a current regulation module, and a control module. The z-source circuit is connected to a first input source and a first output source, and is used to boost the voltage of the first input source. The sampling circuit is connected to the first input source and the first output source, and is used to acquire the voltage of the first input source and the voltage and current of the first output source. The voltage regulation module is connected to the sampling circuit, and is used to output a first standard circuit based on a standard voltage and the voltage of the first output source when the load value equals a preset value. The current regulation module is connected to the voltage regulation module and the sampling circuit, and is used to output a modulated wave based on the current of the first output source and the first standard current when the load value equals a preset value. The current regulation module is also used to output a modulated wave based on a second standard current equal to a reference current and the current of the first output source when the load value does not equal a preset value. The control module is connected to the current regulation module, and is used to output a first control signal based on the modulated wave and a triangular carrier wave. The first control signal is used to control the on or off state of the first control unit. The first comparator, connected to the sampling circuit, outputs a second control signal based on the first and second voltage divider values. This second control signal controls the on / off state of the second control unit. The first voltage divider value is obtained from the voltage of the first input source, and the second voltage divider value is obtained from the voltage of the first output source. The first and second control units work together to control the z-source circuit to be in a shoot-through or non-shoot-through state. Therefore, when the load value equals the preset value, the voltage regulation module outputs a first standard current based on the standard voltage and the voltage of the first output source. Then, the current regulation module outputs a modulated wave based on the first standard current and the current of the first output source. This allows for stable voltage output through dual closed-loop control of voltage and current, eliminating the need for external overcurrent and overvoltage protection circuits. When the load value does not equal the preset value, the current regulation module directly outputs a modulated wave based on the second standard current equal to the reference current and the current of the first output source. This allows for stable current output through single closed-loop control of current, eliminating the need for external current protection. This effectively controls the overvoltage protection of the z-source circuit while reducing production costs and improving system reliability.

[0051] The technical solutions of this application will be described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0052] Figure 1 and Figure 2The diagram shows a circuit structure of a boost circuit according to an embodiment of this application. The boost circuit of this embodiment includes: a source circuit 101, sampling circuits 102 and 107, a controller 106, a first comparator 105, a first control unit 103 and a second control unit 104. The controller 106 includes a voltage regulation module 1062, a current regulation module 1064 and a control module 1065.

[0053] The z-source circuit 101 connects the first input source and the first output source, and is used to control the voltage U of the first input source. in1 The voltage is boosted. Sampling circuits 102 and 107, connected to the first input source and the first output source, are used to acquire the voltage U of the first input source. in1 and the voltage U of the first output source out1 The voltage regulation module 1062 is connected to the sampling circuit 107 and is used to adjust the voltage according to the standard voltage U when the load value Load_flag equals a preset value. * and the voltage U of the first output source out1 Output a first standard current I1*. The current regulation module 1064 is connected to the voltage regulation module 1062 and the sampling circuit 107, and is used to adjust the current I1* based on the first output source when the load value Load_flag equals a preset value. out And the first standard current I1* output modulation wave D, and when the load value Load_flag is not equal to the preset value, according to the reference current I ref Equal second standard current I2* and first output source current I out The output modulated wave D is used. Control module 1065 is connected to current regulation module 1064 and is used to output a first control signal g based on the modulated wave D and the triangular carrier wave. S1 First control signal g S1 This is used to control the on / off state of the first control unit 103. The first comparator 105 is connected to sampling circuits 102 and 107 and the second control unit 104, and is used to output a second control signal g based on the first and second voltage divider values. S2 The second control signal g S2 The first voltage divider value is based on the voltage U of the first input source, which controls the second control unit 104 to turn on or off. in1 The obtained second voltage divider value is based on the voltage U of the first output source. out1 The first control unit 103 and the second control unit 104 are used together to control the z-source circuit to be in a through-circuit state or a non-through-circuit state.

[0054] In some embodiments, the controller 106 further includes a second comparator 1061, a third comparator 1063, and a fourth comparator 1066. The second comparator 1061 compares whether the load value Load_flag is equal to a preset value. When the load value Load_flag is equal to the preset value, the second comparator 1061 outputs a standard voltage U. * When the load value Load_flag is not equal to the preset value, the second comparator 1061 will use the reference current I. ref Assigning the value to the second standard current I2* and outputting the second standard current I2*, the current value of the second standard current output by the second comparator 1061 is the current value of the reference current. Therefore, when the load value Load_flag equals the preset value, the second comparator 1061 outputs the standard voltage U. * When the load value Load_flag is not equal to the preset value, a second standard current is output. It should be noted that the reference current I... ref The load value Load_flag can be adjusted according to different loads, for example, the default value is 1.

[0055] The voltage regulation module 1062 is connected to the second comparator 1061 and the sampling circuit 107 to obtain the standard voltage U. * and the voltage U of the first output source out1 And according to the standard voltage U * and the voltage U of the first output source out1 Output the first standard current I1*.

[0056] Specifically, first calculate the standard voltage U. * and the voltage U of the first output source out1 Voltage difference ΔU=U * -U out1 Then, calculate I. v =I v +ΔU,I v This is the accumulation of voltage deviation values. It should be noted that this formula is essentially an integral formula, which is discretized after programming. Finally, based on ΔU and I... v Calculate the first standard current I1 * =P1ΔU+I1I v Where P1 and I1 are ΔU and I, respectively. v The coefficient can be set according to specific circumstances.

[0057] The third comparator 1063 is connected to the voltage regulation module 1062 and is used to ensure that the first standard current I1* output by the voltage regulation module 1062 is greater than the maximum current I. max At that time, the maximum current I maxThe value is assigned to the first standard current I1*, and the first standard current I1* output by the voltage regulation module 1062 is less than the minimum current I. min At that time, the minimum current I min The value is assigned to the first standard current I1*. Therefore, when the load value Load_flag equals the preset value, the current value of the first standard current I1* output by the third comparator 1063 is equal to the minimum current I. min The current value or maximum current I max The current value. Maximum current I max The current value and the minimum current I min The current value can be set according to the load requirements and the specifications of the control transistor. The current regulation module 1064 is connected to the second comparator 1061, the third comparator 1063, and the sampling circuit 107. When the load value Load_flag equals the preset value, the current regulation module 1064 adjusts the current according to the first standard current I1* output by the third comparator 1063 and the current I from the first output source sampled by the sampling circuit 107. out Output modulated wave D. When the load value Load_flag is not equal to the preset value, the current regulation module 1064 adjusts the current according to the second standard current I2* output by the second comparator 1061 and the current I from the first output source collected by the sampling circuit 107. out Output modulated wave D.

[0058] Specifically, first calculate the first standard current I1* or the second standard current I2* and the current I of the first output source. out Current difference ΔI=I1* / I2*-I out Then, calculate I. I =I I +ΔI,I I This is the accumulation of current deviation values. It should be noted that this formula is essentially an integral formula, which is discretized after programming. Finally, based on ΔI and I... I Calculate the modulated wave D = P2ΔI + I2I I Where P2 and I1 are ΔI and I, respectively. I The coefficient can be set according to specific circumstances.

[0059] The fourth comparator 1066 is connected to the current regulation module 1064 and is used when the modulation wave D output by the current regulation module 1064 is greater than the maximum modulation wave D. max At that time, the maximum modulation wave D max The modulated wave D output by the current regulation module 1064 is assigned a value, and the modulated wave D output by the current regulation module 1064 is less than the minimum modulated wave D. min At that time, the minimum modulation wave D min The value is assigned to the modulation wave D output by the current regulation module 1064. Maximum modulation wave Dmax and minimum modulation wave D min It can be set within the range of 0 to 1 according to specific requirements, for example, the maximum modulation wave D. max The minimum modulation wave D is 1. min It is 0.

[0060] The control module 1065 is connected to the fourth comparator 1066. The control module 1065 receives the modulation wave D, the value of which is equal to the value of the maximum modulation wave or the value of the minimum modulation wave. Based on the received modulation wave D and the triangular carrier wave, the control module 1065 outputs the first control signal g. S1 .

[0061] In some embodiments, the sampling circuit 107 acquires the voltage U of the first output source at preset time intervals. out1 and current I out This is to obtain relatively stable voltage and current. The preset time interval can be, for example, 50μs, and the current I of the first output source can be acquired using sampling methods such as low-resistance grounding or a current sensor. out .

[0062] Sampling circuits 102 and 107 acquire the voltage U of the first input source. in1 and the voltage U of the first output source out1 and current I out1 The first comparator 105 compares the input source U. in1 The first voltage division value obtained from the voltage and the voltage obtained from the first output source U out1 The second voltage division value is obtained from the voltage of the first comparator 105. When the first voltage division value is greater than the second voltage division value, the output terminal of the first comparator 105 outputs the first drive signal g. s1 First driving signal g s1 When the second control unit 104 is turned on, and the first voltage divider value is less than the second voltage divider value, the output terminal of the first comparator 105 outputs the second drive signal g. s2 The second driving signal g s2 The second control unit 104 is turned off.

[0063] The controller 106 uses pulse width modulation (PWM) to control the first control unit 103 to turn on or off. When the triangular carrier wave is less than the modulation wave D, the controller 106 controls the first control unit 103 to turn on. When the triangular carrier wave is greater than the modulation wave D, the controller 106 controls the first control unit 103 to turn off.

[0064] The first control unit 103 is connected to the z-source circuit 101, and the second control unit 104 is connected to the first control unit 103. The first control unit 103 and the second control unit 104 jointly control the z-source circuit 101 to be in a direct-through state or a non-direct-through state. When the first control unit 103 is on and the second control unit 104 is on, the z-source circuit 101 is in a direct-through state. When the first control unit 103 is off and the second control unit 104 is on, the z-source circuit 101 is in a non-direct-through state. When the first control unit 103 is on and the second control unit 104 is off, the z-source circuit 101 is in a non-direct-through state. When the first control unit 103 is off and the second control unit 104 is off, the z-source circuit 101 is in a non-direct-through state.

[0065] The first comparator 105 is connected to sampling circuits 102 and 107 and the second control unit 104, and obtains the voltage U of the first input source through sampling circuits 102 and 107. in1 and the voltage U of the first output source out1 Compare the voltage U from the first input source in1 The obtained first voltage divider value and the voltage U from the first output source out1 The second voltage divider value is obtained, and a second drive signal g is issued based on the comparison result. S2 When the comparison result indicates that the first voltage divider value is greater than the second voltage divider value, the second control unit 104 is turned on; when the comparison result indicates that the first voltage divider value is less than the second voltage divider value, the second control unit 104 is turned off.

[0066] In some embodiments, reference Figure 1 As shown, the z-source circuit includes a first inductor L1, a first diode D1, a second inductor L2, a second diode D2, a first capacitor C1, a second capacitor C2, and a third capacitor C3. The first terminal of the first inductor L1 is connected to the positive terminal of the first input source. The positive terminal of the first diode D1 is connected to the second terminal of the first inductor L1. The first terminal of the second inductor L2 is connected to the negative terminal of the first diode D1. The positive terminal of the second diode D2 is connected to the second terminal of the second inductor L2, and the negative terminal of the second diode D2 is connected to the negative terminal of the first output source. The positive terminal of the first capacitor C1 is connected to the negative terminal of the first diode D1 and the first terminal of the second inductor L2, and the negative terminal of the first capacitor C1 is connected to the first input source U. in1 The negative terminal of the first capacitor C2 is connected to the second terminal of the first inductor L1 and the positive terminal of the first diode D1. The positive terminal of the second capacitor C2 is connected to the second terminal of the second inductor L2 and the positive terminal of the second diode D2. The positive terminal of the third capacitor C3 is connected to the negative terminal of the second diode D2 and the positive terminal of the first output source. The negative terminal of the third capacitor C3 is connected to the negative terminal of the first capacitor C1 and the negative terminal of the first output source.

[0067] In some embodiments, sampling circuits 102 and 107 include a first sampling circuit 102 and a second sampling circuit 107. The first sampling circuit 102 includes a first resistor R1 and a second resistor R2. The first end of the first resistor R1 is connected to the positive terminal of the first input source and the first end of the first inductor L1. The first end of the second resistor R2 is connected to the second end of the first resistor R1. The second end of the second resistor R2 is connected to the negative terminal of the first input source and the negative terminal of the first output terminal. The second sampling circuit 107 includes a third resistor R3 and a fourth resistor R4. The first end of the third resistor R3 is connected to the negative terminal of the second diode D2, the third capacitor C3, and the positive terminal of the first output terminal. The first end of the fourth resistor R4 is connected to the second end of the third resistor R3. The second end of the fourth resistor R4 is connected to the negative terminal of the first output source, the negative terminal of the third capacitor C3, the negative terminal of the first capacitor C1, and the negative terminal of the first input source.

[0068] The first voltage divider value can be the voltage divided by the first input source occupied by the first resistor R1, and the second voltage divider value can be the voltage divided by the first output source occupied by the fourth resistor R4. Therefore, when the first voltage divider value is greater than the second voltage divider value, i.e., U... in1 R2 / (R1+R2)>U out1 When R4 / (R3+R4), the first comparator 105 controls the second control unit 104 to conduct. When the triangular carrier wave is less than the modulated wave D, the controller 106 controls the first control unit 103 to conduct. When both the first control unit 103 and the second control unit 104 are conducting, the z-source circuit 101 is in a direct-on state. At this time, the operating mode of the z-source circuit 101 is as follows: Figure 3 As shown, the first diode D1 and the second diode D2 are turned off, the first inductor L1, the second inductor L2 and the second capacitor C2 store energy, and the first capacitor C1 and the third capacitor C3 release energy.

[0069] The circuit equation for the direct-through state is:

[0070]

[0071] When the first voltage divider value is greater than the second voltage divider value, i.e., U in1 R2 / (R1+R2)>U out1 When R4 / (R3+R4), the first comparator 105 controls the second control unit 104 to turn on. When the triangular carrier wave is greater than the modulation wave D, the controller 106 controls the first control unit 103 to turn off. When the first control unit 103 is on and the second control unit 104 is off, the z-source circuit 101 is in a non-straight-through state. At this time, the working mode of the z-source circuit 101 is as follows: Figure 4 As shown, the first inductor L1, the second inductor L2, and the second capacitor C2 release energy, while the first capacitor C1 and the third capacitor C3 store energy.

[0072] The circuit equation for the non-straight-through state is:

[0073]

[0074] Since the Z sources are symmetrically distributed, U C2 =U C1 According to the volt-second theorem, the integral of the voltage across the inductor is 0 within one switching cycle T. Assuming the shoot-through duty cycle is D, then according to formulas (1) and (2), we can obtain:

[0075]

[0076] That is: D0(U C3 +U C1 )=D0(3U C1 -U in1 )=D0(3U C2 -U in1 )=(D0-1)(U in1 -U C2 (4)

[0077] (1-4D0)U C2 =(1-2D0)(U in1 (5)

[0078] Simplifying formulas (4) and (5), we get:

[0079] U C1 =U C2 = (1-2D) / (1-4D)U in1 (6)

[0080] U C3 =1 / (1-4D)U in1 (7)

[0081] Then, according to formulas (1), (2), and (7), we can know that:

[0082] U out1 =U C3 =1 / (1-4D)U in1 (8)

[0083] Thus, U in1 R2 / (R1+R2)>U out1When R4 / (R3+R4), the first comparator 105 controls the second control unit 104 to conduct. When the triangular carrier wave is less than the modulation wave D, the controller 106 controls the first control unit 103 to conduct. The first control unit 103 and the second control unit 104 control the Z-source circuit 101 to be in a shoot-through state. Subsequently, when the triangular carrier wave is greater than the modulation wave D, the controller 106 controls the first control unit 103 to be turned off. The first control unit 103 and the second control unit 104 control the Z-source circuit 101 to be in a non-shoot-through state, thereby enabling the Z-source circuit to operate in boost mode.

[0084] When the first voltage divider value is less than the second voltage divider value, i.e., U in1 R2 / (R1+R2)<U out1 When R4 / (R3+R4), the first comparator 105 controls the second control unit 104 to turn off. When the triangular carrier wave is less than the modulated wave D, the controller 106 controls the first control unit 103 to turn on. With the first control unit 103 on and the second control unit 104 off, the z-source circuit 101 is in a non-straight-through state. At this time, the operating mode of the z-source circuit 101 is as follows: Figure 5 As shown, the first inductor L1, the second inductor L2, and the second capacitor C2 release energy, while the first capacitor C1 and the third capacitor C3 store energy. The voltage U of the first input source... in1 Equal to the voltage U of the first output source out1 When the first voltage divider value is greater than the second voltage divider value, i.e., U in1 R2 / (R1+R2)<U out1 When R4 / (R3+R4), the first comparator 105 controls the second control unit 104 to turn off. When the triangular carrier wave is greater than the modulated wave D, the controller 106 controls the first control unit 103 to turn off. With both the first control unit 103 and the second control unit 104 off, the Z-source circuit 101 is in a non-straight-through state. At this time, the operating mode of the Z-source circuit 101 is as follows: Figure 6 As shown, the first inductor L1, the second inductor L2, and the second capacitor C2 release energy, while the first capacitor C1 and the third capacitor C3 store energy. The first input source U... in1 The voltage is equal to that of the first output source U. out1 The voltage.

[0085] Thus, U in1 R2 / (R1+R2)<U out1When R4 / (R3+R4), the first comparator 105 controls the second control unit 104 to turn off. When the triangular carrier wave is less than the modulation wave D, the controller 106 controls the first control unit 103 to turn on. The first control unit 103 and the second control unit 104 control the Z-source circuit 101 to be in a non-straight-through state. Then, when the triangular carrier wave is greater than the modulation wave D, the controller 106 controls the first control unit 103 to turn off, and the first control unit 103 and the second control unit 104 control the Z-source circuit 101 to be in a non-straight-through state. Then U in1 R2 / (R1+R2)<U out1 When R4 / (R3+R4) is equal to 1, the second control unit 104 is turned off, causing the voltage U of the first output source to be reduced. out1 The voltage drops, thus completing the overvoltage protection.

[0086] The non-inverting input of the first comparator 105 is connected to the second terminal of the first resistor R1 and the first terminal of the second resistor R2, and the inverting input is connected to the second terminal of the third resistor R3 and the first terminal of the fourth resistor R4. Therefore, the first comparator 105 can compare the voltage of the second resistor R2 with the voltage of the fourth resistor R4, that is, compare U. in1 R2 / (R1+R2) and U out1 R4 / (R3+R4). When the second resistor R2 is greater than the fourth resistor R4, i.e., U... in1 R2 / (R1+R2)>U out1 When R4 / (R3+R4), the first comparator 105 controls the second control unit 104 to turn on. When the second resistor R2 is less than the fourth resistor R4, i.e., U... in1 R2 / (R1+R2) out1 When R4 / (R3+R4) is equal to the voltage, the first comparator 105 controls the second control unit 104 to shut down. This achieves hardware voltage protection through resistors and the first comparator, saving on component costs and resources.

[0087] In some embodiments, the first control unit 103 includes a first control transistor S1, the drain of which is connected to the second terminal of the second inductor L2 and the anode of the second diode D2, and the gate of which is connected to the output of the first comparator 105. The first control transistor S1 is turned on or off under the control of the first comparator 105. The second control unit 104 includes a second control transistor S2, the drain of which is connected to the source of the first control transistor S1, and the source of which is connected to the cathode of the first capacitor C1 and the third capacitor C3. The gate of the second control transistor S2 is connected to a controller 106, and the second control transistor S2 is turned on or off under the control of the controller 106.

[0088] ​The control system of the z-source boost circuit provided in this application has been described in detail above. An embodiment of this application also provides a control method for the z-source boost circuit. (Refer to...) Figure 7 As shown, Figure 7 The flowchart shown is a control method for a z-source boost circuit according to an embodiment of this application. With a controller as the executing entity, the method of this embodiment may include the following steps:

[0089] S10, Collect the voltage U of the first output source. out1 and current I out .

[0090] S20. When the load value Load_flag equals the preset value, according to the standard voltage U... * and the voltage U of the first output source out1 Output first standard current I1 * And according to the first standard current I1 * and the current I of the first output source out The output modulated wave D, when the load value Load_flag is not equal to the preset value, is based on the reference current I. ref Equal second control current I2 * and the current I of the first output source out Output modulated wave D.

[0091] S30. Output the first control signal g based on the modulation wave D and the triangular carrier wave. S1 First control signal g S1 Used to control the on or off of the first control unit.

[0092] The first control unit and the second control unit are used to control the z-source circuit to be in a through state or a non-through state. The conduction or shutdown of the second control unit is controlled by a second control signal, which is obtained based on a first voltage divider value and a second voltage divider value. The first voltage divider value is obtained based on the voltage of the first input source, and the second voltage divider value is obtained based on the voltage of the first output source.

[0093] In some embodiments, reference Figure 8 As shown, the process includes: S101, acquiring the voltage and current of the first output source. S102, determining whether the load value is equal to a preset value. If yes, proceed to step S103; otherwise, proceed to step S104. S103, based on the voltage U of the first output source... out1 and standard voltage U * Output first standard current I1 * Then, proceed to step S105. S104: Assign the reference current to the second standard current I2. * and outputs the second standard current I2 *Then, proceed to step S106. S105: Determine the first standard current I1. * Is it greater than the maximum current I? max If yes, proceed to step S107; otherwise, proceed to step S109. S106: According to the second standard current I2... * and the current I of the first output source out Output the modulated wave D. Then, execute step S108. S107, convert the maximum current I... max Assigned to the first standard current I1 * Then, proceed to step S106. S108: Determine whether the modulated wave D is greater than the maximum modulated wave D. max If yes, proceed to step S110; otherwise, proceed to step S112. S109: Determine the first standard current I1. * Is it less than the minimum current I? min If yes, proceed to step S111; otherwise, proceed to step S106. S110: Modulate the maximum modulation wave D... max Assign the value to the modulation wave D. Then, end the process. S111, set the minimum current I... min Assigned to the first standard current I1 * Then, proceed to step S106. S112: Determine whether the modulating wave D is less than the minimum modulating wave D. min If yes, proceed to step S114; otherwise, end the process. S114: Modulate the minimum modulation wave D... min Assign the value to the modulated wave D.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A control system for a z-source boost circuit, characterized in that, include: The z-source circuit connects the first input source and the first output source and is used to boost the voltage of the first input source. A sampling circuit, which is connected to the first input source and the first output source, is used to collect the voltage of the first input source, as well as the voltage and current of the first output source; The controller includes a voltage regulation module, a current regulation module, and a control module. The voltage regulation module is connected to the sampling circuit and is used to output a first standard current based on the standard voltage and the voltage of the first output source when the load value is equal to a preset value. The current regulation module is connected to the voltage regulation module and the sampling circuit, and is used to output a modulated wave according to the current of the first output source and the first standard current when the load value is equal to the preset value, and to output a modulated wave according to the second standard current equal to the reference current and the current of the first output source when the load value is not equal to the preset value; the control module is connected to the current regulation module, and is used to output a first control signal according to the modulated wave and the triangular carrier wave, the first control signal being used to control the first control unit to be turned on or off; A first comparator, connected to the sampling circuit, is used to output a second control signal based on a first voltage divider value and a second voltage divider value. The second control signal is used to control the on or off of the second control unit. The first voltage divider value is obtained based on the voltage of the first input source, and the second voltage divider value is obtained based on the voltage of the first output source. The first control unit and the second control unit are used together to control the z-source circuit to be in a through state or a non-through state; The controller also includes: The second comparator is used to compare whether the load value is equal to the preset value. If yes, it outputs the standard voltage; if no, it assigns the reference current to the second standard current and outputs the second standard current. A third comparator, connected to the voltage regulation module, is used to assign the maximum current to the first standard current when the first standard current output by the voltage regulation module is greater than the maximum current, and to assign the minimum current to the first standard current when the first standard current output by the voltage regulation module is less than the minimum current; when the load value is equal to a preset value, the current regulation module outputs a modulation wave D based on the first standard current output by the third comparator and the current of the first output source acquired by the sampling circuit; when the load value is not equal to the preset value, the current regulation module outputs a modulation wave D based on the second standard current output by the second comparator and the current of the first output source acquired by the sampling circuit. A fourth comparator, connected to the current regulation module, is used to assign the maximum modulation wave value to the modulation wave output by the current regulation module when the modulation wave output by the current regulation module is greater than the maximum modulation wave value, and to assign the minimum modulation wave value to the modulation wave output by the current regulation module when the modulation wave output by the current regulation module is less than the minimum modulation wave value. The control module is connected to the fourth comparator. The control module receives a modulation wave value equal to the maximum modulation wave value or the minimum modulation wave value, and outputs a first control signal based on the received modulation wave and the triangular carrier wave.

2. The control system according to claim 1, characterized in that, The sampling circuit collects the voltage and current of the first output source at preset time intervals.

3. The control system according to claim 1 or 2, characterized in that, The z-source circuit includes: The first inductor has its first terminal connected to the positive terminal of the first input source; The positive terminal of the first diode is connected to the second terminal of the first inductor; The second inductor has its first terminal connected to the negative terminal of the first diode; The second diode has its anode connected to the second terminal of the second inductor and its cathode connected to the anode of the first output source. The positive terminal of the first capacitor is connected to the negative terminal of the first diode and the first terminal of the second inductor, and the negative terminal of the second inductor is connected to the negative terminal of the first input source. The negative terminal of the second capacitor is connected to the second terminal of the first inductor and the positive terminal of the first diode, and the positive terminal of the second capacitor is connected to the second terminal of the second inductor and the positive terminal of the second diode. The positive terminal of the third capacitor is connected to the negative terminal of the second diode and the positive terminal of the first output source, and the negative terminal is connected to the negative terminal of the first capacitor and the negative terminal of the first output source.

4. The control system according to claim 3, characterized in that, The sampling circuit includes: a first sampling circuit and a second sampling circuit; The first sampling circuit includes: The first resistor has its first end connected to the positive terminal of the first input source and the first end of the first inductor; The second resistor has its first end connected to the second end of the first resistor, and its second end connected to the negative terminal of the first input source, the negative terminal of the first capacitor, the negative terminal of the third capacitor, and the negative terminal of the first output source. The second sampling circuit includes: The third resistor has its first end connected to the negative terminal of the second diode, the positive terminal of the third capacitor, and the positive terminal of the first output source; The fourth resistor has its first end connected to the second end of the third resistor, and its second end connected to the negative terminal of the first input source, the negative terminal of the third capacitor, the negative terminal of the first capacitor, and the negative terminal of the first output source.

5. The control system according to claim 4, characterized in that, The non-inverting input of the first comparator is connected to the second terminal of the first resistor and the first terminal of the second resistor, and the inverting input is connected to the second terminal of the third resistor and the first terminal of the fourth resistor.

6. The control system according to claim 5, characterized in that, The first control unit includes a first control transistor, the drain of which is connected to the second terminal of the second inductor and the positive terminal of the second diode, and the gate of which is connected to the output terminal of the first comparator.

7. The control system according to claim 6, characterized in that, The second control unit includes a second control transistor, the drain of which is connected to the source of the first control transistor, the source of which is connected to the negative terminals of the first capacitor and the third capacitor, and the gate of which is connected to the controller.

8. A control method for a z-source boost circuit, characterized in that, The control system utilizing the z-source boost circuit according to any one of claims 1-7, the method comprising: Collect the voltage and current of the first output source; When the load value is equal to the preset value, a first standard current is output based on the standard voltage and the voltage of the first output source, and a modulated wave is output based on the first standard current and the current of the first output source; when the load value is not equal to the preset value, a modulated wave is output based on a second standard current equal to the reference current and the current of the first output source. A first control signal is output based on the modulated wave and the triangular carrier wave. The first control signal is used to control the first control unit to be turned on or off. Wherein, the wave value of the modulated wave is equal to the wave value of the maximum modulated wave or the wave value of the minimum modulated wave. The first control unit and the second control unit are used to control the z-source circuit to be in a direct-on state or a non-direct-on state. The conduction or shutdown of the second control unit is controlled by a second control signal. The second control signal is obtained based on a first voltage divider value and a second voltage divider value. The first voltage divider value is obtained based on the voltage of the first input source, and the second voltage divider value is obtained based on the voltage of the first output source. When the load value equals a preset value, a first standard current is output based on the standard voltage and the voltage of the first output source, and a modulated wave is output based on the first standard current and the current of the first output source; when the load value does not equal the preset value, a modulated wave is output based on a second standard current equal to the reference current and the current of the first output source, specifically including: When the load value equals the preset value, a standard voltage is output. Based on the standard voltage and the voltage of the first output source, a first standard current is output. It is determined whether the first standard current is greater than the maximum current. If so, the maximum current is assigned to the first standard current. If not, it is determined whether the first standard current is less than the minimum current. When the first standard current is less than the minimum current, the minimum current is assigned to the first standard current. A modulated wave is output based on the first standard current and the current of the first output source. When the load value is not equal to the preset value, the reference current is assigned to the second standard current, and the modulated wave is output according to the second standard current and the current of the first output source. Determine whether the modulated wave is greater than the maximum modulated wave; If yes, assign the maximum modulation wave value to the modulation wave; if no, compare whether the modulation wave is smaller than the minimum modulation wave. If the modulation wave is smaller than the minimum modulation wave, assign the minimum modulation wave value to the modulation wave.

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