A dual-flow simplex composite energy storage system for a micro linear energy conversion system

Abstract

This invention discloses a dual-current simplex composite energy storage system for a micro linear energy conversion system, comprising: an H-bridge PWM drive module, a dual-current simplex DC-DC power conversion module, and a supercapacitor-battery composite energy storage module; the supercapacitor-battery composite energy storage module, the load, and the relay K are connected in series to form a loop; the H-bridge PWM drive module and the dual-current simplex DC-DC power conversion module are connected in parallel with the supercapacitor-battery composite energy storage module, and a first filter capacitor C1 is connected in parallel between the H-bridge PWM drive module and the dual-current simplex DC-DC power conversion module, and a second filter capacitor C2 is connected in parallel between the dual-current simplex DC-DC power conversion module and the supercapacitor-battery composite energy storage module.

Description

Technical Field

[0001] This invention relates to the field of energy and power technology, specifically to a dual-flow simplex composite energy storage system for a micro linear energy conversion system. Background Technology

[0002] In a micro linear power conversion system (MFP), the linear motor functions as both a motor providing compression kinetic energy to the piston and a generator outputting fuel and releasing chemical energy during a single work cycle. Its maximum power point occurs during power generation, where the electrical energy output as a generator exceeds the energy consumed in motor mode, creating an energy surplus. This surplus needs to be stored and utilized by an energy storage device. Furthermore, the switching between motor and generator modes causes transient power fluctuations, making it difficult to maintain stable power output and significantly impacting power quality on the DC bus. Equipping the system with a storage device of a certain capacity can help maintain a dynamic balance between motoring and generation, suppress power fluctuations, and stabilize voltage.

[0003] Therefore, the energy storage device of a micro linear energy conversion system not only needs to have a certain energy storage capacity to absorb the energy continuously released by the system, but also needs to meet the requirements of instantaneous high-power charging / discharging and high-frequency input / output switching. Furthermore, the micro linear energy conversion system also needs to have bidirectional power flow capabilities, acting both as an energy source to provide energy to the linear motor and as an energy feedback device to absorb the energy generated by the linear motor. Summary of the Invention

[0004] In view of this, the present invention provides a dual-flow simplex composite energy storage system for a micro linear energy conversion system. Designed based on the characteristics of bidirectional energy flow and unidirectional operation of a micro linear energy conversion system, it can meet the requirements of bidirectional energy flow and achieve unidirectional energy operation in the same time period, thereby reducing disturbances and saving energy. The entire composite energy storage system has a simple structure, light weight, low cost, fast response speed, and reduced instantaneous current impact, which helps to improve the energy feeding efficiency of piston expansion while reducing the damage of instantaneous current to battery life.

[0005] The technical solution of the present invention is: a dual-current simplex composite energy storage system for a micro linear energy conversion system, comprising: an H-bridge PWM drive module, a dual-current simplex DC-DC power conversion module, and a supercapacitor-battery composite energy storage module;

[0006] The supercapacitor-battery composite energy storage module, the load, and the relay K are connected in series to form a loop. The H-bridge PWM drive module and the dual-current simplex DC-DC power conversion module are connected in parallel with the supercapacitor-battery composite energy storage module. A first filter capacitor C1 is connected in parallel between the H-bridge PWM drive module and the dual-current simplex DC-DC power conversion module, and a second filter capacitor C2 is connected in parallel between the dual-current simplex DC-DC power conversion module and the supercapacitor-battery composite energy storage module.

[0007] Preferably, the H-bridge PWM drive module includes: four transistor switches Q1, Q2, Q3, Q4 and four freewheeling diodes D1, D2, D3, D4; the four freewheeling diodes D1, D2, D3, D4 are connected in parallel across the four transistor switches Q1, Q2, Q3, Q4 respectively; the first transistor switch Q1 and the third transistor switch Q3 are connected in series to form a first branch, the second transistor switch Q2 and the fourth transistor switch Q4 are connected in series to form a second branch, and the first branch and the second branch are connected in parallel; one end of the linear energy conversion system is connected between the first transistor switch Q1 and the third transistor switch Q3, and the other end is connected between the second transistor switch Q2 and the fourth transistor switch Q4.

[0008] Preferably, the four freewheeling diodes D1, D2, D3, and D4 are all MOS-FET freewheeling diodes.

[0009] Preferably, the dual-current simplex DC-DC power conversion module includes: four transistor switches q1, q2, q3, and q4, an energy storage inductor L, and four freewheeling diodes d1, d2, d3, and d4; the four freewheeling diodes d1, d2, d3, and d4 are connected in parallel across the four transistor switches q1, q2, q3, and q4 respectively; the fifth transistor switch q1 and the seventh transistor switch q3 are connected in series to form the third branch, and the sixth transistor switch q2 and the eighth transistor switch q4 are connected in series to form the fourth branch; the third branch is connected in parallel with the H-bridge PWM drive module, and the fourth branch is connected in parallel with the supercapacitor-battery composite energy storage module; one end of the energy storage inductor L is connected between the fifth transistor switch q1 and the seventh transistor switch q3, and the other end is connected between the sixth transistor switch q2 and the eighth transistor switch q4.

[0010] Preferably, the four freewheeling diodes d1, d2, d3, and d4 are all MOS-FET freewheeling diodes.

[0011] Preferably, the supercapacitor-battery composite energy storage module includes: a ninth transistor switch S, a ninth freewheeling diode SD, a supercapacitor group SC, and a battery group BAT; the ninth freewheeling diode SD is connected in parallel across the ninth transistor switch S; the ninth transistor switch S is connected in series with the supercapacitor group SC, and this series circuit is connected in parallel with the battery group BAT.

[0012] Preferably, the supercapacitor-battery composite energy storage module includes: a ninth transistor switch S, a ninth freewheeling diode SD, a supercapacitor group SC, and a battery group BAT; the ninth freewheeling diode SD is connected in parallel across the ninth transistor switch S; the ninth transistor switch S is connected in series with the supercapacitor group SC, and this series circuit is connected in parallel with the battery group BAT.

[0013] Preferably, the freewheeling diode SD is a MOS-FET freewheeling diode.

[0014] Preferably, the supercapacitor bank SC is a micro supercapacitor bank.

[0015] Preferably, the battery pack BAT is a micro battery pack.

[0016] Beneficial effects:

[0017] 1. The composite energy storage system of the present invention has a simple overall structure, low cost, easy implementation, and is easy to modularize; it can realize bidirectional flow of electrical energy, serving as both an energy source to provide energy for a linear motor and an energy feedback device to absorb the energy generated by the linear motor; it fully utilizes the advantages of both supercapacitors and batteries, ensuring the energy density of the energy storage system while achieving instantaneous high-power input and output; simultaneously, it can suppress power fluctuations and stabilize voltage when the system switches between electric and power generation modes; furthermore, the boost charging circuit in the present invention can recover the induced electromotive force at low voltage to achieve maximum efficiency recovery of combustion expansion energy and improve the system's energy conversion efficiency.

[0018] 2. The specific design of the H-bridge PWM drive module in this invention can effectively utilize the H-bridge PWM drive module to realize bidirectional power flow between the supercapacitor and the MFP.

[0019] 3. The specific design of the dual-stream simplex DC-DC power conversion module in this invention can effectively utilize the dual-stream simplex DC-DC power conversion module to realize bidirectional power increase and decrease between the supercapacitor and the MFP; based on the working characteristic of the MFP's unidirectional energy flow in the same time period, this module is simplex, that is, the energy can only increase and decrease in one direction in the same time period, which can reduce disturbances and save energy.

[0020] 4. The specific design of the supercapacitor-battery composite energy storage module in this invention: 1) Utilizing the high energy density of the battery pack BAT, it provides the energy required by the linear motor for the MFP to operate in electric mode, and absorbs the energy generated by the linear motor in power generation mode; the battery pack BAT provides a stable power supply for the load.

[0021] 2) Utilizing the high power density of the supercapacitor bank (SC), it serves as a buffer unit for the battery bank (BAT) to directly absorb and release the instantaneous peak energy of the linear motor, maintaining a dynamic balance between stable input and output.

[0022] 5. The composite energy storage system of the present invention uses the switching functions of transistor switches Q1~Q4, q1~q4 and S to realize circuit control; it uses the peak-shaving and valley-filling functions of energy storage components such as freewheeling diodes D1~D4, d1~d4 and SD, energy storage inductor L and filter capacitors C1 and C2 to effectively smooth current and voltage. Attached Figure Description

[0023] Figure 1 This is a schematic diagram showing the connection between the composite energy storage system and the MFP involved in this invention.

[0024] Figure 2 This is a circuit diagram of the composite energy storage system involved in this invention.

[0025] Figure 3 This is a schematic diagram of the boost discharge process of the composite energy storage system involved in the present invention in electric mode. (a) The fifth transistor switch q1 is turned on and the seventh transistor switch q3 is turned off. (b) The fifth transistor switch q1 is turned off and the seventh transistor switch q3 is turned on.

[0026] Figure 4 This is a schematic diagram of the step-down charging process of the composite energy storage system involved in the present invention in the power generation mode. (a) The fifth transistor switch q1 is turned on and the seventh transistor switch q3 is turned off. (b) The fifth transistor switch q1 is turned off and the seventh transistor switch q3 is turned on.

[0027] Figure 5 This is a schematic diagram of the boost charging process of the composite energy storage system involved in the present invention in the power generation mode. (a) The eighth transistor switch q4 is turned on and the sixth transistor switch q2 is turned off. (b) The eighth transistor switch q4 is turned off and the sixth transistor switch q2 is turned on. Detailed Implementation

[0028] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0029] This embodiment provides a dual-current simplex composite energy storage system for a micro linear energy conversion system. It utilizes the high power density of supercapacitor banks and the high energy density of battery banks, and designs circuit modules using multiple transistor switches, freewheeling diodes, energy storage inductors, and filter capacitors. This system can meet the requirements of bidirectional energy flow, instantaneous high-power charging / discharging, and high-frequency input / output switching in the MFP, and effectively store and utilize the system's energy surplus. At the same time, it also has the effect of suppressing power fluctuations and stabilizing voltage during mode switching.

[0030] like Figure 1 As shown, the composite energy storage system includes: an H-bridge PWM drive module, a dual-current simplex DC-DC power conversion module, and a supercapacitor-battery composite energy storage module;

[0031] The supercapacitor-battery composite energy storage module, the load, and the relay K are connected in series to form a loop. The H-bridge PWM drive module and the dual-current simplex DC-DC power conversion module are connected in parallel with the supercapacitor-battery composite energy storage module. A first filter capacitor C1 is connected in parallel between the H-bridge PWM drive module and the dual-current simplex DC-DC power conversion module, and a second filter capacitor C2 is connected in parallel between the dual-current simplex DC-DC power conversion module and the supercapacitor-battery composite energy storage module.

[0032] In this embodiment, as Figure 2 As shown, the H-bridge PWM drive module includes: four transistor switches Q1, Q2, Q3, and Q4, and four freewheeling diodes D1, D2, D3, and D4; the four freewheeling diodes D1, D2, D3, and D4 are connected in parallel to the two ends of the four transistor switches Q1, Q2, Q3, and Q4 respectively; the first transistor switch Q1 and the third transistor switch Q3 are connected in series to form the first branch, the second transistor switch Q2 and the fourth transistor switch Q4 are connected in series to form the second branch, and the first branch and the second branch are connected in parallel; one end of the micro linear power conversion system (MFP) is connected between the first transistor switch Q1 and the third transistor switch Q3, and the other end is connected between the second transistor switch Q2 and the fourth transistor switch Q4.

[0033] In this embodiment, as Figure 2As shown, the dual-current simplex DC-DC power conversion module includes: four transistor switches q1, q2, q3, and q4, an energy storage inductor L, and four freewheeling diodes d1, d2, d3, and d4; the four freewheeling diodes d1, d2, d3, and d4 are connected in parallel to the two ends of the four transistor switches q1, q2, q3, and q4 respectively; the fifth transistor switch q1 and the seventh transistor switch q3 are connected in series to form the third branch, and the sixth transistor switch q2 and the eighth transistor switch q4 are connected in series to form the fourth branch. The third branch is connected in parallel with the H-bridge PWM drive module, and the fourth branch is connected in parallel with the supercapacitor-battery composite energy storage module; one end of the energy storage inductor L is connected between the fifth transistor switch q1 and the seventh transistor switch q3, and the other end is connected between the sixth transistor switch q2 and the eighth transistor switch q4, thereby connecting the third branch and the fourth branch.

[0034] In this embodiment, as Figure 2 As shown, the supercapacitor-battery composite energy storage module includes: a ninth transistor switch S, a ninth freewheeling diode SD, a supercapacitor group SC, and a battery group BAT; the ninth freewheeling diode SD is connected in parallel across the nine transistor switch S; the ninth transistor switch S is connected in series with the supercapacitor group SC, and this series circuit is connected in parallel with the battery group BAT.

[0035] In this embodiment, the four freewheeling diodes D1, D2, D3, and D4 are all MOS-FET freewheeling diodes.

[0036] In this embodiment, the four freewheeling diodes d1, d2, d3, and d4 are all MOS-FET freewheeling diodes.

[0037] In this embodiment, the freewheeling diode SD is a MOS-FET freewheeling diode.

[0038] In this embodiment, the supercapacitor bank SC is a miniature supercapacitor bank.

[0039] In this embodiment, the battery pack BAT uses a micro battery pack.

[0040] The working process of this composite energy storage system is as follows:

[0041] When the MFP is in the compression scavenging and closed compression stages, the battery pack (BAT) needs to supply power to the MFP, and the composite energy storage system is in electric mode. At this time, the MFP and the external load are both working loads, and the supercapacitor-battery composite energy storage module needs to be in boost discharge mode. Figure 3As shown, the fifth transistor switch q1 is turned on, and the first transistor switches Q1 and Q4 are also turned on. Chopping can be performed by controlling the on / off state of the seventh transistor switch q3. At the same time, the voltage of the supercapacitor bank SC and the armature current of the external linear motor are monitored. Based on the ideal piston trajectory and the changes in the external load, when high power is required, the ninth transistor switch S is turned on, so that the supercapacitor bank SC assists the battery bank BAT in releasing electrical energy to achieve instantaneous high-power discharge.

[0042] When the MFP is in the combustion, expansion work, and expansion gas exchange stages, it is in power generation mode. Therefore, the supercapacitor-battery composite energy storage module needs to operate in energy storage mode. Since the MFP's power generation voltage is a non-constant transient voltage, its peak voltage is reached in the early stage of piston expansion work, which is much higher than the charging voltage of the supercapacitor-battery composite energy storage module. Therefore, voltage reduction charging is required, such as... Figure 4 As shown, all four transistor switches Q1, Q2, Q3, and Q4 are open, and the induced current generated by the MFP flows along the D3-D2 direction. The fifth transistor switch q1 and the sixth transistor switch q2 are turned on, and the induced electromotive force charges the supercapacitor-battery composite energy storage module. Subsequently, the fifth transistor switch q1 is turned off and the seventh transistor switch q3 is turned on, so the energy previously stored in the energy storage inductor L is released, and the induced electromotive force continues to charge the supercapacitor-battery composite energy storage module. By repeatedly switching the fifth transistor switch q1 and the seventh transistor switch q3 on and off, the induced electromotive force is chopped and reduced to charge the supercapacitor-battery composite energy storage module.

[0043] When the MFP operates in the later stages of expansion and gas exchange, the piston speed decreases, thus its generation voltage decreases accordingly. Meanwhile, the terminal voltage of the supercapacitor bank (SC) has increased. When the induced electromotive force of the MFP falls below a certain value, this terminal voltage will severely affect the charging efficiency of the supercapacitor-battery hybrid energy storage module or even prevent the module from charging. Therefore, boost charging is required. Figure 5 As shown, all four transistor switches Q1, Q2, Q3, and Q4 are turned off, and the induced current generated by the MFP flows along the D3-D2 direction. First, the fifth transistor switch q1 and the eighth transistor switch q4 are kept on, and the induced electromotive force charges the energy storage inductor L. Subsequently, the eighth transistor switch q4 is turned off, and the sixth transistor switch q2 is turned on, so the induced electromotive force and the energy storage inductor L simultaneously charge the supercapacitor-battery composite energy storage module. This process is repeated to achieve the goal of boosting and chopping the induced electromotive force by controlling the on / off state of the eighth transistor switch q4 and the sixth transistor switch q2, thereby charging the MFP. The boost charging circuit can recover the low-voltage induced electromotive force to achieve the maximum efficiency recovery of combustion expansion energy.

[0044] In this embodiment, during the MFP power generation process, corresponding to buck charging and boost charging, the PWM duty cycle of the fifth transistor switch q1 and the eighth transistor switch q4 in the buck chopper circuit and boost chopper circuit can be adjusted respectively to control the output voltage during the power generation process. At the same time, the armature current of the linear motor can be controlled, thereby realizing the adjustment of the electromagnetic force of the linear motor.

[0045] In this embodiment, when the MFP encounters unstable operating conditions such as startup or misfire, the piston assembly needs to be reset to the bottom dead center. At this time, the linear motor is in reverse motoring mode, and its basic working principle is similar to that of forward motoring mode. The second transistor switch Q2 and the third transistor switch Q3 are kept on, and the boost chopper output is achieved by controlling the on and off of the seventh transistor switch Q3. Then, the control of the MFP armature current is achieved by controlling the duty cycle of the second transistor switch Q2 and the third transistor switch Q3.

[0046] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A dual-flow simplex composite energy storage system for a micro linear energy conversion system, characterized in that, include: H-bridge PWM drive module, dual-current simplex DC-DC power conversion module and supercapacitor-battery composite energy storage module; The supercapacitor-battery composite energy storage module, the load, and the relay K are connected in series to form a loop. The H-bridge PWM drive module and the dual-current simplex DC-DC power conversion module are connected in parallel with the supercapacitor-battery composite energy storage module. A first filter capacitor C1 is connected in parallel between the H-bridge PWM drive module and the dual-current simplex DC-DC power conversion module, and a second filter capacitor C2 is connected in parallel between the dual-current simplex DC-DC power conversion module and the supercapacitor-battery composite energy storage module. The H-bridge PWM drive module includes: four transistor switches Q1, Q2, Q3, and Q4, and four freewheeling diodes D1, D2, D3, and D4; the four freewheeling diodes D1, D2, D3, and D4 are connected in parallel across the four transistor switches Q1, Q2, Q3, and Q4 respectively; the first transistor switch Q1 and the third transistor switch Q3 are connected in series to form the first branch, the second transistor switch Q2 and the fourth transistor switch Q4 are connected in series to form the second branch, and the first branch and the second branch are connected in parallel; one end of the linear energy conversion system is connected between the first transistor switch Q1 and the third transistor switch Q3, and the other end is connected between the second transistor switch Q2 and the fourth transistor switch Q4; The dual-current simplex DC-DC power conversion module includes: four transistor switches q1, q2, q3, and q4; one energy storage inductor L; and four freewheeling diodes d1, d2, d3, and d4. The four freewheeling diodes d1, d2, d3, and d4 are connected in parallel across the four transistor switches q1, q2, q3, and q4, respectively. A fifth transistor switch q1 and a seventh transistor switch q3 are connected in series to form a third branch, and a sixth transistor switch q2 and an eighth transistor switch q4 are connected in series to form a fourth branch. The third branch is connected in parallel with the H-bridge PWM drive module, and the fourth branch is connected in parallel with the supercapacitor-battery composite energy storage module. One end of the energy storage inductor L is connected between the fifth transistor switch q1 and the seventh transistor switch q3, and the other end is connected between the sixth transistor switch q2 and the eighth transistor switch q4. The supercapacitor-battery composite energy storage module includes: a ninth transistor switch S, a ninth freewheeling diode SD, a supercapacitor group SC, and a battery group BAT; the ninth freewheeling diode SD is connected in parallel across the ninth transistor switch S; the ninth transistor switch S is connected in series with the supercapacitor group SC, and this series circuit is connected in parallel with the battery group BAT.

2. The dual-flow simplex composite energy storage system for the micro linear energy conversion system as described in claim 1, characterized in that, The four freewheeling diodes D1, D2, D3, and D4 are all MOS-FET freewheeling diodes.

3. The dual-flow simplex composite energy storage system for the micro linear energy conversion system as described in claim 1, characterized in that, The four freewheeling diodes d1, d2, d3, and d4 are all MOS-FET freewheeling diodes.

4. The dual-flow simplex composite energy storage system for the micro linear energy conversion system as described in claim 1, characterized in that, The freewheeling diode SD is a MOS-FET freewheeling diode.

5. The dual-flow simplex composite energy storage system for the micro linear energy conversion system as described in claim 1, characterized in that, The supercapacitor bank SC is a miniature supercapacitor bank.

6. The dual-flow simplex composite energy storage system for the micro linear energy conversion system as described in claim 1, characterized in that, The battery pack BAT uses a micro battery pack.

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