DC-to-AC boost circuit, power supply module based on DC-to-AC boost circuit and logging-while-drilling instrument

Abstract

The utility model discloses a DC-to-AC boost circuit, a power supply module based on the DC-to-AC boost circuit and a logging-while-drilling instrument, and the boost circuit enables two charging and discharging branches to present different states of charging, energy storage and discharging by controlling the on-off states of four switches in two sets of twin circuits; and when the charging and discharging branches are in a discharging state, the charging and discharging branches and the voltage of the battery pack are superposed and output to connection points of the second switch branches which are connected in parallel respectively, so that DC-to-AC boost output is realized. Based on the booster circuit power supply module, the number of batteries required by the power supply module can be reduced to a large extent, so that the purpose of saving space is achieved; meanwhile, the formed parallel oscillation circuit also has the effects of stabilizing the output voltage, improving the power factor of the whole system, reducing the apparent power demand of the power supply and protecting the circuit.

Description

Technical Field

[0001] This utility model belongs to the field of boost circuit technology, specifically relating to a DC-to-AC boost circuit, a power supply module based thereon, and a logging-while-drilling instrument. Background Technology

[0002] Logging While Drilling (LWD) is a real-time measurement system integrated into drilling tools. It simultaneously acquires downhole geological and engineering parameters during drilling, significantly improving the efficiency and safety of oil and gas exploration and development. LWD instruments are typically integrated inside or below the drill collar, close to the drill bit. This layout reduces interference from drilling fluids, such as obtaining more accurate formation information before mud invades the formation. The drill collar, as a crucial component of the drill string, provides mechanical support and protection for the LWD, preventing damage from vibration or high pressure. In horizontal wells or complex wellbore trajectories, the LWD works in conjunction with directional drill collars (with elbows or rotary steering systems) to adjust the tool face angle in real time, ensuring the wellbore trajectory meets design requirements.

[0003] With technological advancements, an increasing number of LWDs (Low-Drilling Drives) are adopting battery power to improve operational flexibility and safety. However, battery power increases the length of the drill collars, which are part of the drill string used to stabilize the drill bit and transmit torque. Their length directly impacts the flexibility of drilling operations. Longer drill collars make the drill string heavier and more difficult to maneuver flexibly in complex formations, especially in directional and horizontal drilling, where drill collar length is crucial for build-up performance (i.e., the ability to change the wellbore trajectory). Shorter drill collars allow for more precise control of the drill bit's direction, increasing the build-up rate and thus better adapting to changes in geological conditions, enabling finer wellbore trajectory control.

[0004] Drill collar length also affects other key performance indicators of drilling operations, such as: 1. Longer drill collars increase the total weight and friction of the drill string, potentially leading to power loss in the drilling rig and reducing drilling speed and efficiency; 2. Excessively long drill collars may affect the stability of the tool face (i.e., the measuring instruments and tools mounted on the drill collar), resulting in inaccurate measurement data and affecting the scientific basis of decision-making; 3. Longer drill collars increase the overall complexity of the drill string, potentially leading to more mechanical failure points, increasing maintenance costs and operational risks. Therefore, LWD (Long Drill Collar) components attached to drill collars also need to be miniaturized. Utility Model Content

[0005] To address the need for miniaturization of LWD (Logging While Drilling) systems, this invention proposes a DC-to-AC boost circuit, a power supply module based on it, and a logging-while-drilling instrument, thereby reducing the space required for the power supply module and achieving the goal of miniaturization of the LWD.

[0006] This utility model protects a DC-to-AC boost circuit, which includes two sets of twin circuits. Each set of twin circuits includes a first switch branch, a voltage divider branch, a charge-discharge branch, and a second switch branch connected in parallel. The two ends of these four branches are respectively connected to the positive and negative terminals of the battery pack. The first and second switch branches each include two switches connected in series and not closed at the same time. The connection point of the two switches in the first switch branch is also connected to the negative terminal of the battery pack through a current-limiting resistor.

[0007] The output voltage of the boost circuit is taken from the connection point of the two switches in the second switch branch of the two sets of twin circuits. By controlling the opening and closing state of the four switches in the two sets of twin circuits, the two charging and discharging branches present different states of charging, energy storage and discharging. When the charging and discharging branch is in the discharging state, it is superimposed with the battery pack voltage and output to the connection point of the second switch branch connected in parallel, thereby realizing the DC to AC boost output.

[0008] Specifically, the simplest form of the first and second charge / discharge branches is a capacitor.

[0009] Specifically, the two sets of twin circuits are the first twin circuit and the second twin circuit. The charging and discharging branch of the first twin circuit is denoted as the first charging and discharging branch, and the charging and discharging branch of the second twin circuit is denoted as the second charging and discharging branch. The output voltage terminals of the boost circuit are denoted as TK+ and TK-, respectively, where TK+ is taken from the first twin circuit and TK- is taken from the second twin circuit.

[0010] The positive terminal of the battery pack is connected to the voltage divider branch, the charge-discharge branch, and the second switch branch via a diode; the first switch branch of the first twin circuit includes a first and a second switch connected in series, and the second switch branch of the first twin circuit includes a third and a fourth switch connected in series; the first switch branch of the second twin circuit includes a seventh and a eighth switch connected in series, and the second switch branch of the second twin circuit includes a fifth and a sixth switch connected in series.

[0011] The boost circuit operates in the following eight different stages, exhibiting five different states:

[0012] L1, all switches from the first to the eighth are off, and the battery pack charges the first and second charge / discharge branches respectively;

[0013] L2, the first and eighth switches are turned on, and the rest of the switches are turned off. Due to the first switch being closed and the unidirectional conductivity of the diode, the first charge-discharge branch is in the energy storage state, while the second charge-discharge branch is still in the charging state.

[0014] L3, the first, third, sixth and eighth switches are turned on, and the rest of the switches are turned off. Since the third and sixth switches are turned on, the first charge-discharge branch discharges to the TK+ terminal and is superimposed with the positive voltage of the battery pack. At this time, the second charge-discharge branch is still in the charging state.

[0015] L4, with the first and eighth switches turned on and the remaining switches turned off, returns to the state of L2;

[0016] L5, all switches from the first to the eighth are open, that is, it returns to the state of L1;

[0017] L6, the second and seventh switches are turned on, and the other switches are turned off. Due to the seventh switch being turned on, and the unidirectional conductivity of the diode, the second charge-discharge branch is in the energy storage state, while the first charge-discharge branch is still in the charging state.

[0018] L7, the second, fourth, fifth and seventh switches are turned on, and the rest of the switches are turned off. Because the fourth and seventh switches are turned on, the second charge-discharge branch discharges to the TK- terminal, and at the same time, it is superimposed with the positive voltage of the battery pack. At this time, the first charge-discharge branch is still in the charging state.

[0019] With L8, the second and seventh switches are turned on, and the remaining switches are turned off, thus returning to the state of L6.

[0020] This utility model also protects a power supply module, including a battery pack and the aforementioned DC-to-AC boost circuit.

[0021] This utility model also protects a logging-while-drilling instrument that uses the above-mentioned power supply module, wherein the boost circuit is constructed in the form of an integrated circuit, which can save space to the maximum extent.

[0022] This invention provides a DC-to-AC boost circuit for miniaturizing LWD, which can significantly reduce the number of battery cells required for the power supply module, thereby saving space. At the same time, the parallel oscillation circuit also stabilizes the output voltage, improves the power factor of the entire system, reduces the apparent power demand of the power supply, and provides protection. Attached Figure Description

[0023] Figure 1 The DC-to-AC boost circuit diagram and its state 1 disclosed in Example 1;

[0024] Figure 2 The timing control logic for the DC-to-AC boost circuit disclosed in Example 1;

[0025] Figure 3 State 2 is the DC-to-AC boost circuit diagram disclosed in Example 1;

[0026] Figure 4 State 3 is the DC-to-AC boost circuit diagram disclosed in Example 1;

[0027] Figure 5 State four of the DC-to-AC boost circuit diagram disclosed in Example 1;

[0028] Figure 6State 5 of the DC-to-AC boost circuit diagram disclosed in Example 1;

[0029] Figure 7 This invention discloses a resistor value configuration scheme for a DC-to-AC boost circuit diagram. Detailed Implementation

[0030] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the present invention to the disclosed forms. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical applications of the present invention, and to enable those skilled in the art to understand the present invention and design various embodiments with various modifications suitable for a particular purpose.

[0031] Example 1

[0032] Figure 1 A specific form of the DC-to-AC boost circuit disclosed in this utility model is given, wherein the upper part is a first twin circuit and the lower part is a second twin circuit. The first and second twin circuits constitute a parallel oscillating circuit connected in parallel between TK+ and TK-.

[0033] Combination Figure 1 The first switch branch of the first twin branch includes the first switch Q1 and the second switch Q2; the second switch branch of the first twin branch includes the third switch Q3 and the fourth switch Q4; the first switch branch of the second twin branch includes the fifth switch Q5 and the sixth switch Q5; the second switch branch of the second twin branch includes the seventh switch Q7 and the eighth switch Q8. The first charge-discharge branch is capacitor C3, and the second charge-discharge branch is capacitor C6. The voltage divider branch uses the simplest form: a resistor.

[0034] The core objective of this embodiment is to control the opening and closing states of four switches in two sets of twin circuits so that the two charging and discharging branches exhibit different states of charging, energy storage, and discharging. When the charging and discharging branch is in the discharging state, it is superimposed with the battery pack voltage and output to the connection point of the second switch branch connected in parallel, thereby realizing the DC-to-AC boost output.

[0035] To achieve the above objectives, the timing control of switches Q1~Q8 is as follows: Figure 2 As shown, under this timing control logic, the boost circuit operates in eight different stages from L1 to L8, exhibiting five different states.

[0036] L1 and Q1~Q8 are all disconnected. See [link / reference] Figure 1 This is called state one.

[0037] Since Q3, Q4, Q7, and Q8 are all disconnected, there is no connection between TK+, TK- and the two sets of twin circuits. The two ends of capacitor C3 are connected to the positive terminal HV+ and negative terminal HV- of the battery pack via A and B, respectively. The two ends of capacitor C6 are connected to the positive terminal HV+ and negative terminal HV- of the battery pack via C and D, respectively. Therefore, in this state, the battery pack charges capacitors C3 and C6 respectively. The red arrow indicates the direction of current flow in the battery pack, and the same applies below.

[0038] L2, Q1, and Q8 are on, the rest of the switches are off. See below. Figure 3 This is called state two.

[0039] Because Q1 is turned on, the voltage divider branch is short-circuited, and the current flow in the first twin circuit is as follows: Figure 3 As shown by the red arrow above, due to the unidirectional conductivity of the diode, capacitor C3 is in an energy storage state; since Q8 is closed, the current-limiting resistor is short-circuited, and the current flow in the second twin circuit is as follows. Figure 3 As shown by the red arrow below, capacitor C6 is still charging.

[0040] L3, Q1, Q8, Q3, and Q6 are on, the rest of the switches are off. See below. Figure 4 This is called state three.

[0041] Since Q1 and Q3 are both conducting, capacitor C3 discharges to the TK+ terminal, which is superimposed on the forward voltage of the battery pack. This results in the TK+ terminal voltage being the sum of the forward voltage of the battery pack and the discharge voltage of capacitor C3. The current flow between TK+ and HV+ is as follows: Figure 4 As shown by the green arrow above; with Q6 and Q8 conducting simultaneously, the current flow between TK- and HV- is as follows. Figure 4 As indicated by the green arrow below, capacitor C6 is still charging at this point.

[0042] When switches L4, Q1, and Q8 are turned on, and the remaining switches are turned off, the system returns to state two.

[0043] L5 and Q1~Q8 are all disconnected, which means returning to state one.

[0044] L6, Q2, and Q7 are on, the rest of the switches are off. See below. Figure 5 This is called state four.

[0045] Because Q7 is turned on, the voltage divider branch is short-circuited, and the current flow in the second twin circuit is as follows: Figure 5 As shown by the red arrow below, due to the unidirectional conductivity of the diode, capacitor C6 is in an energy storage state; since Q2 is closed, the current-limiting resistor is short-circuited, and the current flow in the first twin circuit is as follows. Figure 5 As indicated by the red arrow above, capacitor C3 is still charging.

[0046] L7, Q2, Q7, Q4, and Q5 are on, while the remaining switches are off. See [link / reference]. Figure 6 This is called state five.

[0047] Since Q2 and Q4 are both conducting simultaneously, capacitor C6 discharges to terminal TK-, which is superimposed on the forward voltage of the battery pack. This results in the voltage at terminal TK- being the sum of the forward voltage of the battery pack and the discharge voltage of capacitor C6. The current flow between TK+ and HV- is as follows: Figure 6 As shown by the green arrow above; with Q5 and Q7 conducting simultaneously, the current flow between TK- and HV+ is as follows. Figure 6 As indicated by the green arrow below, capacitor C3 is still charging at this point.

[0048] With L8, Q2, and Q7 turned on, and the remaining switches turned off, the system returns to state four.

[0049] It's easy to see that L4, L5, and L8 are transition stages, ensuring a safe transition between different states. By designing the parameters of each component in the boost circuit, the boost circuit can output the ±21.6V AC voltage required by LWD. For example, if the battery pack provides 10.8V, the boost circuit, through parameter design of each component, achieves a voltage multiplication effect, thus outputting a ±21.6V AC voltage. Here, the battery pack can use three lithium-ion or lithium iron phosphate batteries connected in series, with a nominal voltage of 3.6V~3.7V per cell, for a total voltage of 10.8V~11.1V. Compared to six lithium batteries connected in series, three lithium batteries connected in series save 50% of space.

[0050] For example, Figure 1 The selection of resistors in the boost circuit shown can be referenced. Figure 7 As shown. Because 2.7M*2 is much larger than 10K*3, the voltage divider branch can receive most of the battery pack voltage, allowing the potential difference across capacitors C3 / C6 to approach 10.8V. Meanwhile, the 10K*3 has a much larger resistance than the short-circuit branch, causing the potential of capacitors C3 / C6 during energy storage to be superimposed on the positive terminal of the power supply, resulting in a voltage of nearly 21.6V during discharge. Furthermore, due to the large resistance of 2.7M*2, it acts as an open circuit during the energy storage phase of capacitors C3 / C6 and when the load is connected, thus allowing for full energy release and reduced losses.

[0051] The first and second twin circuits form a parallel oscillating circuit connected in parallel between TK+ and TK-, and also have the following functions:

[0052] 1. By adjusting the parameters of the oscillation circuit, resonance can be achieved at a specific frequency, thereby stabilizing the output voltage, reducing voltage fluctuations, and smoothing out voltage fluctuations.

[0053] 2. Parallel oscillating circuits can effectively filter out high-frequency noise and harmonic components in the power supply through their frequency selectivity. The harmonic suppression capability of the oscillating circuit helps to improve the purity of the output voltage and reduce the impact on the load.

[0054] 3. Parallel oscillating circuits also have the function of reactive power compensation. They can introduce reactive components into the load current that are opposite to those of inductive or capacitive loads, thereby improving the power factor of the entire system and reducing the apparent power demand of the power supply.

[0055] 4. In addition, parallel oscillating circuits also have the function of protection circuits. For example, parallel oscillating circuits can absorb excess voltage under overvoltage conditions, preventing excessively high voltage from acting directly on the load, thereby protecting the load equipment from damage; when a short circuit occurs in the load, the parallel oscillating circuit can respond quickly, limiting the growth of the short circuit current and providing a certain degree of protection.

[0056] Furthermore, this boost circuit is relatively simple and does not require magnetic components, making it relatively easy to design and manufacture; since it does not use a bulky transformer, the boost circuit can be designed in a smaller size, thus meeting the miniaturization requirements of LWD; compared to transformer boost circuits, charge pump boost circuits generate less electromagnetic interference.

[0057] Example 2

[0058] A power supply module includes a battery pack and a DC-to-AC boost circuit disclosed in Embodiment 1.

[0059] Example 3

[0060] A logging-while-drilling instrument is powered by the power supply module disclosed in Example 1, wherein the switch can be a MOSFET and the entire circuit is constructed in the form of an integrated circuit to save space to the maximum extent.

[0061] Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art and related fields based on the embodiments of this utility model without inventive effort should fall within the protection scope of this utility model.

Claims

1. A DC-to-AC boost circuit, characterized in that, It includes two sets of twin circuits. Each set of twin circuits includes a first switch branch, a voltage divider branch, a charge-discharge branch, and a second switch branch connected in parallel. The two ends of these four branches are respectively connected to the positive and negative terminals of the battery pack. The first and second switch branches each include two switches connected in series and not closed at the same time. The connection point of the two switches in the first switch branch is also connected to the negative terminal of the battery pack through a current-limiting resistor. The output voltage of the boost circuit is taken from the connection point of the two switches in the second switch branch of the two sets of twin circuits. By controlling the opening and closing state of the four switches in the two sets of twin circuits, the two charging and discharging branches present different states of charging, energy storage and discharging. When the charging and discharging branch is in the discharging state, it is superimposed with the battery pack voltage and output to the connection point of the second switch branch connected in parallel, thereby realizing the DC to AC boost output.

2. The DC-to-AC boost circuit according to claim 1, characterized in that, The two sets of twin circuits are the first twin circuit and the second twin circuit. The charging and discharging branch of the first twin circuit is denoted as the first charging and discharging branch, and the charging and discharging branch of the second twin circuit is denoted as the second charging and discharging branch. The output voltage terminals of the boost circuit are denoted as TK+ and TK-, respectively, where TK+ is taken from the first twin circuit and TK- is taken from the second twin circuit. The positive terminal of the battery pack is connected to the voltage divider branch, the charge-discharge branch, and the second switch branch via a diode; the first switch branch of the first twin circuit includes a first and a second switch connected in series, and the second switch branch of the first twin circuit includes a third and a fourth switch connected in series; the first switch branch of the second twin circuit includes a seventh and a eighth switch connected in series, and the second switch branch of the second twin circuit includes a fifth and a sixth switch connected in series. The boost circuit operates in the following eight different stages, exhibiting five different states: L1, all switches from the first to the eighth are off, and the battery pack charges the first and second charge / discharge branches respectively; L2, the first and eighth switches are turned on, and the rest of the switches are turned off. Due to the first switch being closed and the unidirectional conductivity of the diode, the first charge-discharge branch is in the energy storage state, while the second charge-discharge branch is still in the charging state. L3, the first, third, sixth and eighth switches are turned on, and the rest of the switches are turned off. Since the third and sixth switches are turned on, the first charge-discharge branch discharges to the TK+ terminal and is superimposed with the positive voltage of the battery pack. At this time, the second charge-discharge branch is still in the charging state. L4, with the first and eighth switches turned on and the remaining switches turned off, returns to the state of L2; L5, all switches from the first to the eighth are open, that is, it returns to the state of L1; L6, the second and seventh switches are turned on, and the other switches are turned off. Due to the seventh switch being turned on, and the unidirectional conductivity of the diode, the second charge-discharge branch is in the energy storage state, while the first charge-discharge branch is still in the charging state. L7, the second, fourth, fifth and seventh switches are turned on, and the rest of the switches are turned off. Because the fourth and seventh switches are turned on, the second charge-discharge branch discharges to the TK- terminal, and at the same time, it is superimposed with the positive voltage of the battery pack. At this time, the first charge-discharge branch is still in the charging state. With L8, the second and seventh switches are turned on, and the remaining switches are turned off, thus returning to the state of L6.

3. The DC-to-AC boost circuit according to claim 1 or 2, characterized in that, The first and second charge / discharge branches include capacitors.

4. The DC-to-AC boost circuit according to claim 3, characterized in that, The switch uses a MOSFET.

5. The DC-to-AC boost circuit according to claim 4, characterized in that, It is constructed using integrated circuits.

6. A power supply module, characterized in that, It includes a battery pack and a DC-to-AC boost circuit as described in any one of claims 1-5.

7. A logging-while-drilling instrument, characterized in that, The power supply module described in claim 6 is used for power supply.

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