Linear bidirectional power supply

Abstract

The invention discloses a linear bidirectional power supply which comprises a voltage acquisition and error amplification module, a signal reverse module, a power tube Q1 and a power tube Q2, the power tube Q1 and the power tube Q2 are the same in type, the drain electrode of the power tube Q1 is connected with the positive electrode of the power supply, and the grid electrode of the power tube Q1 is connected with the voltage acquisition and error amplification module and the signal reverse module. The source electrode of the power tube Q1 is connected with the drain electrode of the power tube Q2 and one end of a tested product, the grid electrode of the power tube Q2 is connected with the signal reverse module, and the source electrode of the power tube Q2 is connected with the negative electrode of the power supply and the other end of the tested product. According to the invention, the two power tubes of the same type are combined with the voltage acquisition and error amplification module and the signal reverse module, so that bidirectional current flow is realized, the structure is simple, the cost is low, high-precision voltage regulation and current limiting functions are supported, the charging and discharging states of the battery can be simulated, and the device is suitable for BMS testing and charging and discharging testing of battery / capacitor products.

Description

Technical Field

[0001] The present invention relates to the technical field of direct current power supplies, and in particular to a linear bidirectional power supply in which current can flow in both directions, which is used to simulate the charging and discharging state of a battery, and is particularly suitable for the testing link of a battery management system (BMS). The linear bidirectional power supply can simulate the working state of a single battery cell, multiple battery cells connected in series, or a battery pack, and supports charging and discharging tests on products such as capacitors and batteries. Background Art

[0002] The battery simulation scheme in the prior art mostly adopts a DC power supply as the voltage supply of the entire battery pack, connects multiple identical resistors in series to the positive and negative poles of the power supply, and simulates the voltage on each battery cell by resistor voltage division.

[0003] Currently, there are many active balancing BMS solutions. Since the current method cannot charge, it is impossible to simulate the state of the battery when charging, and it is impossible to test the active balancing BMS.

[0004] There is also an intelligent solution that uses two PMOS and two NMOS in series to achieve control.

[0005] This type of solution has the following drawbacks:

[0006] 1. Unable to adjust the cell voltage independently: The voltage of all cells is composed of the total voltage and a fixed resistance divider. When the total voltage is adjusted, all cells change synchronously and are adjusted together. It is impossible to adjust a single cell separately.

[0007] 2. Limited accuracy: The control accuracy is not high, and the voltage control accuracy is limited by the total power supply accuracy and the voltage divider resistance.

[0008] 3. Since it is obtained by resistor voltage division, the BMS cannot obtain a large balancing current when doing voltage balancing and can only simulate the voltage.

[0009] 4. Unable to simulate charging status: The resistor voltage division scheme can only provide voltage signals, and cannot realize bidirectional current of charging and discharging, resulting in the inability to meet the test requirements of active balancing BMS;

[0010] 5. Complex structure: The existing active solution uses multiple different types of power tubes (such as a combination of PMOS and NMOS), which leads to complex circuits and high costs. Installation errors are prone to occur during production, resulting in a decrease in yield rate. In addition, only one of the four power tubes is working at the same time, with a utilization rate of only 25%.

[0011] Therefore, there is an urgent need for a high-precision power supply solution with simple structure, low cost, support for bidirectional current and independent adjustment. Summary of the invention

[0012] The main purpose of the present invention is to propose a linear bidirectional power supply in which current can flow in both directions, aiming to solve the problems in the prior art such as difficulty in independent regulation of battery cells, low control accuracy, inability to simulate charging and discharging states, and low power tube utilization.

[0013] To achieve the above-mentioned purpose, the present invention provides a linear bidirectional power supply, comprising: a voltage acquisition and error amplification module, a signal inversion module, a power tube Q1 and a power tube Q2, wherein the power tube Q1 and the power tube Q2 are of the same type, the drain of the power tube Q1 is connected to the positive electrode of the power supply, the gate of the power tube Q1 is connected to the voltage acquisition and error amplification module and the signal inversion module, the source of the power tube Q1 is connected to the drain of the power tube Q2 and one end of the product under test, the gate of the power tube Q2 is connected to the signal inversion module, and the source of the power tube Q2 is connected to the negative electrode of the power supply and the other end of the product under test.

[0014] A further technical solution of the present invention is that the voltage acquisition and error amplification module includes an operational amplifier AMP1 and a capacitor C1, the signal inversion module includes an operational amplifier AMP2, a resistor R1 and a resistor R2, the gate of the power tube Q1 is connected to one end of the capacitor C1, pin 3 of the operational amplifier AMP1 and one end of the resistor R1, the other end of the capacitor C1 is connected to pin 1 of the operational amplifier AMP1, the other end of the resistor R1 is connected to one end of the resistor R2 and pin 1 of the operational amplifier AMP2, and the other end of the resistor R2 is connected to pin 3 of the operational amplifier AMP2 and the gate of the power tube Q2.

[0015] A further technical solution of the present invention is that it also includes an operational amplifier AMP3, an operational amplifier AMP4, an operational amplifier AMP5, an operational amplifier AMP6, a capacitor C2, a capacitor C3, a diode D1, a diode D2, a resistor R3, a resistor R4, a resistor R5, a resistor R6 and a resistor R7, one end of the capacitor C2 is connected to the pin 1 of the operational amplifier AMP3, and the other end is connected to the cathode of the diode D1 and the pin 3 of the operational amplifier AMP3, the anode of the diode D1 is connected to one end of the resistor R3 and the gate of the power tube Q1, the other end of the resistor R3 is connected to one end of the capacitor C1, the pin 3 of the operational amplifier AMP1 and one end of the resistor R1, and one end of the resistor R4 is connected to the operational amplifier AMP 5 and one end of the resistor R5, the other end of the resistor R5 is connected to pin 3 of the operational amplifier AMP5, one end of the capacitor C3 and pin 1 of the operational amplifier AMP4, the other end of the capacitor C3 is connected to pin 3 of the operational amplifier AMP4 and the cathode of the diode D2, the anode of the diode D2 is connected to one end of the resistor R6 and the gate of the power tube Q2, the other end of the resistor R6 is connected to pin 3 of the operational amplifier AMP2 and the other end of the resistor R2, pin 2 of the operational amplifier AMP6 is connected to the source of the power tube Q2 and one end of the resistor R7, and pin 1 of the operational amplifier AMP6 is connected to the other end of the resistor R7 and the other end of the product under test.

[0016] A further technical solution of the present invention is that both the power tube Q1 and the power tube Q2 are NMOS power tubes.

[0017] A further technical solution of the present invention is that both the power tube Q1 and the power tube Q2 are PMOS tubes.

[0018] A further technical solution of the present invention is that the power tube Q1 and the power tube Q2 are both IGBTs.

[0019] The linear bidirectional power supply of the present invention can achieve the following technical effects through the above technical solution:

[0020] 1. Simplified structure: only two power tubes of the same type are needed, reducing costs by 50% and improving yield.

[0021] 2. High utilization rate: The utilization rate of power tubes is increased to 50% (the existing technology is 25%).

[0022] 3. Bidirectional current control: supports charging and discharging mode switching to meet the testing requirements of active / passive balancing BMS.

[0023] 4. High precision and flexibility: The voltage of a single battery cell can be adjusted independently, multiple battery cells can be simulated in series, and various power tube types (such as PMOS and IGBT) can be adapted. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0025] Figure 1 It is a system block diagram of a preferred embodiment of the linear bidirectional power supply of the present invention;

[0026] Figure 2 It is a schematic diagram of a linear bidirectional power supply charge and discharge mode switching circuit of the present invention;

[0027] Figure 3 It is a schematic diagram of a linear bidirectional power supply current limiting function expansion circuit of the present invention.

[0028] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] In order to solve the problems of difficulty in independent adjustment of battery cells, low control accuracy, inability to simulate charge and discharge states, and low power tube utilization in the prior art, the present invention proposes a solution that can simulate various working conditions such as battery charging, discharging, and static state, and solve the testing requirements under various current BMS schemes. It can simulate a battery cell or multiple battery cells in series, and even simulate the working state of a whole battery pack. It can be applied to the test link of BMS to test whether various working conditions of BMS are within the design range, simulate various states of the battery, and each battery cell can be adjusted independently with very high accuracy. The charge and discharge current can be achieved in a very large range by means of parallel power circuits. The present invention is chargeable and dischargeable, so it can be applied to both passively balanced BMS and actively balanced BMS system tests. The present invention aims to simulate batteries in the field of BMS testing, and can be used as a charging and discharging device to test the charging and discharging of batteries, capacitors and other similar products.

[0031] Specifically, the present invention proposes a linear bidirectional power supply, please refer to Figure 1 , Figure 1 It is a system block diagram of a preferred embodiment of the linear bidirectional power supply of the present invention, showing the voltage acquisition, error amplification, signal reversal and power tube connection relationship. The preferred embodiment of the linear bidirectional power supply of the present invention includes a voltage acquisition and error amplification module, a signal reversal module, a power tube Q1 and a power tube Q2. The power tube Q1 and the power tube Q2 are of the same type, and the two ends of the tested product are the output stages of the linear bidirectional power supply.

[0032] The drain of the power tube Q1 is connected to the positive pole of the power supply, the gate of the power tube Q1 is connected to the voltage acquisition and error amplification module and the signal inversion module, the source of the power tube Q1 is connected to the drain of the power tube Q2 and one end of the product under test, the gate of the power tube Q2 is connected to the signal inversion module, and the source of the power tube Q2 is connected to the negative pole of the power supply and the other end of the product under test.

[0033] This embodiment has only two power tubes, thus reducing production costs and increasing utilization from 25% to 50%. The two power tubes are of the same model, so there will be no installation errors, which can effectively improve production yield. This embodiment has high precision, can be intelligently adjusted, and current and bidirectional flow, thereby effectively solving the test requirements required by active balancing BMS, truly simulating various working states of a battery cell, and can also be used as a charge and discharge test equipment for similar products such as capacitors and batteries.

[0034] In this embodiment, the voltage acquisition and error amplification module is used to acquire the output voltage and compare it with the set value, and generate an error signal to control the conduction state of the power tube.

[0035] The signal inversion module inverts the error signal to switch the charge and discharge mode.

[0036] The power tube Q1 and the power tube Q2 use two power tubes of the same type, such as NMOS tubes or PMOS tubes, to control the output current and the absorption current respectively.

[0037] The working principle of this embodiment is as follows:

[0038] 1. Discharge mode: When the voltage of the product under test is lower than the set value, the error signal drives the power tube Q1 to turn on, the power tube Q2 to turn off, and the power supply outputs current.

[0039] 2. Charging mode: When the voltage of the product under test is higher than the set value, the error signal reversely drives the power tube Q2 to turn on, the power tube Q1 to turn off, and the power supply absorbs current.

[0040] 3. Current limiting function: The power tube Q1 and the power tube Q2 are current limited and adjusted through the current control signal to realize automatic switching between constant voltage and current limiting.

[0041] The voltage acquisition and error amplification module of this embodiment acquires the output voltage as a feedback signal, compares it with the set signal, thereby obtaining a control output signal, and connects this signal to the Q1 output current power tube control stage above, thereby controlling the output voltage.

[0042] The voltage acquisition and error amplification module is connected to the input stage of the signal inversion module, and the output stage of the signal inversion module is connected to the control stage of the Q2 current absorption power tube below, thereby controlling the voltage at the output end.

[0043] This embodiment uses two power tubes Q1 and Q2 of the same type to form the power part of the output current and the absorption current. When the output current is output, the output voltage is compared with the set voltage through the voltage acquisition and error amplification module, and the error signal generated is used to control the power tube Q1, thereby controlling the conduction degree of the power tube Q1, so that the output voltage can be stabilized at the set required value. At this time, the control level signal of the power tube Q2 is the reverse voltage of the control level signal of the power tube Q1, so the power tube Q2 is in the off state. When the voltage of the product under test is higher than the set voltage, the signal output by the voltage acquisition and error amplification module is a negative value, thereby turning off the power tube Q1. At this time, the power tube Q2 will be converted into a positive value through the signal inversion module, so that the power tube Q2 is turned on, so that the entire system becomes an absorption current and can be stabilized at the set voltage.

[0044] For further information, please refer to Figure 2 In this embodiment, the voltage acquisition and error amplification module includes an operational amplifier AMP1 and a capacitor C1, the signal inversion module includes an operational amplifier AMP2, a resistor R1 and a resistor R2, the gate of the power tube Q1 is connected to one end of the capacitor C1, pin 3 of the operational amplifier AMP1 and one end of the resistor R1, the other end of the capacitor C1 is connected to pin 1 of the operational amplifier AMP1, the other end of the resistor R1 is connected to one end of the resistor R2 and pin 1 of the operational amplifier AMP2, and the other end of the resistor R2 is connected to pin 3 of the operational amplifier AMP2 and the gate of the power tube Q2.

[0045] This embodiment uses two NMOS tubes as main power devices. The voltage collection and error amplification module collects the output voltage through the operational amplifier AMP1, generates an error signal after comparing it with the set value, and controls the power tube Q1 to be turned on.

[0046] The error signal is processed by the signal inversion module (operational amplifier AMP2) to control the power tube Q2 to achieve charging and discharging mode switching.

[0047] It should be noted that this embodiment performs error amplification by collecting the signal at the output end and the voltage control signal. Taking the operational amplifier AMP1 as an example, the output voltage can be collected by combining multiple operational amplifiers, and then error amplification is achieved on the operational amplifier AMP1. Alternatively, one operational amplifier can be used to simultaneously achieve the effects of voltage collection and error amplification.

[0048] In this embodiment, the output stage of the operational amplifier AMP1 is connected to the operational amplifier AMP2, and the output signal of the operational amplifier AMP1 is inverted by the operational amplifier AMP2. The signal inversion effect can also be achieved by other inverters.

[0049] In this embodiment, the operational amplifier AMP1 outputs a control stage for controlling the power tube Q1 , and controls the conduction state of the power tube Q1 so that the voltage at both ends of the product under test is controlled by the voltage control signal.

[0050] In this embodiment, the operational amplifier AMP2 outputs a control stage for controlling the power tube Q2, and controls the conduction state of the power tube Q2 so that the voltage at both ends of the product under test is controlled by the voltage control signal.

[0051] When the voltage of the product under test is lower than the voltage control signal, the power tube Q1 will be controlled to turn on and the power tube Q2 will be turned off to achieve output current.

[0052] When the voltage of the product under test is higher than the voltage control signal, the power tube Q1 will be controlled to be turned off and the power tube Q2 will be turned on, thereby achieving current absorption.

[0053] For further information, please refer to Figure 3 , Figure 3It is a schematic diagram of the current limiting function expansion circuit of the linear bidirectional power supply of the present invention, showing the integration method of the current and error amplification module. In this embodiment, the linear bidirectional power supply also includes an operational amplifier AMP3, an operational amplifier AMP4, an operational amplifier AMP5, an operational amplifier AMP6, a capacitor C2, a capacitor C3, a diode D1, a diode D2, a resistor R3, a resistor R4, a resistor R5, a resistor R6 and a resistor R7, one end of the capacitor C2 is connected to the pin 1 of the operational amplifier AMP3, and the other end is connected to the cathode of the diode D1 and the pin 3 of the operational amplifier AMP3, the anode of the diode D1 is connected to one end of the resistor R3 and the gate of the power tube Q1, the other end of the resistor R3 is connected to one end of the capacitor C1, the pin 3 of the operational amplifier AMP1 and one end of the resistor R1, and one end of the resistor R4 is connected to the operational amplifier AMP3. Pin 1 of amplifier AMP5 and one end of resistor R5, the other end of resistor R5 is connected to pin 3 of operational amplifier AMP5, one end of capacitor C3 and pin 1 of operational amplifier AMP4, the other end of capacitor C3 is connected to pin 3 of operational amplifier AMP4 and the cathode of diode D2, the anode of diode D2 is connected to one end of resistor R6 and the gate of power tube Q2, the other end of resistor R6 is connected to pin 3 of operational amplifier AMP2 and the other end of resistor R2, pin 2 of operational amplifier AMP6 is connected to the source of power tube Q2 and one end of resistor R7, and pin 1 of operational amplifier AMP6 is connected to the other end of resistor R7 and the other end of the product under test.

[0054] In this embodiment, a current acquisition circuit (such as a series resistor or a Hall sensor) is connected to the control input stage of the power tube Q1 and the power tube Q2. The current signal is compared with the set value in the error amplifier (i.e., operational amplifier AMP3 and operational amplifier AMP4), and automatic switching between constant voltage and current limiting is achieved through competition logic.

[0055] In this embodiment, the power tube Q1 and the power tube Q2 are connected to the current control circuit at the control input stage, thereby adding the function of current limiting input and output.

[0056] Specifically, Figure 3 As shown, in this embodiment, the operational amplifier AMP6 is used to collect the voltage of the resistor connected in series in the loop to obtain the current collection signal. The loop current can also be collected by other methods, such as Hall, mutual inductance, etc.

[0057] In this embodiment, the current acquisition signal and the output current control signal are error amplified on the operational amplifier AMP3 (one operational amplifier can also be used to achieve the effects of current acquisition and error amplification at the same time). The signal after competition between the operational amplifier AMP3 and the operational amplifier AMP1 controls the power tube Q1, thereby realizing automatic switching between constant voltage and current limiting of the power tube Q1.

[0058] In this embodiment, the current acquisition signal is reversed by the operational amplifier AMP5 and the output current control signal is error amplified on the operational amplifier AMP4 (it is also possible to directly reverse the current acquisition signal and then perform error amplification on the operational amplifier AMP4), and the signal after the competition between the operational amplifier AMP4 and the operational amplifier AMP2 controls the power tube Q2, so as to realize the automatic switching between constant voltage and current limiting of the power tube Q2. It is also possible to use one operational amplifier to realize the effects of current acquisition and error amplification at the same time.

[0059] In this embodiment, the power tube Q1 and the power tube Q2 are of the same type, for example, both are NMOS power tubes, or both are PMOS tubes, or both are IGBTs. Figure 2 and Figure 3 When the NMOS tube shown is replaced with a PMOS tube or an IGBT, only the polarity of the control-stage signal needs to be adjusted, and the other modules remain unchanged.

[0060] The present invention realizes bidirectional current flow by combining two same-type power tubes with a voltage acquisition and error amplification module and a signal inversion module. It has a simple structure and low cost, supports high-precision voltage regulation and current limiting functions, can simulate the battery charging and discharging state, and is suitable for BMS testing and charging and discharging testing of battery / capacitor products.

[0061] In summary, the linear bidirectional power supply of the present invention can achieve the following technical effects through the above technical solution:

[0062] 1. Simplified structure: only two power tubes of the same type are needed, reducing costs by 50% and improving yield.

[0063] 2. High utilization rate: The utilization rate of power tubes is increased to 50% (the existing technology is 25%).

[0064] 3. Bidirectional current control: supports charging and discharging mode switching to meet the testing requirements of active / passive balancing BMS.

[0065] 4. High precision and flexibility: The voltage of a single battery cell can be adjusted independently, multiple battery cells can be simulated in series, and various power tube types (such as PMOS and IGBT) can be adapted.

[0066] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A linear bidirectional power supply, characterized in that: include: A voltage acquisition and error amplification module, a signal inversion module, a power tube Q1 and a power tube Q2, wherein the power tube Q1 and the power tube Q2 are of the same type, the drain of the power tube Q1 is connected to the positive pole of the power supply, the gate of the power tube Q1 is connected to the voltage acquisition and error amplification module and the signal inversion module, the source of the power tube Q1 is connected to the drain of the power tube Q2 and one end of the product under test, the gate of the power tube Q2 is connected to the signal inversion module, and the source of the power tube Q2 is connected to the negative pole of the power supply and the other end of the product under test.

2. The linear bidirectional power supply according to claim 1, characterized in that: The voltage acquisition and error amplification module includes an operational amplifier AMP1 and a capacitor C1, the signal inversion module includes an operational amplifier AMP2, a resistor R1 and a resistor R2, the gate of the power tube Q1 is connected to one end of the capacitor C1, pin 3 of the operational amplifier AMP1 and one end of the resistor R1, the other end of the capacitor C1 is connected to pin 1 of the operational amplifier AMP1, the other end of the resistor R1 is connected to one end of the resistor R2 and pin 1 of the operational amplifier AMP2, and the other end of the resistor R2 is connected to pin 3 of the operational amplifier AMP2 and the gate of the power tube Q2.

3. The linear bidirectional power supply according to claim 2, characterized in that: It also includes an operational amplifier AMP3, an operational amplifier AMP4, an operational amplifier AMP5, an operational amplifier AMP6, a capacitor C2, a capacitor C3, a diode D1, a diode D2, a resistor R3, a resistor R4, a resistor R5, a resistor R6 and a resistor R7, one end of the capacitor C2 is connected to the pin 1 of the operational amplifier AMP3, and the other end is connected to the cathode of the diode D1 and the pin 3 of the operational amplifier AMP3, the anode of the diode D1 is connected to one end of the resistor R3 and the gate of the power tube Q1, the other end of the resistor R3 is connected to one end of the capacitor C1, the pin 3 of the operational amplifier AMP1 and one end of the resistor R1, one end of the resistor R4 is connected to the pin 1 of the operational amplifier AMP5 and the gate of the power tube Q1, and one end of the resistor R5, the other end of the resistor R5 is connected to pin 3 of the operational amplifier AMP5, one end of the capacitor C3 and pin 1 of the operational amplifier AMP4, the other end of the capacitor C3 is connected to pin 3 of the operational amplifier AMP4 and the cathode of the diode D2, the anode of the diode D2 is connected to one end of the resistor R6 and the gate of the power tube Q2, the other end of the resistor R6 is connected to pin 3 of the operational amplifier AMP2 and the other end of the resistor R2, pin 2 of the operational amplifier AMP6 is connected to the source of the power tube Q2 and one end of the resistor R7, and pin 1 of the operational amplifier AMP6 is connected to the other end of the resistor R7 and the other end of the product under test.

4. The linear bidirectional power supply according to any one of claims 1 to 3, characterized in that: The power tube Q1 and the power tube Q2 are both NMOS power tubes.

5. The linear bidirectional power supply according to any one of claims 1 to 3, characterized in that: The power tube Q1 and the power tube Q2 are both PMOS tubes.

6. The linear bidirectional power supply according to any one of claims 1 to 3, characterized in that: The power tube Q1 and the power tube Q2 are both IGBTs.

Images