CN116526597A - Feedback current control device, charger and overhead working truck - Google Patents

Abstract

The invention relates to the technical field of engineering machinery, and discloses a feedback current control device, a charger and an overhead working truck. The control device is arranged in the charger and comprises: a first switch module; a second switch module; a capacitor, which is a capacitance within the charger; and a control module, which is a control module in the charger and is used for: when the feedback current characterization parameter indicates that the feedback current exists, the charging parameter of the capacitor is smaller than the preset charging parameter, and the state parameter of the battery indicates that the lithium precipitation risk exists, the first switch module is controlled to conduct the power supply circuit where the first switch module is located in a one-way mode, and the second switch module is controlled to conduct the circuit where the capacitor is located, so that the feedback current is captured by the capacitor. The control device is arranged in the charger, and the capacitor and the control module in the charger are ingeniously adopted as components of the control device, so that the lithium precipitation risk can be avoided, the occupied space and the cost additionally required by the control device can be saved, and the heat dissipation performance of the control device is good.

Description

Feedback current control device, charger and overhead working truck

Technical Field

The invention relates to the technical field of engineering machinery, in particular to a feedback current control device, a charger and an overhead working truck.

Background

For an electrically driven overhead working truck using a lithium ion power battery, a large number of experimental results show that when the temperature is lower than 0 ℃, the pulse feedback current can cause large-area lithium precipitation of the negative electrode plate. Meanwhile, under special conditions, when the high-altitude operation vehicle is in a full-power state and moves down a long slope, the reverse power generation current generated by the motor drive system can charge the lithium battery, so that the risk of overcharging the lithium battery is caused, and further lithium is separated from the battery. The two kinds of lithium precipitation can cause the capacity of the power battery to be reduced, lithium dendrites can be generated by severe lithium precipitation, and the lithium dendrites penetrate through a diaphragm to cause internal short circuit. If a large area short circuit occurs, there is a risk of thermal runaway. Therefore, it is necessary to take powerful measures to avoid the risk of low-temperature pulse charging or overcharging.

The existing feedback current control devices are all independent additional devices, and the additional cost of the whole machine is increased more. The independent feedback current control device has complex circuit, occupies larger assembly space of the whole machine, and has more fault points. In fact, the space available on an aerial vehicle is very limited, the cost control requirements are high, and there is also a high requirement for the reliability of the equipment due to the manned work.

Disclosure of Invention

The invention aims to provide a feedback current control device, a charger and an overhead working truck, wherein the feedback current control device is arranged in an original charger, and a capacitor and a control device configured by the charger are ingeniously adopted as component parts of the feedback current control device, so that the lithium precipitation risk caused by low-temperature pulse charging or overcharging can be avoided, the occupation space and cost additionally required by the feedback current control device can be saved, the external wiring points are reduced, and the reliability of the whole device is improved. And, because the heat dissipation area of the charger shell is large and the heat dissipation performance is good, the contact area between the feedback current control device and the air is large, so the heat dissipation performance of the feedback current control device is good and the reliability is high.

In order to achieve the above object, a first aspect of the present invention provides a feedback current control device provided in a charger, the feedback current control device comprising: the first switch module is positioned on a power supply circuit from the battery to the driver; a second switch module; a capacitor configured by the charger for charging the battery, the capacitor and the second switch module being located on a first current capture circuit; and a control module configured for the charger to control the control module to charge the battery, for performing the operations of: receiving a feedback current characterization parameter, a charging parameter of the capacitor and a state parameter of the battery; and under the condition that the feedback current characterization parameter indicates that the feedback current exists on the power supply circuit, the charging parameter of the capacitor is smaller than a preset charging parameter, and the state parameter of the battery indicates that the lithium precipitation risk exists on the battery, the power supply circuit is conducted unidirectionally by controlling the first switch module so as to inhibit the feedback current from charging the battery, and the first current capturing circuit is conducted by controlling the second switch module so as to capture the feedback current by the capacitor.

Preferably, the feedback current control device further includes: a third switch module; and the energy dissipation device and the third switch module are positioned on the second current capturing circuit, and correspondingly, the control module is further used for unidirectionally conducting the power supply circuit by controlling the first switch module so as to prohibit the feedback current from charging the battery and conducting the second current capturing circuit by controlling the third switch module so as to capture the feedback current by the energy dissipation device when the feedback current characterization parameter indicates that the feedback current exists on the power supply circuit, the charging parameter of the capacitor is larger than or equal to the preset charging parameter and the state parameter of the battery indicates that the battery has a lithium precipitation risk.

Preferably, the energy dissipation device is a braking resistor, and the braking resistor is connected with the shell of the charger through an insulating heat conducting material.

Preferably, the control module is further configured to determine that the capacitor fails in a case where the first current capturing circuit is turned on by controlling the second switching module, or to receive a temperature of the energy consumer in a case where the charging parameter of the capacitor does not continuously increase, and determine that the energy consumer fails in a case where the temperature of the energy consumer does not continuously increase.

Preferably, the control module is further configured to, if the feedback current characterization parameter indicates that there is a feedback current on the power supply circuit but the state parameter of the battery indicates that there is no risk of lithium precipitation of the battery, perform the following operations: and controlling the first switch module to conduct the power supply circuit bidirectionally so as to charge the battery through the feedback current.

Preferably, the control module is further configured to, in case the state parameter of the battery indicates that the battery is not at risk of lithium precipitation, perform the following operations: the power supply circuit is turned on bidirectionally by controlling the first switching module, and the first current capturing circuit is turned on by the second switching module to charge the battery by the capacitor.

Preferably, the feedback current characterization parameter indicates that there is feedback current on the power supply circuit, including: the difference between the voltage at one end of the driver and the voltage at one end of the battery on the power supply circuit is larger than a preset voltage; or the current on the power supply circuit is larger than a preset current.

Preferably, the state parameter of the battery indicates that the battery is at risk of lithium precipitation comprises: the temperature of the battery is less than or equal to a preset temperature; or the SOC of the battery is greater than or equal to a preset SOC.

Through the technical scheme, the feedback current control device is creatively arranged in the charger, and the capacitor and the control device configured by the charger are ingeniously adopted as component parts of the feedback current control device, so that lithium precipitation risks caused by low-temperature pulse charging or overcharging can be avoided, the occupied space and cost additionally required by the feedback current control device can be saved, external wiring points are reduced, and the reliability of the whole device is improved. In addition, the heat dissipation area of the charger shell is large, and the heat dissipation performance is good, so that the contact area between the feedback current control device and the air is large, and the heat dissipation performance of the feedback current control device is good.

The second aspect of the present invention also provides a charger, the charger comprising: the feedback current control device.

Specific details and benefits of the charger provided by the embodiments of the present invention can be found in the above description of the feedback current control device, and are not repeated here.

The third aspect of the present invention also provides an aerial work vehicle comprising: the charger.

Specific details and benefits of the aerial vehicle provided by the embodiments of the present invention can be found in the above description of the feedback current control device, and are not repeated here.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate the invention and together with the description serve to explain, without limitation, the invention. In the drawings:

FIG. 1 is a schematic diagram of a feedback current control device according to an embodiment of the invention; and

fig. 2 is a flowchart of a process performed by the feedback current control device according to an embodiment of the present invention.

Detailed Description

The following describes specific embodiments of the present invention in detail with reference to the drawings. It should be understood that the detailed description and specific examples, while indicating and illustrating the invention, are not intended to limit the invention.

Before describing various embodiments of the present invention, a brief description of a charger for an overhead working truck will be provided.

The charger 1 may convert the ac mains voltage into a dc voltage required by the battery, thereby charging the battery. In charging, the charger 1 performs voltage/power conversion mainly through the AC/DC charging module 140. The charger 1 includes: the capacitor is used for rectifying and filtering the DC output end when the battery is charged; a communication module (e.g., CAN communication module 110) for transmitting related information about battery status, failure, etc., transmitted from a Battery Management System (BMS), as shown in fig. 1; and a control means (e.g., CPU) for performing charge control of the battery according to the battery state.

The above embodiments are based on the existing charger 1, by improving the charger 1, three switch modules and energy consumers (such as brake resistors) are built in the charger 1, so that the charger 1 can normally control charging (with a charging mode), and simultaneously control the opening and closing of the current capturing circuit according to certain conditions, so that under the condition of low temperature or other conditions that the battery is not allowed to be charged, the current generated by regenerative braking is blocked, the current is prevented from entering the battery, and the current is consumed through the preset capacitor absorption or preset brake resistor (with a feedback current absorption mode) inside the charger 1.

Fig. 1 is a schematic structural diagram of a feedback current control device according to an embodiment of the invention. As shown in fig. 1, the feedback current control device 10 is disposed in the charger 1, and the feedback current control device 10 may include: a first switch module 20 located on a power supply circuit from the battery 2 to the driver 3; a second switch module 30; a capacitor 40, wherein the capacitor 40 is a capacitor configured by the charger 1 for charging the battery 2, and the capacitor 40 and the second switch module 30 are located on a first current capturing circuit; and a control module 50, the control module 50 being a control module configured for the charger 1 for controlling charging of the battery 2.

Wherein the first switch module 20 (for example, MOS transistor) is connected in series to the positive total power bus between the driver 3 and the battery 2; and the second switch module 30 (for example, MOS transistor) is connected in series to the capacitor 40 and the negative power bus of the battery 2. In the case that the first switch module 20 and the second switch module 30 are both MOS transistors, the MOS transistors may each include a dedicated control chip to control unidirectional or bidirectional conduction of the circuit in which they are located. And the MOS tube can adopt single or multiple redundant designs, and can be combined in parallel or in series in corresponding circuits when the multiple redundant designs are adopted.

In one embodiment, the control module 50 is configured to: receiving a feedback current characterization parameter, a charging parameter of the capacitor 40, and a state parameter of the battery 2; and in case that the feedback current characterization parameter indicates that there is a feedback current on the power supply circuit, the charging parameter of the capacitor 40 is smaller than a preset charging parameter, and the state parameter of the battery indicates that the battery 2 is at risk of lithium precipitation, unidirectionally conducting the power supply circuit by controlling the first switch module 20 to prohibit the feedback current from charging the battery 2, and conducting the first current capturing circuit by controlling the second switch module 30 to capture the feedback current by the capacitor 40.

Wherein the feedback current characterization parameter indicates that there is a feedback current on the power supply circuit may include: the difference between the voltage at one end of the driver 3 and the voltage at one end of the battery 2 on the power supply circuit is greater than a preset voltage (for example, 0.3V); or the current on the power supply circuit is larger than a preset current.

Wherein the charging parameters of the capacitor may include: voltage or SOC. Accordingly, the preset charging parameter may be a first specific charging parameter (e.g., a first specific voltage value or a first specific SOC value).

Wherein the state parameter of the battery indicates that the battery 2 is at risk of lithium precipitation may include: the temperature of the battery 2 is less than or equal to a preset temperature (e.g., 0 ℃); or the SOC of the battery 2 is greater than or equal to a preset SOC (e.g., 95%).

Specifically, for example, the charger 1 has a voltage sensor 80 built therein, for detecting voltages at a front end (e.g., point a) and a rear end (e.g., point B) of the first switch module 20 (e.g., MOS transistor). When the voltage of the point B is 0.3V higher than the voltage of the point A, the feedback current is judged to be generated; according to the temperature and the SOC of the battery 2 transmitted by the BMS, judging whether the battery has lithium precipitation risk: if the temperature of the battery 2 is less than or equal to a preset temperature (e.g., 0 ℃) or the SOC of the battery 2 is greater than or equal to a preset SOC (e.g., 95%), it indicates that the battery 2 is at risk of lithium precipitation; meanwhile, a voltage sensor 90 may be further disposed in the charger 1, for detecting the voltage across the capacitor 40 (i.e. the voltage of the capacitor 40), so as to determine whether the state of the capacitor 40 is suitable for absorbing the feedback current. For example, when the voltage across the capacitor 40 is lower than the first predetermined voltage value, the feedback current can be absorbed by the capacitor 40, specifically: the feedback current is disabled from charging the battery 2 by controlling the first switching module 20 (e.g., MOS transistor) to unidirectionally turn on the power supply circuit, and the feedback current is absorbed by the capacitor 40 by controlling the second switching module 30 (e.g., MOS transistor) to turn on the first current capturing circuit. When the voltage across the capacitor 40 reaches or exceeds said first predetermined voltage value, charging of the capacitor is not allowed, and the feedback current is absorbed by a power resistor, as described in detail below.

The capacitor 40 is self-charged by the charger itself, and is mainly used for rectifying and filtering the DC output terminal during charging in the prior art. In this embodiment, the capacitor 40 may be used to absorb the feedback energy to store the electrical energy. Meanwhile, the voltage across the capacitor 40 can be detected in real time to determine whether the capacitor is full. The capacitor 40 may be one or more capacitors, and when a plurality of capacitors are used, the plurality of capacitors may be connected in parallel or in series.

In an embodiment, the control module 50 is further configured to, if the feedback current characterization parameter indicates that there is feedback current on the power supply circuit but the state parameter of the battery indicates that the battery 2 is not at risk of lithium precipitation, perform the following operations: the power supply circuit is bi-directionally turned on by controlling the first switching module 20 to charge the battery 2 by the feedback current.

That is, for example, in the case that the B-point voltage is higher than the a-point voltage by a preset voltage (for example, 0.3V) (i.e., there is a feedback current on the power supply circuit), the temperature of the battery is greater than the preset temperature (for example, 0 ℃) and the SOC of the battery is greater than or equal to the preset SOC (for example, 95%) (i.e., there is no risk of lithium precipitation of the battery 2), the power supply circuit is bi-directionally turned on by controlling the first switch module 20 (for example, MOS transistor) to charge the battery 2 by the feedback current.

More preferably, the control module 50 is also configured to receive a current allowable charging current of the battery 2. Wherein the current allowable Charge current may be determined according to a current SOC (State of Charge) of the battery 2. Accordingly, the control module 50 is further configured to perform the following operations in a case where the B-point voltage is higher than the a-point voltage by a preset voltage (e.g., 0.3V), the temperature of the battery is greater than the preset temperature (e.g., 0 ℃) and the SOC of the battery is greater than or equal to a preset SOC (e.g., 95%): bi-directionally switching on the power supply circuit by controlling the first switching module 20; and controlling the driver 3 to charge the battery 2 with the current allowable charging current and through the power supply circuit by controlling the second switching module 30 to turn on the first current capturing circuit and by controlling the on-off time of the second switching module 30 (or by controlling the third switching module 60 to turn on the second current capturing circuit and by controlling the on-off time of the third switching module 60).

More specifically, in the case that the motor 4 generates a larger feedback current and the battery 2 is charged without generating a danger of lithium precipitation, the control module 50 (e.g., CPU) may control the Pulse Width Modulation (PWM) duty ratio by adopting a PI control algorithm, so as to control the on-off time of the second switch module 30 or the third switch module 60 (e.g., MOS transistor), so as to control the accurate shunt of the feedback current, so as to ensure that the charging current on the power supply circuit is equal to the current allowable charging current of the battery (may be determined according to the actual requirement, and may be a preset percentage of the current maximum current allowable charging current corresponding to the current SOC). Therefore, the embodiment can charge the battery according to the current allowable charging current (as close as possible to the current maximum current allowable charging current but not exceeding the current maximum current allowable charging current), and the redundant feedback energy is consumed through the capacitor or the resistor on the current capturing circuit, so that the overcharge phenomenon is avoided, and the service life of the battery is prolonged.

In an embodiment, the control module 50 is further configured to, if the state parameter of the battery indicates that the battery is not at risk of lithium precipitation, perform the following operations: the power supply circuit is turned on bi-directionally by controlling the first switching module 20, and the first current capturing circuit is turned on by the second switching module 30 to charge the battery 2 by the capacitor 40.

That is, when the temperature of the battery 2 is higher than the preset temperature and the SOC of the battery 2 is smaller than the preset SOC, the capacitor 40 is controlled to charge the battery 2 to consume the electric energy in the capacitor 40. Of course, in the present embodiment, in the case where the charging parameter (for example, voltage or SOC) of the capacitor 40 is smaller than the second specific charging parameter (for example, the second specific voltage value or the second specific SOC value), it is indicated that the capacitor is in the low capacity state, and the battery 2 can be charged by the charger 1. Wherein the second specific voltage value is much smaller than the first specific voltage value, and the second specific SOC value is much smaller than the first specific SOC value.

In one embodiment, the feedback current control device 10 may further include: a third switch module 60; and an energy consumer 70, the energy consumer 70 and the third switch module 60 being located on a second current capture circuit.

Accordingly, the control module 50 is further configured to, when the feedback current characterization parameter indicates that there is a feedback current on the power supply circuit, the charging parameter of the capacitor 40 is greater than or equal to the preset charging parameter, and the state parameter of the battery indicates that the battery 2 is at risk of lithium precipitation, control the first switch module 20 to conduct the power supply circuit unidirectionally to prohibit the feedback current from charging the battery 2, and control the third switch module 60 to conduct the second current capturing circuit to capture the feedback current by the energy consumer 70.

The energy dissipation device 70 may be a braking resistor, and the braking resistor is connected with the housing of the charger 1 through an insulating heat conducting material. That is, when the resistor is adopted for absorption, the braking resistor can convert electric energy into heat energy to consume, and the braking resistor is connected with the shell of the charger by adopting an insulating heat conducting material. And, the braking resistor may be one or more resistors, wherein when the braking resistor is a plurality of resistors, the plurality of resistors may be connected in parallel or in series.

Wherein the third switch module 60 (e.g., MOS transistor) and the energy consumer (e.g., brake resistor) are connected in parallel between the positive and negative total power buses between the driver 3 and the battery 2. In the case that the third switch module 60 is a MOS transistor, the MOS transistor may include a dedicated control chip to control unidirectional or bidirectional conduction of the circuit in which the MOS transistor is located. And the MOS tube can adopt single or multiple redundant designs, and can be combined in parallel or in series in corresponding circuits when the multiple redundant designs are adopted.

Specifically, when the voltage sensor 80 detects that the B-point voltage is 0.3V higher than the a-point voltage, it can be determined that the feedback current is generated; when the temperature of the battery 2 is less than or equal to a preset temperature (e.g., 0 ℃) or the SOC of the battery 2 is greater than or equal to a preset SOC (e.g., 95%), it indicates that the battery 2 is at risk of lithium precipitation; meanwhile, when the voltage sensor 90 detects that the voltage across the capacitor 40 (i.e., the voltage of the capacitor 40) is higher than or equal to the first predetermined voltage value, the feedback current may be absorbed through the energy consumer 70 (e.g., a brake resistor). The method comprises the following steps: the feedback current is disabled from charging the battery 2 by controlling the first switching module 20 (e.g., MOS transistor) to unidirectionally turn on the power supply circuit, and is consumed by a braking resistor by controlling the third switching module 60 (e.g., MOS transistor) to turn on the second current capturing circuit.

The embodiment can absorb redundant feedback energy through the brake resistor to convert electric energy into heat energy. Through the resistance and the power of the braking resistor are matched, the braking resistor can meet the braking distance of the motor 4, can meet the braking current which is not absorbed by the motor 4 in a short time, and can meet the heat dissipation requirement of the whole machine. The parameter matching of the braking resistance can be calculated by an energy conversion formula. A temperature sensor 130 may be mounted on the brake resistor to detect the temperature of the brake resistor.

The regenerative braking feedback current of the travelling motor of the overhead working truck is generated in two working conditions, namely active braking in normal operation. In the second type of downhill working condition, the running motor rotor speed exceeds the rotating speed of the motor synchronous magnetic field due to the inertia action of gravitational potential energy of the whole machine, the rotating direction of electromagnetic torque generated by the rotor winding is opposite to the rotating direction of the rotor, and the motor is in a braking state and a power generation state. The feedback current control device in the charger can control and detect the feedback current generated under any working condition, so that the situation that the feedback current enters the lithium battery for charging or overcharging at low temperature is effectively avoided, and the lithium separation risk of the battery is further avoided.

The improved and upgraded charger is based on the existing charger technology, fewer parts are added to form a feedback current control device, and therefore the low-temperature pulse charging or overcharging risk problem of the lithium battery overhead working truck driven by a motor is well solved on the basis of very little cost increase. Charging regenerative braking feedback current into the battery at normal temperature (when the battery does not have lithium precipitation risk); when the battery has the lithium precipitation risk, the capacitor is preferentially used for absorbing regenerative braking feedback current, and once the capacitor is full of electricity (for example, the SOC is more than 95%), the resistor is used for absorbing redundant feedback energy. The motor braking device not only can meet the normal motor braking function, but also can avoid the low-temperature pulse charging or overcharging of the lithium battery. The current is recovered through the lithium battery at normal temperature, so that the electric energy consumption is reduced, and the energy conservation and the improvement of the cruising ability of the equipment are facilitated.

The control module 50 is further configured to determine that the capacitor 40 is malfunctioning in case the first current capturing circuit is turned on by controlling the second switching module 30, or to receive the temperature of the energy consumer 70 in case the charging parameter of the capacitor 40 is not continuously increased, and to determine that the energy consumer 70 is malfunctioning in case the temperature of the energy consumer 70 is not continuously increased, by controlling the third switching module 60 to turn on the second current capturing circuit.

That is, in the above control process of absorbing the feedback current, the fault of the current feedback control device can be checked by the voltage sensor 90 or the temperature sensor 130, and the checking principle is as follows: for example, the voltage across the capacitor 40 is collected by the voltage sensor 90, and when the voltage does not reach the first specific voltage value (the capacitor is not full), the feedback current is absorbed by the capacitor 40, and the voltage across the capacitor 40 should continuously increase. If the voltage across the capacitor 40 does not increase continuously, it indicates that the element consuming the feedback current has a fault, and the charger may send the fault to the overall control device 5 via the bus, so as to alert the feedback current sink to failure. When the voltage reaches the first specific voltage value (the capacitor is full), the resistor is adopted to absorb the feedback current, and the temperature of the resistor is continuously increased. If the temperature of the resistor is not continuously increased, the resistor which is an element consuming the feedback current is failed, and at the moment, the charger can send the failure to the whole machine control device 5 through the bus to remind the failure of the feedback current absorbing device.

In one embodiment, the feedback current control device may further include: the CAN communication module 110, the CAN communication module 110 is a CAN communication module configured inside the charger 1. The CAN communication module 110 may communicate with the BMS 6 and the overall control device 5, and the communication content mainly includes information such as temperature information of the battery, state of charge (SOC), whether charging is allowed, and current allowing charging.

In one embodiment, the feedback current control device may further include: a bypass switch 120, the bypass switch 120 being connected in parallel with the first switching device 20, and correspondingly the control module 50 being further configured to control the bypass switch 120 to be closed to conduct the power supply circuit when the first switching device 20 fails. Thus, emergency use of the device can be ensured. The bypass switch 120 may send an instruction to the charger 1 through the overall control device 5, and the control module 50 (e.g. CPU) in the charger 1 controls whether the bypass switch 120 is activated or not.

In one embodiment, the feedback current control device may further include: the temperature sensor 130 may be used to detect the temperature of an element such as an energy consumer (e.g., a brake resistor) in real time. For example, whether the temperature of the brake resistor is ultrahigh in the process of absorbing the brake feedback current can be monitored in real time, whether the temperature of other elements in the brake resistor is ultrahigh in the process of charging can also be monitored in real time, and the fault of the ultrahigh temperature can be sent to the complete machine control device 5 through a bus.

The control circuit power supply in the charger 1 is separated from the power circuit power supply, wherein the control circuit power supply comprises a control device (such as a CPU) main chip power supply, a sensor power supply, a CAN communication module power supply and the like; and the power circuit power supply comprises a power supply of each switch module (such as a MOS tube), a charging input power supply, a charging output power supply, a bypass switch power supply and the like. When the whole machine is electrified or the charger 1 is plugged in the commercial power, firstly, the control circuit power supply is electrified, the control device (such as a CPU) starts self-checking, and after the self-checking has no fault, the power circuit power supply is connected.

The charger 1 is also internally provided with a signal filter circuit and a power isolation circuit so as to improve the anti-interference performance and the control accuracy.

A charging relay is preset in the charger 1, and the charging relay is used for starting a charging mode. When the commercial ac power on the charger 1 is turned on, a control module (e.g., CPU) inside the charger 1 passes the self-test, and the relay is started to switch the charger 1 to the charging mode.

The process performed by the feedback current control apparatus will now be described by taking fig. 2 as an example.

As shown in fig. 2, the feedback current control device may perform a process including steps S201 to S208.

Step S201, the device is powered on.

If the charger is on mains ac, the control module 50 starts a self-test; or if the charger is not powered on by the mains ac power supply, the complete machine is powered on and the control module 50 also starts self-checking.

Step S202, the control module self-checks and judges whether the state is normal, if so, step S203 is executed; otherwise, step S208 is performed.

If the charger is connected with a commercial alternating current power supply, the self-checking process mainly comprises the following steps: 1) AC/DC charging module 140 status and fault detection; 2) Detecting the state of a charging relay; 3) And detecting faults of the communication module. Then, after the self-checking is normal, the relay is sucked and charged, and normal charging is carried out until the battery is full.

If the charger is not connected with the commercial alternating current power supply, the whole machine is electrified, and the self-checking process mainly comprises the following steps: 1) Detecting the state of a charging relay; 2) The first switch module 20 (e.g. MOS transistor) is in a state and fault detection, the initial state is a point a to point B on, and point B is blocked; 3) The second switch module 30 (e.g., MOS transistor) is in an off state and fault detection, and the initial state is off; 4) The third switch module 60 (e.g., MOS transistor) is in an off state and fault detection, the initial state; 5) Detecting faults of the communication module; 6) Detecting the state of a bypass switch, wherein the initial state is disconnection; 7) Detecting faults of energy consumers (such as brake resistors), detecting normal connection of the energy consumers (such as brake resistors), and conducting faults; 8) And (5) detecting capacitance faults.

Step S203, the battery data and the voltages at the two ends of the first switch module are obtained, and if the voltages indicate that the feedback current is generated, whether the battery has a lithium precipitation risk is judged, if yes, step S204 is executed, and if not, step S207 is executed.

After the self-detection is abnormal, if the CPU detects that the voltage of the point B at the right end of the first switch module 20 is 0.3V higher than that of the point A at the left end, the CPU indicates that feedback current is generated on the power supply circuit. And reading battery data (including the temperature of the battery (cell) and the electric quantity (SOC) of the battery) sent by the BMS through the bus, and if the temperature of the battery is lower than a preset temperature (e.g., 0 ℃) or the SOC is higher than a preset SOC (e.g., 95%), indicating that the battery is at risk of lithium precipitation, performing step S204. Otherwise, the battery temperature is higher than the preset temperature (e.g., 0 ℃) and the SOC is lower than the preset SOC (e.g., 95%), indicating that the battery is not at risk of lithium precipitation, and step S207 is performed.

Step S204, judging whether the capacitor state allows the absorption of the feedback current, if so, executing step S205; otherwise, step S206 is performed.

If the voltage of the capacitor does not reach the first specific voltage value, the capacitor is indicated to be allowed to absorb the feedback current.

In step S205, capacitance absorption control is performed.

The first switch module 20 (e.g., MOS transistor) is controlled to start the reverse blocking function, so that the reverse current is prohibited from flowing to the battery through the first switch module 20 (e.g., MOS transistor), and meanwhile, the conducting function of the second switch module 30 (e.g., MOS transistor) is opened, so that the feedback current generated by braking can be absorbed through the capacitor.

Step S206, resistance energy consumption control is executed.

The first switch module 20 (e.g., MOS transistor) is controlled to start the reverse blocking function, so that the reverse current is prohibited from flowing to the battery through the first switch module 20 (e.g., MOS transistor), and at the same time, the conducting function of the third switch module 60 (e.g., MOS transistor) is turned on, so that the feedback current generated by braking can be consumed through the braking resistor.

In the process of absorbing feedback current, a capacitor is preferentially adopted for absorption. And detecting the state of the capacitor in real time, and absorbing the voltage of the capacitor end by adopting the capacitor as long as the voltage of the capacitor end does not reach the first specific voltage value. The capacitor may store the absorbed feedback current until the capacity is saturated.

Step S207, battery absorption control is performed.

If the battery temperature is higher than the preset temperature (e.g. 0 ℃) and the SOC is lower than the preset SOC (e.g. 95%), the CPU does not detect the voltage across the first switch module 20 (e.g. MOS transistor) any more under this condition, and controls the first switch module 20 (e.g. MOS transistor) to be both on in two directions (at this time, both the second switch module 30 and the third switch module 60 are in the off state), the feedback current generated by braking flows to the battery through the first switch module 20 (e.g. MOS transistor), and the battery absorbs the braking current to achieve the effect of energy recovery.

Step S208, a failure is sent.

If the self-detection is abnormal, the control module 50 sends the fault to the whole machine control device 5 through a bus, and the control device 5 alarms and limits the whole machine action.

The control module 50 can perform fault detection for the first switch module 20, the second switch module 30, and the third switch module 60 during the whole braking process. Specifically, the states of the first, second, and third switch modules 20, 30, and 60 under different conditions mainly include the following.

1) Initial state (after the self-test is completed).

The first switch module 20 is turned on bidirectionally, i.e., a to B is turned on, B to a is turned on; the second switch module 30 and the third switch module 60 are both disconnected bidirectionally;

2) Capacitance absorption control-battery temperature is lower than a preset temperature (e.g., 0 ℃) or SOC is higher than a preset SOC (e.g., 95%), the right terminal B voltage of the first switch module 20 is 0.3V higher than the left terminal a voltage thereof, and the voltage of the capacitor is lower than a first specific voltage value.

The first switch module 20 is turned on unidirectionally, i.e., a to B is conductive and B to a is non-conductive; the second switch module 30 is conducted bidirectionally; (and the third switch module 60 is both open).

3) Resistance consumption control-battery temperature is lower than a preset temperature (e.g., 0 ℃) or SOC is higher than a preset SOC (e.g., 95%), and the right terminal B voltage of the first switch module 20 is 0.3V higher than the left terminal a voltage thereof and the voltage of the capacitor is higher than the first specific voltage value.

The first switch module 20 is turned on unidirectionally, i.e., a to B is conductive and B to a is non-conductive; (the second switch module 30 is both open); the third switch module 60 is both conductive.

4) The battery powers the driver-the battery temperature is lower than a preset temperature (e.g., 0 ℃) or the SOC is higher than a preset SOC (e.g., 95%), and the difference between the right terminal B voltage and the left terminal a voltage of the first switch module 20 is less than 0.3V.

The first switch module 20 is turned on bidirectionally; the second switch module 30 and the third switch module 60 are both bidirectionally disconnected.

5) Battery absorption control-battery temperature is higher than a preset temperature (e.g., 0 ℃) or SOC is lower than a preset SOC (e.g., 95%), and the right terminal B voltage of the first switch module 20 is 0.3V higher than the left terminal a voltage thereof and the voltage of the capacitor is higher than the first specific voltage value.

The first switch module 20 is turned on bidirectionally; the second switch module 30 and the third switch module 60 are both bidirectionally disconnected.

In summary, the invention creatively sets the feedback current control device in the charger, and skillfully adopts the capacitor and the control device configured by the charger as the component parts of the feedback current control device, thereby not only avoiding the lithium precipitation risk caused by low-temperature pulse charging or overcharging, but also saving the occupation space and cost additionally required by the feedback current control device, reducing the external wiring points and improving the reliability of the whole device. In addition, the heat dissipation area of the charger shell is large, and the heat dissipation performance is good, so that the contact area between the feedback current control device and the air is large, and the heat dissipation performance of the feedback current control device is good.

An embodiment of the present invention further provides a charger 1, where the charger 1 may include: the feedback current control device 10.

Specific details and benefits of the charger provided by the embodiments of the present invention can be found in the above description of the feedback current control device, and are not repeated here.

An embodiment of the present invention also provides an overhead working truck, which may include: the charger 1.

The aerial vehicle is further provided with a complete machine control device 5, as shown in fig. 1. The complete machine control device 5 is configured with a CAN communication module for transmitting complete machine action operation signals to the driver 3, the usual operation control signals coming from the handle (mainly including forward, backward, steering, braking, etc. of the device), wherein the braking signals are mainly by releasing the handle or pushing the handle in the opposite direction. The CAN communication module CAN receive information about battery state, failure, etc., transmitted from the battery BMS, and CAN also receive information about the state, capacitance state, temperature of brake resistance, etc., of each switch module transmitted from the charger 1. And corresponding actions, such as fault alarm, limiting actions and the like, are executed according to the information and the threshold strategy.

Specific details and benefits of the aerial vehicle provided by the embodiments of the present invention can be found in the above description of the feedback current control device, and are not repeated here.

The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the scope of the technical concept of the present invention, and all the simple modifications belong to the protection scope of the present invention.

In addition, the specific features described in the above embodiments may be combined in any suitable manner without contradiction. The various possible combinations of the invention are not described in detail in order to avoid unnecessary repetition.

Moreover, any combination of the various embodiments of the invention can be made without departing from the spirit of the invention, which should also be considered as disclosed herein.

Claims (10)

1. A feedback current control device, wherein the feedback current control device is disposed in a charger, the feedback current control device comprising:

the first switch module is positioned on a power supply circuit from the battery to the driver;

a second switch module;

a capacitor configured by the charger for charging the battery, the capacitor and the second switch module being located on a first current capture circuit; and

the control module is configured for the charger and used for controlling the battery to be charged and is used for executing the following operations:

receiving a feedback current characterization parameter, a charging parameter of the capacitor and a state parameter of the battery; and

and under the condition that the feedback current characterization parameter indicates that the feedback current exists on the power supply circuit, the charging parameter of the capacitor is smaller than a preset charging parameter, and the state parameter of the battery indicates that the lithium precipitation risk exists on the battery, the power supply circuit is conducted unidirectionally by controlling the first switch module so as to inhibit the feedback current from charging the battery, and the first current capturing circuit is conducted by controlling the second switch module so as to capture the feedback current by the capacitor.

2. The feedback current control device of claim 1, further comprising:

a third switch module; and

the energy dissipation device and the third switch module are positioned on the second current capturing circuit,

correspondingly, the control module is further configured to, when the feedback current characterization parameter indicates that there is a feedback current on the power supply circuit, the charging parameter of the capacitor is greater than or equal to the preset charging parameter, and the state parameter of the battery indicates that the battery has a lithium precipitation risk, control the first switch module to conduct the power supply circuit unidirectionally so as to prohibit the feedback current from charging the battery, and control the third switch module to conduct the second current capturing circuit so as to capture the feedback current by the energy consumer.

3. The feedback current control device of claim 2, wherein the energy consumer is a braking resistor, the braking resistor being connected to the housing of the charger by an insulating thermally conductive material.

4. The apparatus according to claim 2, wherein in the case where the first current capturing circuit is turned on by controlling the second switching module, the control module is further configured to determine that the capacitor has failed in the case where the charging parameter of the capacitor has not been continuously increased,

or in case the second current capturing circuit is turned on by controlling the third switching module, the control module is further configured to receive the temperature of the energy consumer and determine that the energy consumer is malfunctioning in case the temperature of the energy consumer is not continuously increasing.

5. The feedback current control device of claim 1, wherein the control module is further configured to, if the feedback current characterization parameter indicates that there is feedback current on the power supply circuit but the state parameter of the battery indicates that there is no risk of lithium precipitation for the battery, perform the following operations:

and controlling the first switch module to conduct the power supply circuit bidirectionally so as to charge the battery through the feedback current.

6. The feedback current control device of claim 1, wherein the control module is further configured to, if the state parameter of the battery indicates that there is no risk of lithium precipitation in the battery, perform the following operations:

the power supply circuit is turned on bidirectionally by controlling the first switching module, and the first current capturing circuit is turned on by the second switching module to charge the battery by the capacitor.

7. The feedback current control device of claim 1, wherein the feedback current characterization parameter indicates that there is feedback current on the power supply circuit comprises: the difference between the voltage at one end of the driver and the voltage at one end of the battery on the power supply circuit is larger than a preset voltage; or the current on the power supply circuit is larger than a preset current.

8. The feedback current control device of claim 1, wherein the state parameter of the battery indicates that the battery is at risk of lithium precipitation comprises: the temperature of the battery is less than or equal to a preset temperature; or the SOC of the battery is greater than or equal to a preset SOC.

9. A charger, the charger comprising: the feedback current control device according to any one of claims 1 to 8.

10. An aerial work vehicle, the aerial work vehicle comprising: the charger of claim 9.