A converter and control method thereof, and a controller

Abstract

The present invention provides a converter and a control method and a controller thereof, which relate to the field of battery detection technology. The converter comprises a first port, a second port, a main conversion unit and an auxiliary conversion unit. The first port is used to connect a first battery, the second port is used to connect a second battery, and the main conversion unit comprises a third port and a fourth port. The main conversion unit is used to convert the input voltage of the converter, and the auxiliary conversion unit is used to adjust the output voltage of the converter according to an impedance excitation signal, which can reduce the cost of impedance measurement.

Description

Technical Field

[0001] The present invention relates to the technical field of converters, and in particular to a converter and a control method and a controller thereof. Background Art

[0002] As the core of modern electronic devices, electric vehicles and energy storage stations, the performance and life of batteries directly affect the operating efficiency and cost of equipment. Battery impedance detection, as a key indicator of battery performance, can reflect the health status and remaining life of the battery, and is also closely related to its charging and discharging efficiency, temperature stability and safety. Therefore, accurate detection of battery impedance is of great significance for optimizing battery management systems, extending battery life and ensuring safe operation of equipment.

[0003] Several methods for measuring battery AC impedance have been proposed. These methods can be divided into two categories, namely offline impedance measurement and online impedance measurement. In the offline impedance measurement method, it is necessary to connect external specialized experimental equipment to the battery to obtain the AC impedance. This method is not suitable for use in actual online BMS. In the online impedance measurement method, an impedance measurement chip is generally used. The chip obtains the battery impedance by injecting an excitation signal and collecting voltage and current signals, but the chip cost is relatively high. The existing technology often uses a DC-DC converter to replace the chip for online AC impedance detection. However, for the application scenarios of multiple lithium batteries, multiple lithium batteries need to be equipped with a corresponding number of DC-DC converters. For example, for the power supply system of an on-board 800V lithium battery and a 12V lithium battery, each lithium battery power supply system needs to be equipped with a corresponding independent DC-DC converter, resulting in a high impedance detection cost. Summary of the invention

[0004] In view of this, one or more embodiments of the present specification provide a converter and a control method and a controller thereof.

[0005] To solve the above problems, one or more embodiments of this specification provide the following technical solutions:

[0006] In a first aspect, the present specification provides a converter, the converter comprising a first port, a second port, a main conversion unit and an auxiliary conversion unit, the first port being used to connect a first battery, the second port being used to connect a second battery, the main conversion unit comprising a third port and a fourth port; the main conversion unit being used to convert an input voltage of the converter, the auxiliary conversion unit being used to adjust an output voltage of the converter according to an impedance excitation signal;

[0007] When the first port is the input terminal of the converter and the second port is the output terminal of the converter, the third port is connected to the first port; the positive terminal of the fourth port is connected to the positive terminal of the second port, the negative terminal of the fourth port is connected to the first terminal of the output port of the auxiliary conversion unit, the second terminal of the output port is connected to the negative terminal of the second port, and the current signal and the voltage signal between the second ports are used to detect the impedance of the second battery;

[0008] When the second port is the input terminal of the converter and the first port is the output terminal of the converter, the positive terminal of the third port is connected to the positive terminal of the first port, the negative terminal of the third port is connected to the first terminal of the output port of the auxiliary conversion unit, and the negative terminal of the first port is connected to the second terminal of the output port; the fourth port is connected to the second port, and the current signal and the voltage signal between the first ports are used to detect the impedance of the first battery.

[0009] Optionally, the main conversion unit includes: a first converter, a second converter and a three-port transformer, and the three-port transformer includes a first transformation port, a second transformation port and a third transformation port;

[0010] The first voltage transformation port is connected to one port of the first converter, and the other port of the first converter is the third port;

[0011] The second voltage transformation port is connected to one port of the second converter, and the other port of the first converter is the fourth port;

[0012] The third voltage transformation port is connected to the input port of the auxiliary conversion unit.

[0013] Optionally, the auxiliary conversion unit includes a third converter and a rectifier:

[0014] One port of the rectifier is connected to one port of the third converter, another port of the rectifier is the input port, and another port of the third converter is the output port.

[0015] Optionally, the converter further comprises:

[0016] a first switch, a second switch, a third switch, a fourth switch, a fifth switch and a sixth switch;

[0017] The first switch is used to control the connection state between the negative terminal of the third port and the negative terminal of the first port;

[0018] The second switch is used to control the connection state between the first terminal of the output port and the negative terminal of the third port;

[0019] The third switch is used to control the connection state between the second terminal of the output port and the negative terminal of the first port;

[0020] The fourth switch is used to control the connection state between the negative terminal of the fourth port and the negative terminal of the second port;

[0021] The fifth switch is used to control the connection state between the first terminal of the output port and the negative terminal of the fourth port;

[0022] The sixth switch is used to control a connection state between the second terminal of the output port and the negative terminal of the fourth port.

[0023] In a second aspect, the present specification provides a converter control method, the converter control method is used to control the converter described in the first aspect, the converter control method comprising:

[0024] generating an impedance excitation signal;

[0025] generating a control signal according to the impedance excitation signal;

[0026] The auxiliary conversion unit in the converter is controlled according to the control signal, so as to control the auxiliary conversion unit to adjust the output voltage of the converter.

[0027] Optionally, generating a control signal according to the impedance excitation signal includes:

[0028] Acquire an output current signal of a main conversion unit in the converter, and determine a reverse fluctuation signal according to the output current signal;

[0029] The control signal is determined according to the reverse fluctuation signal and the impedance excitation signal.

[0030] Optionally, determining the reverse fluctuation signal according to the output current signal comprises:

[0031] Performing filtering on the output current signal to obtain a first current signal;

[0032] Performing AC component extraction processing on the first current signal to obtain an AC ripple component;

[0033] The AC ripple component is inverted to obtain the reverse ripple signal.

[0034] Optionally, determining the control signal according to the reverse fluctuation signal and the impedance excitation signal includes:

[0035] Acquire a first output voltage of a main conversion unit in the converter, wherein the first output voltage is a voltage of a third port or a fourth port of the converter;

[0036] determining a driving signal according to the first output voltage;

[0037] The control signal is determined according to the driving signal, the reverse fluctuation signal and the impedance excitation signal.

[0038] Optionally, determining a driving signal according to the first output voltage includes:

[0039] determining an output error voltage according to the first output voltage and a target voltage, wherein the target voltage is a preset voltage value;

[0040] Determining the duty cycle of each switch tube in the auxiliary conversion unit according to the output error voltage;

[0041] The driving signal is determined according to the duty cycle.

[0042] In a third aspect, the present specification provides a controller, which is used to control the converter described in the first aspect, and the controller includes a controller excitation signal generator and a control signal generator, wherein:

[0043] The excitation signal generator is used to generate an impedance excitation signal;

[0044] The control signal generator is used to generate a control signal according to the impedance excitation signal, and control the auxiliary conversion unit in the converter according to the control signal, so as to control the auxiliary conversion unit to adjust the output voltage of the converter.

[0045] Optionally, the controller further includes: a current loop, wherein:

[0046] The current loop is used to obtain an output current signal of a main conversion unit in the converter, and determine a reverse fluctuation signal according to the output current signal;

[0047] The control signal generator is further used to determine the control signal according to the reverse fluctuation signal and the impedance excitation signal.

[0048] Optionally, the controller further comprises: a voltage loop, wherein:

[0049] The voltage loop is used to obtain a first output voltage of a main conversion unit in the converter, and determine a driving signal according to the first output voltage, wherein the first output voltage is a voltage of a third port or a fourth port of the converter;

[0050] The control signal generator is further used to determine the control signal according to the drive signal, the reverse fluctuation signal and the impedance excitation signal.

[0051] The beneficial effects of a converter and its control method and controller provided by one or more embodiments of the present specification are as follows: the converter includes a main conversion unit and an auxiliary conversion unit, the main conversion unit converts the input voltage input to the converter, the auxiliary conversion unit can adjust the output voltage according to the impedance excitation signal so that the output voltage is within the required frequency, the output voltage of the converter acts on the battery connected to the output end of the converter, the battery will generate current and voltage responses according to its own electrochemical characteristics, and the voltage signal and current signal at both ends of the battery can be collected later to detect the impedance of the battery. The converter in the present invention is a bidirectional converter, that is, when one of the first port and the second end is used as the input end, the other port is used as the output end, and then the voltage can be converted to voltage. When the voltage conversion direction is different, the input end and the output end of the converter are different, and the connection method of the main conversion unit and the auxiliary conversion unit inside the converter is different. When the first port is the input end of the converter and the second port is the output end of the converter, the input voltage of the first port is introduced into the main conversion unit, and the main conversion unit The output of the converter is connected in series with the output of the auxiliary conversion unit. At this time, the output voltage of the converter acts on the second battery connected to the second port, and the second battery will generate a current response and a voltage response. The current signal and the voltage signal at both ends of the second battery are collected, that is, the current signal and the voltage signal between the second ports. The impedance of the second battery can be detected according to the current signal and the voltage signal between the second ports. On the contrary, when the second port is the input end of the converter and the first port is the output end of the converter, the input voltage of the second port is introduced into the main conversion unit, and the output of the main conversion unit is connected in series with the output of the auxiliary conversion unit. The main conversion unit and the auxiliary conversion unit are connected in series through different connection methods. At this time, the output voltage of the converter acts on the first battery connected to the first port, and the first battery will generate a current response and a voltage response. The current signal and the voltage signal at both ends of the first battery are collected, that is, the current signal and the voltage signal between the first ports. The impedance of the first battery can be detected according to the current signal and the voltage signal between the first ports. In the present invention, a converter is used, and impedance detection of the first battery and the second battery connected at both ends of the converter can be achieved by changing the voltage conversion direction and the connection method inside the converter.

[0052] The embodiments of the present invention can achieve the following beneficial effects: the converter in the present invention can realize bidirectional energy conversion between the first battery and the second battery, that is, the energy of the first battery is converted and transmitted to the second battery through the converter, or the energy of the second battery is converted and transmitted to the first battery through the converter; at the same time, during the energy conversion process between the first battery and the second battery, the impedance measurement of the battery can be completed, and the impedance measurement of the first battery and the second battery can be completed only by controlling one converter, thereby reducing the number of DC-DC converters equipped, thereby reducing the cost of impedance measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a structural schematic diagram of a converter when the first port is used as an input port according to an embodiment of the present invention;

[0054] Figure 2 is a schematic structural diagram of a converter according to an embodiment of the present invention when the second port is used as an input port;

[0055] Figure 3 It is a structural schematic diagram of another converter when the first port is used as the input port in an embodiment of the present invention;

[0056] Figure 4 It is a structural schematic diagram of another converter when the second port is used as the input port in an embodiment of the present invention;

[0057] Figure 5 A schematic diagram of the overall structure of a converter according to an embodiment of the present invention;

[0058] Figure 6 A circuit topology diagram of another converter according to an embodiment of the present invention;

[0059] Figure 7 A schematic diagram of a circuit when a converter according to an embodiment of the present invention is connected to a battery;

[0060] Figure 8 A circuit topology diagram of a converter when the first port is an input port according to an embodiment of the present invention;

[0061] Fig. 9 is a schematic diagram of a driving signal of a main conversion unit according to an embodiment of the present invention;

[0062] Fig.10 A circuit topology diagram of a converter when the second port is an input port according to an embodiment of the present invention;

[0063] Fig.11 A flowchart of a converter control method according to an embodiment of the present invention;

[0064] Fig.12A logic diagram of a control loop controlling an auxiliary conversion unit according to an embodiment of the present invention;

[0065] Fig.13 A logic diagram of an optional control loop of an embodiment of the present invention;

[0066] Fig.14 A logic diagram of another optional control loop of an embodiment of the present invention;

[0067] Fig.15 is a schematic diagram of a current signal finally output by a converter according to an embodiment of the present invention;

[0068] Fig.16 A schematic diagram of a converter controller according to an embodiment of the present invention;

[0069] Fig.17 A schematic diagram of another converter controller according to an embodiment of the present invention;

[0070] Fig.18 The figure is a schematic diagram of the structure of an electronic device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0071] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be interpreted as being limited to the embodiments described herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0072] It should be understood that the various steps described in the method embodiments of the present invention may be performed in different orders and / or in parallel. In addition, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this respect.

[0073] The term "including" and its variations used in this document are open inclusions, that is, "including but not limited to"; the term "based on" means "based at least in part on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first", "second", etc. mentioned in the present invention are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0074] It should be noted that the modifications of "one" and "plurality" mentioned in the present invention are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0075] The names of the messages or information exchanged between multiple devices in the embodiments of the present invention are only used for illustrative purposes, and are not used to limit the scope of these messages or information.

[0076] A converter provided by an embodiment of the present invention comprises a first port, a second port, a main conversion unit and an auxiliary conversion unit, wherein the first port is used to connect a first battery, the second port is used to connect a second battery, and the main conversion unit comprises a third port and a fourth port; the main conversion unit is used to convert an input voltage of the converter, and the auxiliary conversion unit is used to adjust the output voltage of the converter according to an impedance excitation signal;

[0077] Specifically, the converter is a bidirectional converter that can convert electric energy in two directions. The converter has two ports: a first port and a second port. The first port is used to connect to the first battery, and the second port is used to connect to the second battery. Both ports can be used as the input and output of the converter. When one of the ports is used as the input, the other port is used as the output, that is, when the first port is the input of the converter, the second port is the output of the converter. At this time, the voltage of the first battery is applied to the second battery through the converter conversion; conversely, when the second port is the input of the converter, the first port becomes the output of the converter. At this time, the voltage of the second battery is applied to the first battery through the converter conversion.

[0078] The converter includes two conversion units: a main conversion unit and an auxiliary conversion unit. The main conversion unit has two ports: a third port and a fourth port. Both ports can be used as the input and output of the main conversion unit. When one of the ports is used as the input, the other port is used as the output. The main conversion unit is responsible for converting the voltage input from the input of the converter to the converter, and outputting a voltage (a first output voltage) from the output of the main conversion unit. The impedance excitation signal controls the auxiliary conversion unit, and the auxiliary conversion unit adjusts the output voltage of the auxiliary conversion unit according to the impedance excitation signal, thereby adjusting the output voltage of the entire converter.

[0079] The auxiliary conversion unit adjusts the output voltage of the converter according to the impedance excitation signal, which acts on the battery connected to the output end of the converter, so that the battery generates corresponding current response and voltage response under the voltage excitation. The battery response to the excitation signal can be obtained by subsequently measuring the current signal and voltage signal of the battery. The impedance of the battery can be calculated using the measured voltage signal and current signal. For example, the impedance of the battery is calculated according to Ohm's law and the phase relationship. Collecting the current signal and voltage signal of the battery and calculating the impedance of the battery after injecting the impedance excitation signal belongs to the prior art and will not be repeated here.

[0080] like Figure 1 As shown, when the first port is the input terminal of the converter and the second port is the output terminal of the converter, the third port is connected to the first port; the positive terminal of the fourth port is connected to the positive terminal of the second port, the negative terminal of the fourth port is connected to the first terminal of the output port of the auxiliary conversion unit, and the second terminal of the output port is connected to the negative terminal of the second port;

[0081] Specifically, when the first port is the input end of the converter and the second port is the output end of the converter, the input end of the main voltage converter is the third port and the output end is the fourth port, the voltage flows from the first port to the second port, and the external input voltage is input to the converter from the first port;

[0082] The third port is connected to the first port, that is, the positive terminal of the first port is connected to the positive terminal of the third port, and the negative terminal of the first port is connected to the negative terminal of the third port, that is, the input voltage input to the first port is introduced into the main conversion unit through the third port, and the main conversion unit converts the input voltage;

[0083] The positive terminal of the second port is connected to the positive terminal of the fourth port, the negative terminal of the fourth port is connected to the first terminal of the output port of the auxiliary conversion unit, and the second terminal of the output port of the auxiliary conversion unit is connected to the negative terminal of the second port, so that the fourth port and the output port of the auxiliary conversion unit are connected in series, so that the voltage of the output port of the auxiliary conversion unit and the voltage of the fourth port are superimposed on the second port, that is, the voltage of the second port (the output voltage of the converter) is the sum of the voltage of the fourth port and the output port of the auxiliary conversion unit.

[0084] like Figure 2 As shown, when the second port is the input terminal of the converter and the first port is the output terminal of the converter, the positive terminal of the third port is connected to the positive terminal of the first port, the negative terminal of the third port is connected to the first terminal of the output port of the auxiliary conversion unit, and the negative terminal of the first port is connected to the second terminal of the output port; the fourth port is connected to the second port.

[0085] Specifically, when the second port is the input end of the converter and the first port is the output end of the converter, the input end of the main voltage converter is the fourth port and the output end is the third port, the voltage flows from the second port to the first port, and the external input voltage is input to the converter from the second port;

[0086] The fourth port is connected to the second port, that is, the positive terminal of the second port is connected to the positive terminal of the fourth port, and the negative terminal of the second port is connected to the negative terminal of the fourth port, that is, the input voltage input to the second port is introduced into the main conversion unit through the fourth port, and the main conversion unit converts the input voltage;

[0087] The positive terminal of the first port is connected to the positive terminal of the third port, the negative terminal of the third port is connected to the first terminal of the output port of the auxiliary conversion unit, and the second terminal of the output port of the auxiliary conversion unit is connected to the negative terminal of the first port, so that the third port and the output port of the auxiliary conversion unit are connected in series, so that the voltage of the output port of the auxiliary conversion unit and the voltage of the third port are superimposed on the first port, that is, the voltage of the first port (the output voltage of the converter) is the sum of the voltage of the third port and the output port of the auxiliary conversion unit.

[0088] In this embodiment, the converter includes a main conversion unit and an auxiliary conversion unit. The main conversion unit converts the input voltage input to the converter. The auxiliary conversion unit can adjust the output voltage according to the impedance excitation signal so that the output voltage is within the required frequency. The output voltage of the converter acts on the battery connected to the output end of the converter. The battery will generate current and voltage responses according to its own electrochemical characteristics. The voltage signal and current signal at both ends of the battery can be collected to detect the impedance of the battery. The converter in the present invention is a bidirectional converter, that is, when one of the first port and the second end is used as the input end, the other port is used as the output end, and then the voltage can be converted. When the voltage conversion direction is different, the input end and the output end of the converter are different. The connection method of the main conversion unit and the auxiliary conversion unit inside the converter is different. When the first port is the input end of the converter and the second port is the output end of the converter, the input voltage of the first port is introduced into the main conversion unit, and the output of the main conversion unit is connected in series with the output of the auxiliary conversion unit. At this time, the output voltage of the converter acts on the second battery connected to the second port, and the second battery will generate a current response and a voltage response. The current signal and the voltage signal at both ends of the second battery, that is, the current signal and the voltage signal between the second ports, are collected, and the impedance of the second battery can be detected according to the current signal and the voltage signal between the second ports. On the contrary, when the second port is the input end of the converter and the first port is the output end of the converter, the input voltage of the second port is introduced into the main conversion unit, and the output of the main conversion unit is connected in series with the output of the auxiliary conversion unit. The main conversion unit and the auxiliary conversion unit are connected in series through different connection methods. At this time, the output voltage of the converter acts on the first battery connected to the first port, and the first battery will generate a current response and a voltage response. The current signal and the voltage signal at both ends of the first battery, that is, the current signal and the voltage signal between the first ports, are collected, and the impedance of the first battery can be detected according to the current signal and the voltage signal between the first ports. The converter in the present invention can realize bidirectional energy conversion between the first battery and the second battery, that is, the energy of the first battery is converted and transmitted to the second battery through the converter, or the energy of the second battery is converted and transmitted to the first battery through the converter; at the same time, during the energy conversion process between the first battery and the second battery, the impedance measurement of the battery can be completed. The impedance measurement of the first battery and the second battery can be completed only by controlling one converter in this embodiment, which reduces the number of DC-DC converters and further reduces the cost of impedance measurement.

[0089] The converter in this embodiment can change the direction of energy flow. By controlling a converter in this embodiment, the impedance of the second battery can be detected when the energy of the first battery flows into the second battery, and the impedance of the first battery can be detected when the energy of the second battery flows into the first battery. The impedance detection of the two batteries can be achieved by simply controlling the converter.

[0090] Optionally, due to the connection method between the auxiliary conversion unit and the main conversion unit, the voltage of the output port of the auxiliary conversion unit and the output voltage of the main conversion unit are superimposed on the first port or the second port, that is, the output voltage of the converter is the sum of the voltage of the third port and the output port of the auxiliary conversion unit. In addition to adjusting the output voltage of the converter according to the impedance excitation signal to excite the battery at the output end, the auxiliary conversion unit can also adjust the output voltage of the auxiliary conversion unit in combination with the output voltage (first output voltage) of the main conversion unit to feedback and stabilize the output voltage of the auxiliary conversion unit at around the target voltage.

[0091] Optionally, the main conversion unit includes: a first converter, a second converter and a three-port transformer, and the three-port transformer includes a first transformation port, a second transformation port and a third transformation port;

[0092] The first voltage transformation port is connected to one port of the first converter, and the other port of the first converter is the third port;

[0093] The second voltage transformation port is connected to one port of the second converter, and the other port of the first converter is the fourth port;

[0094] The third voltage transformation port is connected to the input port of the auxiliary conversion unit.

[0095] Specifically, Figure 3 and Figure 4 As shown, the main conversion unit includes a first converter, a second converter and a three-port transformer. The first converter and the second converter are mainly used for voltage step-up or step-down and DC to AC conversion.

[0096] The three-port transformer is an inductive device with three ports, which is used to distribute the input voltage. The three-port transformer has three transformer ports, namely the first transformer port (corresponding to Figure 3 port Np in the second transformer port (corresponding to Figure 3 port Ns in the Figure 3 Naux), designate one port as the input port and the other two ports as output ports.

[0097] The first converter and the second converter can be choppers, and the three-port transformer is connected between the first converter and the second converter. The first converter is connected to the three-port transformer through the first transformer port, and the second converter is connected to the three-port transformer through the second transformer port. The output voltage of one chopper is input to the three-port transformer and output to the other chopper through the three-port transformer. Taking the first port as the input end of the converter as an example, the input voltage of the first port is introduced into the first converter, and the first converter steps up or steps down the input and converts it into an AC voltage, which is input into the three-port transformer through the first transformer port. The three-port transformer distributes the input according to the turn ratio relationship between the first transformer port and the second transformer port and the third transformer port, and the voltage distributed by the second transformer port is input to the second converter; taking the second port as the input end of the converter as an example, the input voltage of the second port is introduced into the second converter, and the second converter steps up or steps down the input and converts it into an AC voltage, which is input into the three-port transformer through the second transformer port. The three-port transformer distributes the input voltage according to the turn ratio relationship between the second transformer port and the first transformer port and the second transformer port, and the voltage distributed by the first transformer port is input to the first converter.

[0098] In addition, since the third transformer port is connected to the input port of the auxiliary conversion unit, the voltage allocated to the third transformer port is input to the auxiliary conversion unit. By adjusting the modulation method of the auxiliary conversion unit according to the impedance excitation signal, the auxiliary conversion unit adjusts the voltage input to the auxiliary conversion unit into an output voltage with the same frequency as the impedance excitation signal, superimposes it with the output voltage of the main auxiliary conversion unit, and acts on the first battery or the second battery through the first port or the second port.

[0099] In this embodiment, the connection between the first converter, the three-port transformer and the second converter realizes the conversion of the input voltage by the main voltage converter. The output of the main voltage converter is the output of the first converter or the second converter. The three-port transformer is used and the third port transformer is connected to the input end of the auxiliary conversion unit. The input voltage of the auxiliary conversion unit is actually derived from the input voltage of the first port or the second port, so that the main conversion unit and the auxiliary conversion unit actually share an input end, and no additional power supply is required to provide voltage for the auxiliary conversion unit, which further reduces the detection cost.

[0100] Exemplarily, the first converter and the second converter can adopt a full-bridge or half-bridge structure, which is composed of a switch tube, a capacitor and an inductor. The three windings of the three-port transformer are in a turn ratio relationship with each other, for example, M:N:1, where M and N are integers greater than or equal to 1. In different working modes, the transformer can effectively transfer energy and regulate voltage. The first converter and the second converter adopt different duty cycle controls in different working modes, but in a fixed working mode, the duty cycle remains unchanged, that is, a fixed duty cycle is used to control the two choppers to achieve efficient energy transmission. The auxiliary conversion unit further adjusts the output voltage according to the first output voltage to adjust the duty cycle to ensure the stability of the output voltage.

[0101] It should be noted that the first port and the second port of the converter are both DC voltages. The first converter and the second converter in the above embodiment use the same circuit structure, specifically, a half-bridge or full-bridge structure, and the components include switch tubes, capacitors and inductors.

[0102] Optionally, the auxiliary conversion unit includes a third converter and a rectifier:

[0103] One port of the rectifier is connected to one port of the third converter, another port of the rectifier is the input port, and another port of the third converter is the output port.

[0104] Specifically, Figure 3 and Figure 4 As shown, the auxiliary conversion unit is composed of a third converter and a rectifier. One port of the rectifier serves as the input port of the auxiliary conversion unit and can be connected to the third transformer port of the three-port transformer. Another port of the rectifier is connected to one port of the third converter. Another port of the third converter serves as the output port of the auxiliary conversion unit. The voltage output by the third transformer port is an AC voltage. The rectifier rectifies the AC voltage into a DC voltage and inputs the rectified DC voltage into the third converter. The third converter is a PWM (Pulse Width Modulation) converter. The PWM converter adjusts the conduction state of each switch in the PWM converter according to the impedance excitation signal to adjust the output voltage. The rectifier can be a half-wave rectifier, a full-wave rectifier or a bridge rectifier.

[0105] It should be noted that the structure of the rectifier is half-wave rectification or full-wave rectification, and the component structure includes a diode or a switch tube.

[0106] The third converter may be a pulse width modulation converter (PWM converter), which uses pulse width modulation (PWM) technology to control the on-time of each switch tube in the third converter, thereby generating an impedance excitation signal. The PWM converter may be a BUCK converter, a BOOST converter, or a BUCK-BOOST converter.

[0107] Optionally, the converter further includes: a first switch, a second switch, a third switch, a fourth switch, a fifth switch and a sixth switch;

[0108] The first switch is used to control the connection state between the negative terminal of the third port and the negative terminal of the first port;

[0109] The second switch is used to control the connection state between the first terminal of the output port and the negative terminal of the third port;

[0110] The third switch is used to control the connection state between the second terminal of the output port and the negative terminal of the first port;

[0111] The fourth switch is used to control the connection state between the negative terminal of the fourth port and the negative terminal of the second port;

[0112] The fifth switch is used to control the connection state between the first terminal of the output port and the negative terminal of the fourth port;

[0113] The sixth switch is used to control a connection state between the second terminal of the output port and the negative terminal of the fourth port.

[0114] Specifically, in addition to the main conversion unit and the auxiliary conversion unit, the converter is also provided with an additional switch. The connection mode of the main conversion unit and the auxiliary conversion unit is changed by changing the state of the additional switch, thereby adapting to different conversion modes of the converter.

[0115] Preferably, if Figure 5 As shown, there are six additional switches, namely the first switch, the second switch, the third switch, the fourth switch, the fifth switch and the sixth switch. The connection mode between the main conversion unit and the auxiliary conversion unit is changed by changing the switch state to ensure that the converter can flexibly realize bidirectional energy conversion.

[0116] The first switch is connected between the negative terminal of the third port and the negative terminal of the first port, and the first switch controls the negative terminal of the third port (corresponding to Figure 5 point a) and the negative terminal of the first port (corresponding to Figure 5When the first switch is disconnected, the negative terminal of the third port is not directly connected to the negative terminal of the first port. When the first switch is disconnected, the negative terminal of the third port is directly connected to the negative terminal of the first port, and the voltage of the first port is equal to the voltage of the third port.

[0117] The second switch is connected between the first terminal of the auxiliary conversion unit output port and the negative terminal of the third port. The second switch controls the first terminal of the auxiliary conversion unit output port (corresponding to point c in 5) and the negative terminal of the third port (corresponding to point c in 5). Figure 5 The connection state of point a in the figure is as follows: when the second switch is opened, the first terminal of the output port of the auxiliary conversion unit and the negative terminal of the third port are not directly connected; when the second switch is closed, the first terminal of the output port of the auxiliary conversion unit and the negative terminal of the third port are directly connected.

[0118] The third switch is connected between the second terminal of the auxiliary conversion unit output port and the negative terminal of the first port, and the third switch controls the second terminal of the auxiliary conversion unit output port (corresponding to Figure 5 point d in the figure) and the negative terminal of the first port (corresponding to Figure 5 The connection state of the auxiliary conversion unit output port is point b), that is, when the third switch is disconnected, the second terminal of the auxiliary conversion unit output port is not directly connected to the negative terminal of the first port, and when the third switch is closed, the second terminal of the auxiliary conversion unit output port is directly connected to the negative terminal of the first port.

[0119] The fourth switch is connected between the negative terminal of the fourth port and the negative terminal of the second port, and the fourth switch controls the negative terminal of the fourth port (corresponding to Figure 5 g point) and the negative terminal of the second port (corresponding to Figure 5 h point in the middle), that is, when the fourth switch is opened, the negative terminal of the fourth port is not directly connected to the negative terminal of the second port, and when the fourth switch is closed, the negative terminal of the fourth port is directly connected to the negative terminal of the second port, and the voltage of the second port is equal to the voltage of the fourth port.

[0120] The fifth switch is connected between the first terminal of the auxiliary conversion unit output port and the negative terminal of the fourth port, and the fifth switch controls the first terminal of the auxiliary conversion unit output port (corresponding to point e in 5) and the negative terminal of the fourth port (corresponding to point Figure 5 The connection state of the auxiliary conversion unit output port (point g) is shown in FIG. 1 , that is, when the fifth switch is disconnected, the first terminal of the auxiliary conversion unit output port and the negative terminal of the fourth port are not directly connected; when the fifth switch is closed, the first terminal of the auxiliary conversion unit output port and the negative terminal of the fourth port are directly connected.

[0121] The sixth switch is connected between the second terminal of the auxiliary conversion unit output port and the negative terminal of the second port, and the sixth switch controls the second terminal of the auxiliary conversion unit output port (corresponding to Figure 5 point f in the figure) and the negative terminal of the second port (corresponding to Figure 5 h point in the figure), that is, when the sixth switch is disconnected, the second terminal of the auxiliary conversion unit output port and the negative terminal of the second port are not directly connected, and when the sixth switch is closed, the second terminal of the auxiliary conversion unit output port and the negative terminal of the second port are directly connected.

[0122] It should be noted that Figure 5 Point d and point f in can be the same point. Figure 5 The c and e in the figure may be the same point. Here, for the convenience of viewing, the output port of the auxiliary conversion unit is divided into two left and right ports, which may actually refer to the same output port.

[0123] Based on the above six switches, when the voltage is converted from the first port to the second port, that is, the first port is the input end of the converter and the second port is the output end of the converter, the first switch, the fifth switch and the sixth switch are disconnected, and the second switch, the third switch and the fourth switch are closed. At this time, the connection status of each unit of the converter is as follows: Figure 3 As shown, the input voltage input to the first port is introduced into the main conversion unit through the third port, and the fourth port is connected in series with the output port of the auxiliary conversion unit, so that the voltage of the output port of the auxiliary conversion unit and the voltage of the fourth port are superimposed on the second port.

[0124] When the voltage is converted from the second port to the first port, that is, the second port is the input end of the converter and the first port is the output end of the converter, the second switch, the third switch and the fourth switch are disconnected, and the first switch, the fifth switch and the sixth switch are closed. At this time, the connection status of each unit of the converter is as follows: Figure 4 As shown, the input voltage input to the second port is introduced into the main conversion unit through the fourth port, and the third port is connected in series with the output port of the auxiliary conversion unit, so that the voltage of the output port of the auxiliary conversion unit and the voltage of the third port are superimposed on the first port.

[0125] Taking the first converter and the second converter using full-bridge structure, the rectifier using diode full-wave rectifier circuit, and the third converter using synchronous buck circuit as an example, the overall topology of the converter is as follows: Figure 6As shown, the first converter includes a switch tube Q1, a switch tube Q2, a switch tube Q3 and a switch tube Q4; the three-port transformer includes a first transformation port Np, a second transformation port Ns and a third transformation port Naux; the second converter includes a switch tube Q5, a switch tube Q6, a switch tube Q7 and a switch tube Q8; the rectifier includes a diode D1, a diode D2, a diode D3 and a diode D4, and the third converter is composed of a switch tube Q9, a switch tube Q10, an inductor Ldc, a capacitor C3 and a capacitor C4.

[0126] The switch tubes Q1 and Q3 constitute the first bridge arm of the full-bridge structure of the first converter, the switch tubes Q2 and Q4 constitute the second bridge arm of the full-bridge structure of the first converter, one end of the first transformer port Np of the three-port transformer is connected to the point VB1 in the second bridge arm, and the other end of the first transformer port Np of the three-port transformer is connected to the point VB2 in the first bridge arm; the switch tubes Q5 and Q7 constitute the first bridge arm of the full-bridge structure of the second converter, the switch tubes Q6 and Q8 constitute the second bridge arm of the full-bridge structure of the second converter, one end of the second transformer port Ns of the three-port transformer is connected to the point VB3 of the first bridge arm of the second converter, and the other end of the second transformer port Ns of the three-port transformer is connected to the point VB4 of the second bridge arm of the second converter, the circuit structure of the main conversion unit composed of the first converter, the second converter and the three-port transformer is symmetrical, and can realize bidirectional energy flow, and the capacitors C1 and C2 are respectively used for voltage stabilization and filtering of the battery or input power supply.

[0127] Diode D1 and diode D2 constitute the first bridge arm of the rectifier, and point VB5 of the first bridge arm is connected to one end of the third transformer port Naux of the three-port transformer. Diode D3 and diode D4 constitute the second bridge arm of the rectifier, and point VB6 of the second bridge arm is connected to the other end of the third transformer port Naux of the three-port transformer. The output of the rectifier circuit is connected to the third converter.

[0128] Taking the energy exchange between the high-voltage battery pack (corresponding to the first battery) and the low-voltage battery pack (corresponding to the second battery) in the electric vehicle as an example, further explanation is given, such as Figure 7 The first port is connected to a high-voltage power battery pack, and the second port is connected to a low-voltage power battery pack.

[0129] When the high-voltage power battery pack of the electric vehicle charges the low-voltage battery pack, that is, the first port is the input port and the second port is the output port, Figure 7 The first switch, the fifth switch and the sixth switch are closed, and the second switch, the third switch and the fourth switch are opened. At this time, the connection relationship between the converter and the battery pack is as follows: Figure 8As shown: the positive terminal of the high-voltage power battery pack is connected to one end of the capacitor C1 and the drain of the switch tube Q1 in the full-bridge circuit of the first converter, and the negative terminal of the high-voltage power battery pack is connected to the other end of the capacitor and the source of the switch tube Q3 in the first converter, that is, the positive terminal of the third port is connected to the positive terminal of the first port, and the negative terminal of the third port is connected to the negative terminal of the first port; the positive terminal of the low-voltage battery pack is connected to one end of the capacitor C2 and the drain of the switch tube Q6 in the full-bridge circuit of the second converter, the negative terminal of the low-voltage battery pack is connected to the other end of the capacitor C2 and the output terminal AUX- of the third converter, and the source of the switch tube Q8 in the full-bridge circuit of the second converter is connected to the PWM converter output terminal AUX+, that is, the positive terminal of the fourth port is connected to the positive terminal of the second port, the negative terminal of the fourth port is connected to the first terminal of the output port of the auxiliary conversion unit, and the second terminal of the output port is connected to the negative terminal of the second port. For example, the standard rated voltage of the high-voltage power battery pack Vbat1 is 400V, and the standard rated voltage of the low-voltage battery pack Vbat2 is 12V. At this time, the target voltage is 12V, I2 is the output current signal, V2 is the output voltage value of the main voltage conversion unit, that is, the first output voltage, and Vaux is the output voltage value of the auxiliary voltage conversion unit, that is, the second output voltage. In this working state, Vbat2=V2+Vaux.

[0130] The main conversion unit adopts fixed duty cycle control, such as Fig. 9 As shown, the switch tubes Q1, Q4, Q6, and Q7 use the same driving signal, the switch tubes Q2, Q3, Q5, and Q8 use the same driving signal, and the driving signals of the switch tubes Q1 and Q3, the switch tubes Q2 and Q4, the switch tubes Q5 and Q7, and the switch tubes Q6 and Q8 are complementary.

[0131] When the low-voltage power battery pack of the electric vehicle charges the high-voltage battery pack, that is, the second port is the input port and the first port is the output port, Figure 7 The second switch, the third switch and the fourth switch are closed, and the first switch, the fifth switch and the sixth switch are opened. At this time, the connection relationship between the converter and the battery pack is as follows: Fig.10As shown: the positive terminal of the low-voltage battery pack is connected to one end of the capacitor C2 and the drain of the switch tube Q6 in the full-bridge circuit of the second converter, and the negative terminal of the low-voltage battery pack is connected to the other end of the capacitor and the source of the switch tube Q8 in the full-bridge circuit of the second converter, that is, the positive terminal of the fourth port is connected to the positive terminal of the second port, and the negative terminal of the fourth port is connected to the negative terminal of the second port; the positive terminal of the high-voltage power battery pack is connected to one end of the capacitor C1 and the drain of the switch tube Q1 in the full-bridge circuit of the first converter, the negative terminal of the high-voltage power battery pack is connected to the other end of the capacitor C1 and the output terminal AUX- of the third converter, and the source of the switch tube Q3 in the full-bridge circuit of the first converter is connected to the positive terminal of the second port. The output terminal AUX+ of the three converters is connected, that is, the positive terminal of the third port is connected to the positive terminal of the first port, the negative terminal of the third port is connected to the first terminal of the output port of the auxiliary conversion unit, and the negative terminal of the first port is connected to the second terminal of the output port; wherein, the standard rated voltage of the high-voltage power battery pack Vbat1 is 400V, the standard rated voltage of the low-voltage battery pack Vbat2 is 12V, I1 is the output current signal, and the target voltage is 400V at this time, V1 is the output voltage value of the main conversion unit, that is, the first output voltage, and Vaux is the output voltage value of the auxiliary conversion unit, that is, the second output voltage. In this working state, Vbat1=V1+Vaux.

[0132] like Fig.11 As shown, the present invention provides a converter control method, the converter control method is used to control the converter in the above embodiment, and the converter control method includes:

[0133] Step S100, generating an impedance excitation signal;

[0134] Specifically, the impedance excitation signal may be a sine wave, square wave or other form of signal with a specific frequency and amplitude, which will be used to excite the battery, thereby inducing its current response, so as to subsequently measure the impedance of the battery.

[0135] Step S200, generating a control signal according to the impedance excitation signal;

[0136] Step S300: controlling an auxiliary conversion unit in a converter according to the control signal, so as to control the auxiliary conversion unit to adjust the output voltage of the converter.

[0137] Specifically, a corresponding control signal is generated according to the impedance excitation signal, and the control signal is used to control the duty cycle of each switch tube in the auxiliary conversion unit in the converter, so as to adjust the output voltage of the auxiliary conversion unit and apply external excitation to the battery at the output end of the converter, so that the impedance characteristics inside the battery can be expressed through changes in voltage and current.

[0138] In this embodiment, an impedance excitation signal is generated, and a control signal is generated based on the signal. Finally, the output voltage is adjusted by controlling the auxiliary conversion unit in the converter, thereby realizing external excitation of the battery impedance. Subsequently, the current signal and voltage signal of the battery can be collected to realize accurate measurement of the battery impedance.

[0139] Optionally, generating a control signal according to the impedance excitation signal includes: acquiring an output current signal of a main conversion unit in the converter, and determining a reverse fluctuation signal according to the output current signal; and determining the control signal according to the reverse fluctuation signal and the impedance excitation signal.

[0140] Specifically, a ripple signal is generated in the main voltage conversion unit during the voltage conversion process and also acts on the battery at the output end. The ripple signal is superimposed in the battery with the excitation given to the battery by the output voltage of the auxiliary conversion unit, resulting in a deviation in the excitation frequency, which will reduce the impedance detection accuracy. Therefore, in this embodiment, the output current signal of the main voltage conversion unit is sampled, that is, the output current signal in the converter is obtained, and the reverse fluctuation signal corresponding to the output current signal is determined. The control signal is determined in combination with the impedance excitation signal and the reverse fluctuation signal, and the output voltage of the auxiliary conversion unit is adjusted according to the control signal determined in this case.

[0141] The deviation caused by the ripple signal of the main conversion unit is eliminated by the output voltage adjusted accordingly by the reverse fluctuation signal, that is, the signal that finally reaches the low voltage only contains the fluctuation caused by the impedance excitation signal, thereby improving the battery impedance detection accuracy.

[0142] Optionally, determining the reverse fluctuation signal based on the output current signal includes: filtering the output current signal to obtain a first current signal; extracting an AC component of the first current signal to obtain an AC ripple component; and inverting the AC ripple component to obtain the reverse fluctuation signal.

[0143] Specifically, the output current signal is first filtered to remove high-frequency noise and unnecessary interference to accurately extract the AC ripple component of the output current signal, the AC ripple component is extracted from the first current signal, the periodic component in the signal is retained to obtain the change of the current under periodic fluctuations, and the extracted AC ripple component is inverted, that is, the signal of the AC ripple component is negatively valued to obtain a reverse fluctuation signal, and the reverse fluctuation signal and the AC ripple component can offset each other.

[0144] Optionally, determining the control signal according to the reverse fluctuation signal and the impedance excitation signal includes: obtaining a first output voltage of a main conversion unit in the converter, wherein the first output voltage is a voltage of a third port or a fourth port of the converter; determining a drive signal according to the first output voltage; and determining the control signal according to the drive signal, the reverse fluctuation signal and the impedance excitation signal.

[0145] Optionally, determining the driving signal based on the first output voltage includes: determining an output error voltage based on the first output voltage and a target voltage, wherein the target voltage is a preset voltage value; determining a duty cycle of each switching tube in the auxiliary conversion unit based on the output error voltage; and determining the driving signal based on the duty cycle.

[0146] Specifically, the first output voltage is the voltage output by the main conversion unit in the converter. When the first port is the input end of the converter and the second port is the output end of the converter, the first output voltage is the voltage of the fourth port (corresponding to Figure 8 V2 in the figure), when the second port is the input terminal of the converter and the first port is the output terminal of the converter, the first output voltage is the voltage of the third port (corresponding to Fig.10 in V1).

[0147] The target voltage is a voltage value preset according to the requirement. The obtained first output voltage is compared with the preset target voltage to calculate the output error voltage, and the error voltage is supplemented by the auxiliary conversion unit.

[0148] When the first port is an output terminal, the target voltage is Vset1, and when the second port is an output terminal, the target voltage is Vset2.

[0149] According to the calculated output error voltage, the corresponding driving signal of the auxiliary conversion unit is determined. The driving signal is used to control the conduction time of the switch tube in the auxiliary conversion unit, so that the voltage output by the auxiliary conversion unit (the second output voltage) is the same as the error voltage, and then the output voltage of the entire converter is the sum of the first output voltage and the second output voltage. The auxiliary conversion unit provides voltage compensation for the main conversion unit, so that the output voltage of the converter is stable at the target voltage.

[0150] It should be noted that a fixed duty cycle control is adopted for the main voltage conversion unit. When the input voltage of the converter and the connected battery are replaced, the duty cycle of the main voltage conversion unit cannot be adjusted through voltage feedback, which causes fluctuations in the output voltage of the converter. In this case, an auxiliary conversion unit with adjustable duty cycle is required to compensate for the error voltage caused by the replacement of the input voltage of the converter and the connected battery.

[0151] In this embodiment, the output error voltage is determined by obtaining the first output voltage of the main conversion unit in the converter and comparing it with the preset target voltage, so that the deviation between the output voltage of the main conversion unit and the target voltage can be monitored in real time. The driving signal generated by the output error voltage can effectively control the working state of the auxiliary conversion unit, and then adjust the output voltage of the auxiliary conversion unit. By controlling the output of the auxiliary conversion unit, the output voltage of the entire converter can be accurately controlled, so that the output voltage of the converter is stabilized at the target voltage.

[0152] According to the output error voltage, the duty cycle of each switch tube in the auxiliary conversion unit is calculated, which reflects the proportion of time the switch tube is turned on in one cycle. According to the control strategy, the duty cycle of each switch tube can be dynamically adjusted according to the size and change rate of the error voltage. After calculating the duty cycle, a drive signal is generated. The generation of the drive signal usually requires converting the duty cycle into a form suitable for PWM signal control. The duty cycle is mapped to the corresponding PWM waveform. The larger the duty cycle, the longer the high level time of the corresponding PWM signal. After obtaining the drive signal, the voltage output of the auxiliary voltage conversion unit is superimposed with the reverse fluctuation signal and the impedance excitation signal to obtain the control signal.

[0153] For example, if Fig.12 As shown, taking the turns ratio of 33:1 of the third-port transformer Np end (the first transformer port) and the three-port transformer Ns end as an example, when the input voltage Vbat1=400V, without connecting the battery, the output voltage value V2 of the main voltage conversion unit is 12V; when the input voltage Vbat2=12V, without connecting the battery, the output voltage value V1 of the main voltage conversion unit is 400V. However, in practice, the output end of the main power channel will be connected to the battery. For example, when the high-voltage battery pack charges the low-voltage battery pack, the charging current will change with the charging time. If only the main conversion unit is used to charge the battery, since the main conversion unit adopts a fixed duty cycle control, the output voltage will not be adjusted. Therefore, in this embodiment, the output voltage is adjusted in combination with the auxiliary conversion unit. Fig.12 A control signal is generated through a control loop, and a driving signal acts on the third converter. Specifically, a voltage loop collects a voltage signal (a first output voltage) of a main conversion unit through a differential sampling circuit, compares it with a voltage given value (a target voltage), and obtains a driving signal by performing signal processing according to an error value; a current loop collects an output current signal, and the output current signal is filtered through a band-stop filter, and an AC component (AC ripple component) in the filtered signal is extracted, and the AC component is reversed to obtain a reverse fluctuation signal, and an impedance excitation signal with a fixed frequency or a variable frequency is generated through an excitation signal generator. After the driving signal, the reverse fluctuation signal, and the impedance excitation signal are superimposed, the superimposed signal is input into a PWM signal generator to generate a control signal.

[0154] Optionally, Fig.13 A control loop is also provided, and the third converter in the auxiliary conversion unit is controlled when the high-voltage battery pack charges the low-voltage battery pack. At this time, the third converter in the auxiliary conversion unit collects the output voltage V2 (corresponding to the first output voltage) of the main conversion unit, and after passing through the signal processing circuit, it is subtracted from the output setting value Vbat2_ref value (corresponding to the target voltage) to obtain a feedback value Vaux_ref (corresponding to the error voltage), and the feedback value Vaux_ref is used as a given value output by the third converter, that is, the feedback value Vaux_ref determines the output voltage value Vaux of the third converter. In the control loop, the difference between the feedback value Vaux_ref and the output voltage Vaux of the third converter is processed by the first control unit to obtain an error value. The third converter also has the function of generating voltage fluctuations by superimposing an impedance excitation signal with a fixed or variable frequency through an excitation signal generator, wherein the impedance excitation signal is an AC signal, and the impedance excitation signal is ,in , is the impedance excitation signal frequency, for example, a fixed frequency , by applying the impedance excitation signal Added to the first control unit output error value , so that the duty cycle pulse signal will also change with the impedance excitation signal frequency Fluctuations, and finally the third converter output voltage Vaux is superimposed with a frequency of The fluctuation acts on the low-voltage battery pack, and the battery impedance value can be obtained by collecting the voltage AC component and current AC component in the low-voltage battery pack.

[0155] In addition, since the main voltage converter will generate output ripple, it will also act on the low-voltage battery pack, affecting the impedance measurement accuracy. Therefore, the control loop will collect the output current of the main voltage converter (corresponding to Fig.12 I2 in the figure), passes through a band-stop filter to filter out the frequency of the impedance excitation signal The AC component extraction unit extracts the AC component in the unfiltered signal (corresponding to the first current signal), and the reverse unit reverses the AC component to obtain a reverse ripple AC signal. (corresponding to the reverse fluctuation signal), by and reverse ripple AC signal Added to the first control unit output error value ,get , the error The duty cycle signal of the third converter (corresponding to Fig.13 The pulse in the third converter is the control signal), which is controlled by the PWM signal distribution unit to control the switch tube Q9 and the switch tube Q10. The drive pulses of the switch tube Q9 and the switch tube Q10 are complementary. Finally, the output voltage of the third converter is , and the voltage reaching the low-voltage battery pack only includes the fluctuation caused by the impedance excitation signal. In this embodiment, in the control loop of the auxiliary voltage conversion unit, the output voltage Vaux of the third converter is affected by the reverse ripple signal and the impedance excitation signal. Since the output end of the main conversion unit is connected in series with the output end of the third converter, the voltage fluctuation of the reverse fluctuation signal in the output voltage of the main conversion unit and the third converter cancel each other out, so as to eliminate the voltage fluctuation caused by the output current ripple of the main conversion unit to the voltage reaching the low-voltage battery pack, thereby improving the impedance detection accuracy.

[0156] Optionally, Fig.14 A control circuit is also provided to control the third converter, and the third converter is controlled when the high-voltage battery pack charges the low-voltage battery pack and when the low-voltage battery pack charges the high-voltage battery pack. Fig.13 The charging scenario of the high-voltage power battery pack and the low-voltage battery pack shown is the same, only the feedback signal is different, which will not be repeated here.

[0157] The final output current signal of the converter is as follows: Fig.15 As shown, I_101 is the current signal output by the converter in this embodiment, and I_102 is the current signal output by the converter of the main conversion unit. It can be seen that when detecting impedance in this embodiment, the converter in this embodiment can provide a more stable impedance excitation for the battery.

[0158] like Fig.16 As shown, a controller provided by an embodiment of the present invention includes:

[0159] The controller excitation signal generator and the control signal generator, wherein,

[0160] The excitation signal generator is used to generate an impedance excitation signal;

[0161] The control signal generator is used to generate a control signal according to the impedance excitation signal, and control the auxiliary conversion unit in the converter according to the control signal, so as to control the auxiliary conversion unit to adjust the output voltage of the converter.

[0162] Alternatively, if Fig.17As shown, the controller also includes: a current loop, wherein the current loop is used to obtain the output current signal of the main conversion unit in the converter, and determine the reverse fluctuation signal based on the output current signal; the control signal generator is also used to determine the control signal based on the reverse fluctuation signal and the impedance excitation signal.

[0163] Alternatively, if Fig.17 As shown, the controller also includes: a voltage loop, wherein the voltage loop is used to obtain the first output voltage of the main conversion unit in the converter, and determine the drive signal according to the first output voltage, wherein the first output voltage is the voltage of the third port or the fourth port of the converter; the control signal generator is also used to determine the control signal according to the drive signal, the reverse fluctuation signal and the impedance excitation signal.

[0164] Alternatively, if Fig.17 As shown, the current loop includes a band-stop filter, an AC component extractor, and an inverter, wherein the band-stop filter is used to filter the output current signal to obtain a first current signal; the AC component extractor is used to extract the AC component of the first current signal to obtain an AC ripple component; and the inverter is used to invert the AC ripple component to obtain the reverse fluctuation signal.

[0165] Alternatively, if Fig.17 As shown, the voltage loop includes a differential sampling circuit and a signal determiner, wherein the differential sampling circuit is used to obtain the first output voltage of the main conversion unit in the converter, and the signal determiner is used to determine the output error voltage according to the first output voltage and the target voltage, wherein the target voltage is a preset voltage value; the duty cycle of each switch tube in the auxiliary conversion unit is determined according to the output error voltage; and the drive signal is determined according to the duty cycle.

[0166] like Fig.18 As shown, an electronic device 1800 provided by an embodiment of the present invention includes a memory 1810 and a processor 1820; the memory 1810 is used to store a computer program; the processor 1820 is used to implement the converter control method as described above when executing the computer program.

[0167] In other words, an electronic device 1800 includes a memory 1810 and a processor 1820 coupled to the memory 1810; the memory 1810 is configured to store a computer program; and the processor 1820 is configured to perform the following operations when executing the computer program:

[0168] generating an impedance excitation signal;

[0169] generating a control signal according to the impedance excitation signal;

[0170] The auxiliary conversion unit in the converter is controlled according to the control signal, so as to control the auxiliary conversion unit to adjust the output voltage of the converter.

[0171] An embodiment of the present invention provides a computer-readable storage medium, wherein a computer program is stored on the storage medium. When the computer program is executed by a processor, the converter control method as described above is implemented.

[0172] In other words, a non-volatile computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the processor performs the following operations:

[0173] generating an impedance excitation signal;

[0174] generating a control signal according to the impedance excitation signal;

[0175] The auxiliary conversion unit in the converter is controlled according to the control signal, so as to control the auxiliary conversion unit to adjust the output voltage of the converter.

[0176] An electronic device 1800 that can be used as a server or client of the present invention will now be described, which is an example of a hardware device that can be applied to various aspects of the present invention. Electronic device 1800 is intended to represent various forms of digital electronic computer equipment, such as laptop computers, desktop computers, workbenches, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. Electronic device 1800 can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples, and are not intended to limit the implementation of the present invention described and / or required herein.

[0177] The electronic device 1800 includes a computing unit, which can perform various appropriate actions and processes according to a computer program stored in a read-only memory (ROM) or a computer program loaded from a storage unit into a random access memory (RAM). In the RAM, various programs and data required for the operation of the device can also be stored. The computing unit, ROM, and RAM are connected to each other via a bus. An input / output (I / O) interface is also connected to the bus.

[0178] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method can be implemented by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, the storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc. In the present application, the unit described as a separate component may or may not be physically separated, and the component displayed as a unit may or may not be a physical unit, that is, it may be located in one place, or it may be distributed on multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiment of the present invention. In addition, each functional unit in each embodiment of the present invention can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0179] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A converter, characterized in that: The converter comprises a first port, a second port, a main conversion unit and an auxiliary conversion unit, wherein the first port is used to connect a first battery, the second port is used to connect a second battery, and the main conversion unit comprises a third port and a fourth port; the main conversion unit is used to convert an input voltage of the converter, and the auxiliary conversion unit is used to adjust an output voltage of the converter according to an impedance excitation signal; When the first port is the input terminal of the converter and the second port is the output terminal of the converter, the third port is connected to the first port; the positive terminal of the fourth port is connected to the positive terminal of the second port, the negative terminal of the fourth port is connected to the first terminal of the output port of the auxiliary conversion unit, the second terminal of the output port is connected to the negative terminal of the second port, and the current signal and the voltage signal between the second ports are used to detect the impedance of the second battery; When the second port is the input terminal of the converter and the first port is the output terminal of the converter, the positive terminal of the third port is connected to the positive terminal of the first port, the negative terminal of the third port is connected to the first terminal of the output port of the auxiliary conversion unit, and the negative terminal of the first port is connected to the second terminal of the output port; the fourth port is connected to the second port, and the current signal and the voltage signal between the first ports are used to detect the impedance of the first battery.

2. The converter according to claim 1, characterized in that The main conversion unit includes: a first converter, a second converter and a three-port transformer, wherein the three-port transformer includes a first transformation port, a second transformation port and a third transformation port; The first voltage transformation port is connected to one port of the first converter, and the other port of the first converter is the third port; The second voltage transformation port is connected to one port of the second converter, and the other port of the second converter is the fourth port; The third voltage transformation port is connected to the input port of the auxiliary conversion unit.

3. The converter according to claim 2, characterized in that The auxiliary conversion unit includes a third converter and a rectifier: One port of the rectifier is connected to one port of the third converter, another port of the rectifier is the input port, and another port of the third converter is the output port.

4. The converter according to claim 1, characterized in that The converter further comprises: a first switch, a second switch, a third switch, a fourth switch, a fifth switch and a sixth switch; The first switch is used to control the connection state between the negative terminal of the third port and the negative terminal of the first port; The second switch is used to control the connection state between the first terminal of the output port and the negative terminal of the third port; The third switch is used to control the connection state between the second terminal of the output port and the negative terminal of the first port; The fourth switch is used to control the connection state between the negative terminal of the fourth port and the negative terminal of the second port; The fifth switch is used to control the connection state between the first terminal of the output port and the negative terminal of the fourth port; The sixth switch is used to control a connection state between the second terminal of the output port and the negative terminal of the second port.

5. A converter control method, characterized in that: The converter control method is used to control the converter according to any one of claims 1 to 4, and the converter control method comprises: generating an impedance excitation signal; generating a control signal according to the impedance excitation signal; The auxiliary conversion unit in the converter is controlled according to the control signal, so as to control the auxiliary conversion unit to adjust the output voltage of the converter.

6. The converter control method according to claim 5, characterized in that: The step of generating a control signal according to the impedance excitation signal comprises: Acquire an output current signal of a main conversion unit in the converter, and determine a reverse fluctuation signal according to the output current signal; The control signal is determined according to the reverse fluctuation signal and the impedance excitation signal.

7. The converter control method according to claim 6, characterized in that: Determining the reverse fluctuation signal according to the output current signal comprises: Performing filtering on the output current signal to obtain a first current signal; performing AC component extraction processing on the first current signal to obtain an AC ripple component; The AC ripple component is inverted to obtain the reverse ripple signal.

8. The converter control method according to claim 6, characterized in that: The determining the control signal according to the reverse fluctuation signal and the impedance excitation signal comprises: Acquire a first output voltage of a main conversion unit in the converter, wherein the first output voltage is a voltage of a third port or a fourth port of the converter; determining a driving signal according to the first output voltage; The control signal is determined according to the driving signal, the reverse fluctuation signal and the impedance excitation signal.

9. The converter control method according to claim 8, characterized in that: The step of determining a driving signal according to the first output voltage comprises: determining an output error voltage according to the first output voltage and a target voltage, wherein the target voltage is a preset voltage value; Determining the duty cycle of each switch tube in the auxiliary conversion unit according to the output error voltage; The driving signal is determined according to the duty cycle.

10. A controller, characterized in that: The controller is used to control the converter according to any one of claims 1 to 4, and the controller includes a controller excitation signal generator and a control signal generator, wherein: The excitation signal generator is used to generate an impedance excitation signal; The control signal generator is used to generate a control signal according to the impedance excitation signal, and control the auxiliary conversion unit in the converter according to the control signal, so as to control the auxiliary conversion unit to adjust the output voltage of the converter.

11. The controller according to claim 10, characterized in that: The controller further includes: a current loop, wherein: The current loop is used to obtain an output current signal of a main conversion unit in the converter, and determine a reverse fluctuation signal according to the output current signal; The control signal generator is further used to determine the control signal according to the reverse fluctuation signal and the impedance excitation signal.

12. The controller according to claim 11, characterized in that: The controller further comprises: a voltage loop, wherein: The voltage loop is used to obtain a first output voltage of a main conversion unit in the converter, and determine a driving signal according to the first output voltage, wherein the first output voltage is a voltage of a third port or a fourth port of the converter; The control signal generator is further used to determine the control signal according to the drive signal, the reverse fluctuation signal and the impedance excitation signal.

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