A backup power supply circuit for an electric drive controller

Abstract

The utility model relates to the technical field of standby power supply discloses a kind of standby power supply circuit of electric drive controller, comprising: power supply unit, for providing initial direct-current voltage;Voltage conversion unit, input and power supply unit connection, for converting initial direct-current voltage into first backup voltage, second backup voltage and third backup voltage, first backup voltage is output to the high voltage domain power supply end of lower bridge drive chip in load unit by first voltage output end, second backup voltage is output to the low voltage domain power supply end of lower bridge drive chip by second voltage output end, third backup voltage is output to the hardware logic protection circuit of load unit by third voltage output end, the utility model can supply power for hardware logic protection circuit and inverter lower bridge drive chip in load unit by first backup voltage, second backup voltage and third backup voltage when chip failure leads to original low voltage power supply system failure, to ensure that electric drive controller enters safe state.

Description

Technical Field

[0001] This utility model relates to the field of backup power technology, and in particular to a backup power circuit for an electric drive controller. Background Technology

[0002] In new energy vehicles, when the low-voltage power supply system of the electric drive controller fails, all the switches in the electric drive controller are in the off state, losing control of the electric drive system. If the vehicle is traveling at high speed at this time, the back electromotive force generated by the motor will charge the high-voltage circuit through the uncontrolled rectifier circuit formed by the anti-parallel diodes in the inverter. In severe cases, this may cause overvoltage damage to the high-voltage section or even lead to a fire. Having one half of the switches in the electric drive controller fully open while the other half is fully closed provides a discharge circuit for the motor, preventing the above problems and considered a safe state.

[0003] To ensure the electric drive controller can still enter a safe state via hardware control even in the event of a low-voltage power supply system failure, a backup power supply circuit is required. The existing power backup scheme backs up the low-voltage input power supply KL30 of the electric drive controller, essentially backing up the battery's input voltage. When the low-voltage input power supply KL30 loses power, the backup power supply replaces KL30, and after voltage conversion by the power chip, provides power to the control circuit of the electric drive controller, ensuring it enters a safe state. However, since various faults in the low-voltage power supply system can lead to system failure, if the power control chip of the original output power supply fails, causing the low-voltage power supply system to fail, the existing method of only backing up the low-voltage input power supply KL30 cannot provide the necessary power to the control circuit, preventing the electric drive controller from entering a safe state. Utility Model Content

[0004] In view of this, the present invention provides a backup power supply circuit for an electric drive controller to solve or partially solve the technical problem in the prior art where the electric drive controller cannot enter a safe state when the power control chip of the original power supply fails, causing the low-voltage power supply system to fail.

[0005] The technical solution proposed by this utility model is as follows: This utility model provides a backup power supply circuit for an electric drive controller, comprising: a power supply unit for providing an initial DC voltage; and a voltage conversion unit, with its input terminal connected to the power supply unit, for converting the initial DC voltage into a first backup voltage, a second backup voltage, and a third backup voltage. The first backup voltage is output to the high-voltage domain power supply terminal of the lower bridge driver chip in the load unit through a first voltage output terminal, the second backup voltage is output to the low-voltage domain power supply terminal of the lower bridge driver chip through a second voltage output terminal, and the third backup voltage is output to the hardware logic protection circuit of the load unit through a third voltage output terminal, wherein the third backup voltage is less than the second backup voltage.

[0006] Optionally, the voltage conversion unit includes: a DC-DC converter circuit, with its input terminal connected to the power supply unit, for converting the initial DC voltage into a first backup voltage and a second backup voltage, the first backup voltage and the second backup voltage being output to a first voltage output terminal and a second voltage output terminal, respectively; and a step-down circuit, with its input terminal connected to the second voltage output terminal and its output terminal connected to the hardware logic protection circuit of the load unit, for stepping down the second backup voltage to convert it into a third backup voltage, the third backup voltage being output to the hardware logic protection circuit of the load unit through the third voltage output terminal.

[0007] Optionally, the DC-DC converter circuit includes: a power supply chip; a high-voltage start-up circuit, with its input terminal connected to the power supply unit and its output terminal connected to the high-voltage start-up pin of the power supply chip; an isolation transformer, including a primary winding, an auxiliary output winding, a low-voltage output winding, and a high-voltage output winding, with the first end of the primary winding connected to the positive terminal of the power supply unit, the second end of the primary winding connected to the negative terminal of the power supply unit via a main circuit switching circuit, the auxiliary output winding used to generate an auxiliary voltage based on the magnetic field change of the primary winding, the low-voltage output winding used to generate a second backup voltage based on the magnetic field change of the primary winding, and the high-voltage output winding used to generate a first backup voltage based on the magnetic field change of the primary winding; a main circuit switching circuit, with its controlled terminal connected to the drive output pin of the power supply chip, and its first and second connection terminals connected to the second end of the primary winding and the negative terminal of the power supply unit, respectively; and an auxiliary winding voltage detection circuit, with one end connected to the second end of the auxiliary output winding and the other end connected to the voltage detection pin of the power supply chip, and the first end of the auxiliary output winding connected to the negative terminal of the power supply unit.

[0008] Optionally, the high-voltage startup circuit includes a first resistor and a first diode. One end of the first resistor is connected to the positive terminal of the power supply unit, and the other end of the first resistor is connected to the negative terminal of the first diode and the high-voltage startup pin of the power supply chip. The positive terminal of the first diode is connected to the negative terminal of the power supply unit. The first diode is a transient voltage suppression diode.

[0009] Optionally, the main circuit switching circuit includes a first field-effect transistor (FET), a second field-effect transistor (FET), a second resistor, a third resistor, a second diode, a third diode, a fourth diode, and a fifth diode. The drain of the first FET is connected to the second terminal of the primary winding of the transformer and the anode of the fifth diode, respectively. The cathode of the fifth diode is connected to the cathode of the fourth diode, and the anode of the fourth diode is connected to the first terminal of the primary winding of the transformer. The source of the first FET and the drain of the second FET are connected. The gate of the second FET is connected to the drive output pin of the power supply chip. The source of the second FET is connected to one end of the third resistor and the current sampling pin of the power supply chip, respectively. The other end of the third resistor is grounded. The anode of the third diode is connected to the source of the first FET. The cathode of the third diode is connected to the gate of the first FET, one end of the second resistor, and the cathode of the second diode, respectively. The other end of the second resistor is connected to the anode of the power supply unit, and the anode of the second diode is connected to the cathode of the power supply unit. The second, third, and fourth diodes are all transient voltage suppression diodes.

[0010] Optionally, the auxiliary winding voltage detection circuit includes a sixth diode and a first capacitor. The positive terminal of the sixth diode is connected to the second end of the auxiliary output winding, the negative terminal of the sixth diode is connected to the voltage detection pin of the power supply chip and one end of the first capacitor, and the other end of the first capacitor is connected to the negative terminal of the power supply unit.

[0011] Optionally, the DC-DC converter circuit further includes a seventh diode, an eighth diode, a second capacitor, a third capacitor, a fourth resistor, and a fifth resistor. The positive terminal of the seventh diode is connected to the second end of the low-voltage output winding. The negative terminal of the seventh diode is connected to one end of the second capacitor, one end of the fourth resistor, and the second voltage output terminal, respectively. The first end of the low-voltage output winding is connected to the other end of the second capacitor, the other end of the fourth resistor, and the ground terminal, respectively. The positive terminal of the eighth diode is connected to the second end of the high-voltage output winding. The negative terminal of the eighth diode is connected to one end of the third capacitor, one end of the fifth resistor, and the first voltage output terminal, respectively. The first end of the high-voltage output winding is connected to the other end of the third capacitor and the ground terminal, respectively. The other end of the fifth resistor is connected to the negative terminal of the power supply unit.

[0012] Optionally, the DC-DC converter circuit also includes an isolation feedback circuit, the input terminal of which is connected to the negative terminal of the eighth diode, and the output terminal of which is connected to the feedback signal input pin of the power supply chip.

[0013] Optionally, the step-down circuit includes a low-dropout linear regulator, the input terminal of which is connected to the second voltage output terminal, and the output terminal of which is connected to the third voltage output terminal. The low-dropout linear regulator is used to step down the second backup voltage and convert it into the third backup voltage.

[0014] Optionally, the backup power supply circuit of the electric drive controller further includes a ninth diode, a tenth diode, and an eleventh diode. The positive terminal of the ninth diode is connected to the second voltage output terminal, the negative terminal of the ninth diode is connected to the low-voltage power supply terminal of the lower bridge driver chip, the positive terminal of the tenth diode is connected to the third voltage output terminal, the negative terminal of the tenth diode is connected to the hardware logic protection circuit, the positive terminal of the eleventh diode is connected to the first voltage output terminal, and the negative terminal of the eleventh diode is connected to the high-voltage power supply terminal of the bridge driver chip.

[0015] This utility model has the following beneficial effects: The backup power circuit of the electric drive controller of this utility model converts the initial DC voltage output by the power supply unit into a first backup voltage, a second backup voltage, and a third backup voltage through a voltage conversion unit. These backup voltages are then output to the high-voltage domain power supply terminal, the low-voltage domain power supply terminal, and the hardware logic protection circuit of the lower bridge driver chip in the load unit through the first voltage output terminal, the second voltage output terminal, and the third voltage output terminal, respectively. When the original low-voltage power supply system fails due to chip failure, the hardware logic protection circuit and the inverter lower bridge driver chip in the load unit can be powered by the first backup voltage, the second backup voltage, and the third backup voltage to ensure that the electric drive controller enters a safe state. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a circuit block diagram of the backup power supply circuit of the electric drive controller according to an embodiment of the present utility model. Figure 2 This is a circuit diagram of the backup power supply circuit of the electric drive controller according to an embodiment of the present invention. Explanation of reference numerals in the attached figures: 1-Power supply unit; 2-Voltage conversion unit; 3-Load unit; R1-First resistor; R2-Second resistor; R3-Third resistor; R4-Fourth resistor; R5-Fifth resistor; D1-First diode; D2-Second diode; D3-Third diode; D4-Fourth diode; D5-Fifth diode; D6-Sixth diode; D7-Seventh diode; D8-Eighth diode; D9-Ninth diode; D10-Tenth diode; D11-Eleventh diode; C1-First capacitor; C2-Second capacitor; C3-Third capacitor; Q1-First field-effect transistor; Q2-Second field-effect transistor. Detailed Implementation

[0018] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0019] In the description of this utility model, it should be noted that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0020] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can also refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0021] Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0022] like Figure 1 and Figure 2 As shown, the backup power supply circuit of the electric drive controller in this embodiment of the present invention includes: A backup power supply circuit for an electric drive controller includes: a power supply unit 1 for providing an initial DC voltage; and a voltage conversion unit 2, with its input terminal connected to the power supply unit, for converting the initial DC voltage into a first backup voltage, a second backup voltage, and a third backup voltage. The first backup voltage is output to the high-voltage domain power supply terminal of the lower bridge driver chip in the load unit 3 through a first voltage output terminal V1+, the second backup voltage is output to the low-voltage domain power supply terminal of the lower bridge driver chip through a second voltage output terminal V2+, and the third backup voltage is output to the hardware logic protection circuit of the load unit 3 through a third voltage output terminal V3+, wherein the third backup voltage is less than the second backup voltage.

[0023] Specifically, power supply unit 1 includes a power battery pack, which provides energy to the entire backup power circuit. The initial DC voltage output by power supply unit 1 is a high voltage of several hundred volts.

[0024] Voltage conversion unit 2 is responsible for converting the high voltage of the power battery pack (several hundred volts) to the voltage of tens or a few volts required by load unit 3, including a first backup voltage, a second backup voltage, and a third backup voltage. In one example, the first backup voltage is +15V, the second backup voltage is +12V, and the third backup voltage is +5V.

[0025] Load unit 3 includes a hardware logic protection circuit, a lower bridge driver chip of the inverter, and a lower bridge switch. When a fault occurs, the hardware logic protection circuit provides an enable signal and a control signal for the lower bridge driver chip to enable the safe state. After enabling the safe state, the lower bridge driver chip outputs the corresponding gate level to control the lower bridge switch according to the safe state control signal.

[0026] When the high voltage of the electric drive controller is turned on, once the bus voltage reaches the start-up voltage of the voltage conversion unit 2, the voltage conversion unit 2 starts to work, outputting the first backup voltage to the high voltage domain power supply terminal through the first voltage output terminal V1+, outputting the second backup voltage to the low voltage domain power supply terminal through the second voltage output terminal V2+, and outputting the third backup voltage to the hardware logic protection circuit through the third voltage output terminal V3+.

[0027] It should be understood that the high-voltage domain power supply terminal, low-voltage domain power supply terminal, and hardware logic protection circuit of the lower bridge driver chip are also connected to their respective original power supplies. Specifically, the high-voltage domain power supply terminal is connected to both the first voltage output terminal V1+ and the original high-voltage domain power supply; the low-voltage domain power supply terminal is connected to both the second voltage output terminal V2+ and the original low-voltage domain power supply. The hardware logic protection circuit is connected to both the third voltage output terminal V3+ and the original power supply for the hardware logic protection circuit. The voltages of the corresponding original power supplies are all higher than the first backup voltage, the second backup voltage, and the third backup voltage. When the original power supply is outputting normally, the voltage conversion unit 2 does not provide power externally.

[0028] When the low-voltage power supply system of the electric drive controller fails, the original power supply gradually decreases. Once it reaches the voltage of the backup power supply—that is, the voltages of the original power supply in the high-voltage domain, the original power supply in the low-voltage domain, and the original power supply of the hardware logic protection circuit all drop to the first backup voltage, the second backup voltage, or the third backup voltage—the subsequent power supply will be provided by voltage conversion unit 2. At this time, neither the low-voltage domain nor the high-voltage domain of the hardware fault logic protection circuit or the lower-bridge driver chip loses power. The hardware fault logic protection circuit outputs a safety state enable signal to put the lower-bridge driver chip into a safety state and outputs a safety state control signal to control the high-voltage domain to output a high level, thus enabling all lower-bridge components of the electric drive controller to be turned on and enter a safety state.

[0029] The backup power circuit of the electric drive controller of this utility model converts the initial DC voltage output by the power supply unit 1 into a first backup voltage, a second backup voltage, and a third backup voltage through the voltage conversion unit 2. These backup voltages are then output to the high-voltage domain power supply terminal, the low-voltage domain power supply terminal, and the hardware logic protection circuit of the lower bridge driver chip in the load unit 3 through the first voltage output terminal V1+, the second voltage output terminal V2+, and the third voltage output terminal V3+, respectively. When the original low-voltage power supply system fails due to chip failure, the hardware logic protection circuit and the inverter lower bridge driver chip in the load unit 3 can be powered by the first backup voltage, the second backup voltage, and the third backup voltage to ensure that the electric drive controller enters a safe state.

[0030] In some embodiments, the voltage conversion unit 2 includes: a DC-DC converter circuit, whose input terminal is connected to the power supply unit 1, for converting the initial DC voltage into a first backup voltage and a second backup voltage, the first backup voltage and the second backup voltage being output to the first voltage output terminal V1+ and the second voltage output terminal V2+, respectively; and a step-down circuit, whose input terminal is connected to the second voltage output terminal V2+ and whose output terminal is connected to the hardware logic protection circuit of the load unit 3, for stepping down the second backup voltage to convert it into a third backup voltage, the third backup voltage being output to the hardware logic protection circuit of the load unit 3 through the third voltage output terminal V3+.

[0031] Specifically, a DC-DC converter circuit is a circuit that converts one type of DC voltage into another type of DC voltage output. It can employ flyback converter circuits, forward converter circuits, buck-boost converter circuits, etc. For example, a DC-DC converter circuit uses a flyback converter circuit.

[0032] The step-down circuit is used to further step down the second backup voltage, which has a lower voltage value, to obtain a third backup voltage, thereby achieving a more stable voltage output.

[0033] In this embodiment of the invention, the DC-DC converter circuit can efficiently convert the initial DC voltage into a first backup voltage and a second backup voltage, while the step-down circuit further steps down the second backup voltage to a third backup voltage. This step-by-step conversion method can output a more stable backup voltage.

[0034] In some embodiments, the DC-DC converter circuit includes: a power supply chip; a high-voltage startup circuit, with its input terminal connected to the power supply unit 1 and its output terminal connected to the high-voltage startup pin of the power supply chip; and an isolation transformer, including a primary winding, an auxiliary output winding, a low-voltage output winding, and a high-voltage output winding. The first terminal of the primary winding is connected to the positive (DC+) terminal of the power supply unit 1, and the second terminal is connected to the negative (DC-) terminal of the power supply unit 1 via a main circuit switching circuit. The auxiliary output winding is used to generate an auxiliary voltage based on the magnetic field change of the primary winding. The output winding is used to generate a second backup voltage based on the magnetic field change of the primary winding of the transformer, and the high-voltage output winding is used to generate a first backup voltage based on the magnetic field change of the primary winding of the transformer; the main circuit switching circuit is connected to the controlled terminal and the drive output pin of the power chip, and the first connection terminal and the second connection terminal are respectively connected to the second terminal of the primary winding of the transformer and the negative DC- of the power supply unit 1; the auxiliary winding voltage detection circuit is connected to the second terminal of the auxiliary output winding at one end and to the voltage detection pin of the power chip at the other end, and the first terminal of the auxiliary output winding is connected to the negative DC- of the power supply unit 1.

[0035] Specifically, an isolation transformer is used to achieve voltage conversion. The first backup voltage and the second backup voltage can be output simultaneously through the low-voltage output winding and the high-voltage output winding, realizing two backup voltage outputs. The primary winding of the transformer generates auxiliary voltage, second backup voltage and first backup voltage through magnetic field changes, achieving a high degree of functional integration and reducing the number and complexity of circuit components.

[0036] Meanwhile, the auxiliary output winding can be used for auxiliary functions such as voltage detection, further improving the intelligence level of the circuit.

[0037] The power supply chip is model UCC28740-Q1. The main circuit switching circuit is controlled by the drive output pin of the power supply chip. It can switch the primary winding of the transformer between charging and discharging states by controlling the on / off state of the main circuit switching circuit, thereby realizing voltage conversion control. At the same time, the auxiliary winding voltage detection circuit can monitor the changes in auxiliary voltage in real time, providing feedback signals to the power supply chip to realize dynamic protection and regulation of the circuit.

[0038] Furthermore, the high-voltage startup circuit includes a first resistor R1 and a first diode D1. One end of the first resistor R1 is connected to the positive DC+ terminal of the power supply unit 1, and the other end of the first resistor R1 is connected to the negative terminal of the first diode D1 and the high-voltage startup pin of the power supply chip. The positive terminal of the first diode D1 is connected to the negative DC- terminal of the power supply unit 1. The first diode D1 is a transient voltage suppression diode (TVS).

[0039] Specifically, the voltage input to the high-voltage start-up pin of the power chip can be limited by the first diode D1, and the current flowing through the first diode D1 can be limited by the first resistor R1.

[0040] The high-voltage startup circuit uses a combination of a first resistor R1 and a first diode D1 to quickly provide startup voltage to the high-voltage startup pin of the power chip, ensuring rapid circuit startup. Simultaneously, the first diode D1 is a transient voltage suppression diode, effectively suppressing transient voltage surges during startup and protecting the power chip from damage.

[0041] Furthermore, the main circuit switching circuit includes a first field-effect transistor Q1, a second field-effect transistor Q2, a second resistor R2, a third resistor R3, a second diode D2, a third diode D3, a fourth diode D4, and a fifth diode D5. The drain of the first field-effect transistor Q1 is connected to the second terminal of the primary winding of the transformer and the anode of the fifth diode D5. The cathode of the fifth diode D5 is connected to the cathode of the fourth diode D4. The anode of the fourth diode D4 is connected to the first terminal of the primary winding of the transformer. The source of the first field-effect transistor Q1 is connected to the drain of the second field-effect transistor Q2. The gate of the second field-effect transistor Q2 is connected to the drive output pin of the power supply chip. The source of the second field-effect transistor Q2 is connected to one end of the third resistor R3 and the current sampling pin of the power supply chip, respectively. The other end of the third resistor R3 is grounded. The anode of the third diode D3 is connected to the source of the first field-effect transistor Q1. The cathode of the third diode D3 is connected to the gate of the first field-effect transistor Q1, one end of the second resistor R2 and the cathode of the second diode D2, respectively. The other end of the second resistor R2 is connected to the positive DC+ terminal of the power supply unit 1. The anode of the second diode D2 is connected to the negative DC- terminal of the power supply unit 1. The second diode D2, the third diode D3 and the fourth diode D4 are all transient voltage suppression diodes.

[0042] Specifically, the fifth diode, D5, is a fast recovery diode.

[0043] The first field-effect transistor Q1 and the second field-effect transistor Q2 are both metal-oxide-semiconductor field-effect transistors (MOSFETs).

[0044] The drain of the first field-effect transistor Q1 is connected to the first end of the primary winding of the transformer, and the source is connected to the drain of the second field-effect transistor Q2. The second field-effect transistor Q2 is controlled by the power supply chip, and the first field-effect transistor Q1 is controlled by a control circuit consisting of a second resistor R2, a second diode D2, and a third diode D3. A fourth diode D4 and a fifth diode D5 form an absorption circuit, and the absorption loop is connected to both ends of the primary winding of the transformer.

[0045] The third resistor R3 is the current sampling resistor of the primary winding of the transformer. It is connected between the source of the second field-effect transistor Q2 and the negative terminal DC- of the power supply unit 1. The voltage across the third resistor R3 provides feedback on the magnitude of the current in the primary winding of the transformer.

[0046] The main circuit switching circuit employs the coordinated control of the first field-effect transistor Q1 and the second field-effect transistor Q2, enabling precise control of the transformer primary winding current and improving voltage conversion efficiency and stability. Simultaneously, the gate voltage of the field-effect transistors can be adjusted through the cooperation of multiple resistors and diodes, further optimizing circuit performance.

[0047] The second diode D2, the third diode D3, and the fourth diode D4 are all transient voltage suppression diodes, which can effectively suppress transient voltage fluctuations in the circuit and protect the field-effect transistor and other circuit components from overvoltage damage.

[0048] The source of the second field-effect transistor Q2 is connected to the current sampling pin of the power supply chip, which enables real-time sampling and feedback of the main circuit current, facilitating dynamic current adjustment and further improving the safety and performance of the circuit.

[0049] Furthermore, the auxiliary winding voltage detection circuit includes a sixth diode D6 and a first capacitor C1. The positive terminal of the sixth diode D6 is connected to the second end of the auxiliary output winding, the negative terminal of the sixth diode D6 is connected to the voltage detection pin of the power supply chip and one end of the first capacitor C1, and the other end of the first capacitor C1 is connected to the negative DC- terminal of the power supply unit 1.

[0050] Specifically, the sixth diode D6 serves as the rectifier diode of the auxiliary output winding to rectify its output current, and the first capacitor C1 serves as the output capacitor of the auxiliary output winding, which can stabilize the output voltage and improve the accuracy and stability of voltage detection.

[0051] Optionally, the DC-DC converter circuit further includes a seventh diode D7, an eighth diode D8, a second capacitor C2, a third capacitor C3, a fourth resistor R4, and a fifth resistor R5. The positive terminal of the seventh diode D7 is connected to the second end of the low-voltage output winding. The negative terminal of the seventh diode D7 is connected to one end of the second capacitor C2, one end of the fourth resistor R4, and the second voltage output terminal V2+. The first end of the low-voltage output winding is connected to the other end of the second capacitor C2, the other end of the fourth resistor R4, and the ground terminal. The positive terminal of the eighth diode D8 is connected to the second end of the high-voltage output winding. The negative terminal of the eighth diode D8 is connected to one end of the third capacitor C3, one end of the fifth resistor R5, and the first voltage output terminal V1+. The first end of the high-voltage output winding is connected to the other end of the third capacitor C3 and the ground terminal. The other end of the fifth resistor R5 is connected to the negative terminal DC- of the power supply unit 1.

[0052] Specifically, diodes D7 (seventh diode) and D8 (eighth diode) serve as rectifier diodes for the low-voltage and high-voltage output windings, respectively. Capacitors C2 (second capacitor) and C3 (third capacitor) are the output capacitors for the low-voltage and high-voltage output windings, respectively, connected to their positive and negative terminals. Through these components, the voltages generated by the low-voltage and high-voltage output windings are rectified and filtered, improving the stability of the output voltage and meeting the power supply requirements of loads such as the lower bridge driver chip.

[0053] The fourth resistor R4 and the fifth resistor R5 serve as dummy loads for the low-voltage and high-voltage outputs, respectively, connected in parallel across their respective output capacitors. The addition of these resistors enables fine-tuning of the output voltage and provides current-limiting protection, preventing circuit damage caused by short circuits or overloads, thus further improving the stability and reliability of the backup power supply circuit.

[0054] In some embodiments, the DC-DC converter circuit further includes an isolation feedback circuit, the input terminal of which is connected to the negative terminal of the eighth diode D8, and the output terminal of which is connected to the feedback signal input pin of the power supply chip.

[0055] Specifically, the isolation feedback circuit is used to acquire the voltage signal output from the high-voltage domain. The input terminal U3A and the output terminal U3B of the isolation feedback circuit are connected to the negative terminal of the eighth diode D8 and the feedback signal input pin of the power supply chip, respectively.

[0056] In one example, the isolation feedback circuit includes a sampling resistor, with the input terminal U3A and the output terminal U3B of the isolation feedback circuit being the two ends of the sampling resistor.

[0057] This invention uses an isolation feedback circuit to feed back the voltage signal from the negative terminal of the eighth diode D8 to the power supply chip, thereby achieving closed-loop control of the voltage conversion process, ensuring the stability and accuracy of the output voltage, and improving the dynamic performance and adaptability of the backup power supply circuit.

[0058] In some embodiments, the step-down circuit includes a low dropout regulator (LDO), the input terminal of which is connected to the second voltage output terminal V2+, and the output terminal of which is connected to the third voltage output terminal V3+. The LDO is used to step down the second backup voltage and convert it into the third backup voltage.

[0059] A low-dropout linear regulator (LDL-LEF) is a voltage regulator that operates with a very small difference between the input and output voltages. By using an LDL-LEF as a step-down circuit, a stable step-down function can be achieved with a low input-output voltage difference, improving the efficiency and stability of the step-down circuit. Simultaneously, the LDL-LEF exhibits excellent load regulation and line regulation, effectively suppressing the impact of input voltage fluctuations and load changes on the output voltage, ensuring the stability and reliability of the third backup voltage.

[0060] In some embodiments, the backup power supply circuit of the electric drive controller further includes a ninth diode D9, a tenth diode D10, and an eleventh diode D11. The positive terminal of the ninth diode D9 is connected to the second voltage output terminal V2+, the negative terminal of the ninth diode D9 is connected to the low-voltage power supply terminal of the lower bridge driver chip, the positive terminal of the tenth diode D10 is connected to the third voltage output terminal V3+, the negative terminal of the tenth diode D10 is connected to the hardware logic protection circuit, the positive terminal of the eleventh diode D11 is connected to the first voltage output terminal V1+, and the negative terminal of the eleventh diode D11 is connected to the high-voltage power supply terminal of the bridge driver chip.

[0061] Specifically, the ninth diode D9, the tenth diode D10, and the eleventh diode D11 are respectively the isolation between the low-voltage domain backup power supply, the hardware logic protection circuit backup power supply, and the high-voltage domain backup power supply and the original power supply, and are respectively connected to the second voltage output terminal V2+, the third voltage output terminal V3+, and the first voltage output terminal V1+ and their respective original power supplies.

[0062] By incorporating diodes D9 (ninth), D10 (tenth), and D11 (eleventh), isolation and protection between the output terminals and the load at different voltage levels can be achieved. These diodes prevent current backflow from the load side during normal operation of the original power supply, thus improving the safety and reliability of the circuit.

[0063] The working principle of the backup power supply circuit of the electric drive controller in this embodiment of the present invention is as follows: The power chip's drive output pin outputs a square wave signal to control the on / off state of the second field-effect transistor Q2. When Q2 is on, the gate voltage of the first field-effect transistor Q1 is limited by the third diode D3, causing Q1 to turn on and thus the primary circuit to conduct. At this time, the sixth diode D6, the seventh diode D7, and the eighth diode D8 are reverse-biased and cut off, allowing the transformer's primary winding to store energy.

[0064] When the second MOSFET Q2 is turned off, the voltage between its drain and source gradually increases. When this voltage exceeds the voltage across the second diode D2, the third diode D3 forward-biased conducts, clamping the drain voltage of the second diode D2. The first MOSFET Q1 is then turned off, and the remaining voltage is handled by Q1. This shuts off the main circuit. The sixth diode D6, the seventh diode D7, and the eighth diode D8 then conduct, transferring energy from the primary side to the secondary side—that is, from the primary winding of the transformer to the auxiliary output winding, the low-voltage output winding, and the high-voltage output winding.

[0065] The isolation feedback circuit collects the voltage value of the high-voltage domain output through the negative terminal of the eighth diode D8. The power chip adjusts the duty cycle according to the feedback voltage value to stabilize the output voltage.

[0066] This utility model provides a backup power supply circuit for an electric drive controller. Compared to the traditional method of backing up the main low-voltage power supply KL30, this circuit can cover the failure of the low-voltage power supply system caused by power chip failure, thus further increasing the protection scope.

[0067] The DC-DC converter and step-down circuit output multiple backup voltages with different values. When the original power supply fails to provide normal power, backup power is provided for the hardware logic protection circuit, the low-voltage domain and the high-voltage domain of the inverter lower bridge. The backup power coverage is comprehensive, ensuring that the electric drive controller can smoothly enter a safe state when the original power supply fails. The overall circuit structure is also simple.

[0068] Although the exemplary embodiments and their advantages have been described in detail, those skilled in the art can make various changes, substitutions and modifications to these embodiments without departing from the spirit and scope of protection of this utility model, and such modifications and variations all fall within the scope defined by the present invention.

Claims

1. A backup power supply circuit for an electric drive controller, characterized in that, include: The power supply unit is used to provide the initial DC voltage; A voltage conversion unit, with its input terminal connected to the power supply unit, is used to convert the initial DC voltage into a first backup voltage, a second backup voltage, and a third backup voltage. The first backup voltage is output to the high-voltage domain power supply terminal of the lower bridge driver chip in the load unit through a first voltage output terminal. The second backup voltage is output to the low-voltage domain power supply terminal of the lower bridge driver chip through a second voltage output terminal. The third backup voltage is output to the hardware logic protection circuit of the load unit through a third voltage output terminal. The third backup voltage is less than the second backup voltage.

2. The backup power supply circuit for the electric drive controller according to claim 1, characterized in that, The voltage conversion unit includes: The DC-DC converter circuit has its input terminal connected to the power supply unit and is used to convert the initial DC voltage into the first backup voltage and the second backup voltage. The first backup voltage and the second backup voltage are respectively output to the first voltage output terminal and the second voltage output terminal. The step-down circuit has its input terminal connected to the second voltage output terminal and its output terminal connected to the hardware logic protection circuit of the load unit. It is used to step down the second backup voltage and convert it into a third backup voltage. The third backup voltage is output to the hardware logic protection circuit of the load unit through the third voltage output terminal.

3. The backup power supply circuit for the electric drive controller according to claim 2, characterized in that, The DC-DC converter circuit includes: Power chip; The high-voltage start-up circuit has its input terminal connected to the power supply unit and its output terminal connected to the high-voltage start-up pin of the power chip. An isolation transformer includes a primary winding, an auxiliary output winding, a low-voltage output winding, and a high-voltage output winding. The first end of the primary winding is connected to the positive terminal of the power supply unit, and the second end of the primary winding is connected to the negative terminal of the power supply unit via a main circuit switching circuit. The auxiliary output winding generates an auxiliary voltage based on changes in the magnetic field of the primary winding. The low-voltage output winding generates a second backup voltage based on changes in the magnetic field of the primary winding. The high-voltage output winding generates a first backup voltage based on changes in the magnetic field of the primary winding. The main circuit switching circuit has its controlled terminal connected to the drive output pin of the power chip, and its first connection terminal and second connection terminal connected to the second terminal of the primary winding of the transformer and the negative terminal of the power supply unit, respectively. An auxiliary winding voltage detection circuit has one end connected to the second end of the auxiliary output winding and the other end connected to the voltage detection pin of the power supply chip. The first end of the auxiliary output winding is connected to the negative terminal of the power supply unit.

4. The backup power supply circuit for the electric drive controller according to claim 3, characterized in that, The high-voltage startup circuit includes a first resistor and a first diode. One end of the first resistor is connected to the positive terminal of the power supply unit, and the other end of the first resistor is connected to the negative terminal of the first diode and the high-voltage startup pin of the power chip. The positive terminal of the first diode is connected to the negative terminal of the power supply unit. The first diode is a transient voltage suppression diode.

5. The backup power supply circuit for the electric drive controller according to claim 3, characterized in that, The main circuit switching circuit includes a first field-effect transistor (FET), a second field-effect transistor (FET), a second resistor, a third resistor, a second diode, a third diode, a fourth diode, and a fifth diode. The drain of the first FET is connected to the second terminal of the primary winding of the transformer and the anode of the fifth diode. The cathode of the fifth diode is connected to the cathode of the fourth diode. The anode of the fourth diode is connected to the first terminal of the primary winding of the transformer. The source of the first FET is connected to the drain of the second FET. The gate of the second FET is connected to the drive output pin of the power supply chip. The source of the second FET is connected to one end of the third resistor and the current sampling pin of the power supply chip. The other end of the third resistor is grounded. The anode of the third diode is connected to the source of the first FET. The cathode of the third diode is connected to the gate of the first FET, one end of the second resistor, and the cathode of the second diode. The other end of the second resistor is connected to the anode of the power supply unit. The anode of the second diode is connected to the cathode of the power supply unit. The second, third, and fourth diodes are all transient voltage suppression diodes.

6. The backup power supply circuit for the electric drive controller according to claim 3, characterized in that, The auxiliary winding voltage detection circuit includes a sixth diode and a first capacitor. The positive terminal of the sixth diode is connected to the second end of the auxiliary output winding, the negative terminal of the sixth diode is connected to the voltage detection pin of the power chip and one end of the first capacitor, and the other end of the first capacitor is connected to the negative terminal of the power supply unit.

7. The backup power supply circuit for the electric drive controller according to claim 3, characterized in that, The DC-DC converter circuit further includes a seventh diode, an eighth diode, a second capacitor, a third capacitor, a fourth resistor, and a fifth resistor. The anode of the seventh diode is connected to the second terminal of the low-voltage output winding. The cathode of the seventh diode is connected to one end of the second capacitor, one end of the fourth resistor, and the second voltage output terminal. The first terminal of the low-voltage output winding is connected to the other end of the second capacitor, the other end of the fourth resistor, and ground. The anode of the eighth diode is connected to the second terminal of the high-voltage output winding. The cathode of the eighth diode is connected to one end of the third capacitor, one end of the fifth resistor, and the first voltage output terminal. The first terminal of the high-voltage output winding is connected to the other end of the third capacitor and ground. The other end of the fifth resistor is connected to the cathode of the power supply unit.

8. The backup power supply circuit for the electric drive controller according to claim 7, characterized in that, The DC-DC converter circuit also includes an isolation feedback circuit. The input terminal of the isolation feedback circuit is connected to the negative terminal of the eighth diode, and the output terminal of the isolation feedback circuit is connected to the feedback signal input pin of the power chip.

9. The backup power supply circuit for the electric drive controller according to claim 2, characterized in that, The step-down circuit includes a low-dropout linear regulator. The input terminal of the low-dropout linear regulator is connected to the second voltage output terminal, and the output terminal of the low-dropout linear regulator is connected to the third voltage output terminal. The low-dropout linear regulator is used to step down the second backup voltage and convert it into the third backup voltage.

10. The backup power supply circuit for the electric drive controller according to claim 1, characterized in that, It also includes a ninth diode, a tenth diode, and an eleventh diode. The anode of the ninth diode is connected to the second voltage output terminal, and the cathode of the ninth diode is connected to the low-voltage power supply terminal of the lower bridge driver chip. The anode of the tenth diode is connected to the third voltage output terminal, and the cathode of the tenth diode is connected to the hardware logic protection circuit. The anode of the eleventh diode is connected to the first voltage output terminal, and the cathode of the eleventh diode is connected to the high-voltage power supply terminal of the bridge driver chip.

Images