A three-phase inverter asynchronous control circuit

Abstract

The utility model relates to inverter control circuit technical field, concretely is a kind of three-phase inverter asynchronous control circuit, comprising: MCU, switch and logic control circuit, current sampling module, three-phase full bridge circuit, high-voltage bus capacitor, high-voltage battery;The current sampling module is used to collect the instantaneous value of the three-phase full bridge circuit output current, and the current instantaneous value collected is fed back to the MCU;The MCU is connected with the switch and logic control circuit signal;The switch and logic control circuit are connected with the three-phase full bridge circuit signal;The two ends of the high-voltage bus capacitor and high-voltage battery are respectively connected in parallel on the voltage input end+ and voltage input end- of the three-phase full bridge circuit.Electric motor controller three-phase current instantaneous value is judged as the basis to realize the independent switching of the switch configuration of three-phase full bridge circuit, and different instantaneous current can be realized simultaneously using different switch configuration to reach the optimal loss.

Description

Technical Field

[0001] This utility model relates to the field of inverter control circuit technology, specifically to an asynchronous control circuit for a three-phase inverter. Background Technology

[0002] With the development of new energy vehicle technology, the requirements for the power level and efficiency of motor controllers are becoming increasingly stringent. Traditional Si-based IGBT modules have limited output capabilities, high losses, low efficiency, and cannot operate at very high switching frequencies. Therefore, SiC power modules have been extensively researched and used. SiC power modules can significantly improve power levels, reduce losses, and increase system efficiency, thereby extending driving range. However, SiC power modules are very expensive and in short supply. To address these issues, hybrid power modules combining SiC transistors and IGBT transistors have been gradually developed. The overall performance of hybrid modules falls between that of SiC transistors and IGBT transistors. Their respective advantages and disadvantages are shown in the table below:

[0003] SiC transistors have the following advantages: low switching losses, positive temperature coefficient which is beneficial for current sharing, high temperature resistance, and low thermal resistance. They also have the following disadvantages: high conduction losses at high temperatures and high currents, weak short-circuit capability, unstable threshold voltage, gate oxidation problems, and high cost.

[0004] IGBT transistors have the following advantages: low conduction loss under high temperature and high current, strong short-circuit capability, stable threshold voltage, more mature solutions, and low cost. However, they also have disadvantages such as relatively large switching losses, positive and negative temperature coefficients throughout the current range, and the negative temperature coefficient region being unfavorable for current sharing.

[0005] To better leverage the optimal performance of each hybrid power module, a dedicated driver adapted for hybrid modules has been developed. Specific performance requirements are as follows:

[0006] The drive power supply voltages for both SiC and IGBT are adjustable.

[0007] The switching sequence of SiC and IGBT needs to be adjustable according to conditions such as junction temperature;

[0008] The switching delay time of SiC and IGBT is adjustable, thus preventing a single device from bearing the full large current for an extended period of time.

[0009] like Figure 1 The figure shows a PWM waveform diagram of a common switching strategy configuration for hybrid power modules in the prior art;

[0010] like Figure 2 The diagram shows the delay time definition (Tdelayon, Tdelayoff) of a hybrid power module on a PWM waveform diagram in the prior art.

[0011] like Figure 3The diagram shown is a schematic of the synchronous switching control principle of existing hybrid power modules, as follows: Figure 3 As shown, the effective value of the phase current is calculated by using the current sampling inside the motor controller. The switch configuration status is determined based on the effective value of the phase current, and the same configuration signal is sent to the three-phase bridge arm to realize the synchronous switching configuration of the 6 power devices.

[0012] This solution is relatively simple to control, requiring only one switch configuration signal to switch all devices. The software algorithm is also relatively simple, but it sacrifices the performance of the hybrid module. Using the effective value of the three-phase current as the criterion for judgment will cause different instantaneous currents under high current to use the same switch configuration, resulting in greater losses.

[0013] In view of this, we propose an asynchronous control circuit for a three-phase inverter. Utility Model Content

[0014] The purpose of this invention is to provide an asynchronous control circuit for a three-phase inverter to solve the problems mentioned in the background art.

[0015] To achieve the above objectives, this utility model provides the following technical solution:

[0016] An asynchronous control circuit for a three-phase inverter includes: an MCU, a switching and logic control circuit, a current sampling module, a three-phase full-bridge circuit, a high-voltage bus capacitor, and a high-voltage battery. The current sampling module is used to collect the instantaneous value of the output current of the three-phase full-bridge circuit and feed the collected instantaneous current value back to the MCU. The MCU is signal-connected to the switching and logic control circuit. The switching and logic control circuit is signal-connected to the three-phase full-bridge circuit. The two ends of the high-voltage bus capacitor and the high-voltage battery are respectively connected in parallel to the voltage input terminals + and - of the three-phase full-bridge circuit.

[0017] Preferably, the current sampling module collects the instantaneous values ​​of the U-phase, V-phase, and W-phase output currents of the three-phase full-bridge circuit in three separate channels.

[0018] Preferably, the control signal output terminals PWM_UH, PWM_UL, PWM_VH, PWM_VL, PWM_WH, PWM_WL, Smple_UH, Smple_UL, Smple_VH, Smple_VL, Smple_WH, and Smple_WL of the MCU are respectively connected to the signal input terminals of the switch and the logic control circuit.

[0019] Preferably, the signals VgsUH_SiC, VgsUL_SiC, VgeUH_IGBT, VgeUL_IGBT, VgsVH_SiC, VgsVL_SiC, VgeVH_IGBT, VgeVL_IGBT, VgsWH_SiC, VgsWL_SiC, VgeWH_IGBT, and VgeWL_IGBT of the switch and logic control circuit are respectively connected to the U-phase, V-phase, and W-phase signal input terminals of the three-phase full-bridge circuit.

[0020] Preferably, the U-phase, V-phase, and W-phase signal input terminals of the three-phase full-bridge circuit include: the gate of the U-phase upper bridge SiC transistor, the gate of the U-phase upper bridge IGBT transistor, the gate of the U-phase lower bridge SiC transistor, the gate of the U-phase lower bridge IGBT transistor, the gate of the V-phase upper bridge SiC transistor, the gate of the V-phase upper bridge IGBT transistor, the gate of the V-phase lower bridge SiC transistor, the gate of the V-phase lower bridge IGBT transistor, the gate of the W-phase upper bridge SiC transistor, the gate of the W-phase upper bridge IGBT transistor, the gate of the W-phase lower bridge SiC transistor, and the gate of the W-phase lower bridge IGBT transistor.

[0021] Compared with the prior art, the beneficial effects of this utility model are as follows: the asynchronous control circuit of the three-phase inverter uses an MCU to switch the configuration, which is used to configure different switching sequences and switching delay times; the three-phase full-bridge circuit is used for DC-AC conversion of the high-voltage battery; the current sampling module is used to collect the instantaneous values ​​of the U-phase, V-phase, and W-phase currents of the three-phase full-bridge circuit, and uses the instantaneous values ​​of the three-phase currents as the basis for judgment to realize the independent switching of the switching configuration of the three-phase full-bridge circuit. At the same time, different switching configurations can be used for different instantaneous currents to achieve optimal loss. Attached Figure Description

[0022] Figure 1 Configure PWM waveform diagrams for common switching strategies in existing hybrid power modules;

[0023] Figure 2 This defines the delay time (Tdelayon, Tdelayoff) for hybrid power modules in the prior art as displayed on the PWM waveform diagram.

[0024] Figure 3 This is a schematic diagram of the synchronous switching control principle for existing hybrid power modules.

[0025] Figure 4 This is a block diagram illustrating the asynchronous switching control principle of the hybrid power module in this utility model.

[0026] Figure 5 This is a circuit diagram illustrating the asynchronous switching control principle of the hybrid power module in this invention.

[0027] Figure 6 This is a circuit diagram of the switch and logic control circuit in this utility model;

[0028] Figure 7 The diagram shows the sine wave of the switching logic current in the U-phase example of this invention. Detailed Implementation

[0029] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0030] In the description of this patent, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection or setting, a detachable connection or setting, or an integral connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this patent according to the specific circumstances.

[0031] An asynchronous control circuit for a three-phase inverter, such as Figure 4 As shown, the system includes: an MCU, a switch and logic control circuit, a current sampling module, a three-phase full-bridge circuit, a high-voltage bus capacitor, and a high-voltage battery. The current sampling module collects the instantaneous values ​​of the U-phase, V-phase, and W-phase output currents of the three-phase full-bridge circuit in three separate channels and feeds back the collected instantaneous current values ​​to the MCU. The MCU is signal-connected to the switch and logic control circuit. The switch and logic control circuit is signal-connected to the three-phase full-bridge circuit. The two ends of the high-voltage bus capacitor and the high-voltage battery are respectively connected in parallel to the voltage input terminals + and - of the three-phase full-bridge circuit.

[0032] Furthermore, such as Figure 5As shown, the control signal output terminals PWM_UH, PWM_UL, PWM_VH, PWM_VL, PWM_WH, PWM_WL, Smple_UH, Smple_UL, Smple_VH, Smple_VL, Smple_WH, and Smple_WL of the MCU are respectively connected to the signal input terminals of the switch and logic control circuit. The signals VgsUH_SiC, VgsUL_SiC, VgeUH_IGBT, VgeUL_IGBT, VgsVH_SiC, VgsVL_SiC, VgeVH_IGBT, VgeVL_IGBT, VgsWH_SiC, VgsWL_SiC, VgeWH_IGBT, and VgeWL_IGBT of the switch and logic control circuit are respectively connected to the U-phase, V-phase, and W-phase signal input terminals of the three-phase full-bridge circuit. The U-phase, V-phase, and W-phase signal input terminals of the three-phase full-bridge circuit include: the gates of the U-phase upper-bridge SiC transistor, the U-phase upper-bridge IGBT transistor, the U-phase lower-bridge SiC transistor, the V-phase upper-bridge SiC transistor, the V-phase upper-bridge IGBT transistor, the V-phase lower-bridge SiC transistor, the W-phase upper-bridge SiC transistor, the W-phase lower-bridge SiC transistor, and the W-phase lower-bridge IGBT transistor. Specifically, the three-phase full-bridge circuit includes: the U-phase upper-bridge SiC transistor and IGBT transistor, the U-phase lower-bridge SiC transistor and IGBT transistor, the V-phase upper-bridge SiC transistor and IGBT transistor, the V-phase lower-bridge SiC transistor and IGBT transistor, the W-phase upper-bridge SiC transistor and IGBT transistor, and the W-phase lower-bridge SiC transistor and IGBT transistor.

[0033] In this embodiment, the MCU implements switch configuration switching to configure different switching sequences and switch delay times; the three-phase full-bridge circuit is used for DC-AC conversion of the high-voltage battery; and the current sampling module is used to collect the U-phase, V-phase, and W-phase currents of the three-phase full-bridge circuit. The instantaneous values ​​of the three-phase currents from the motor controller are used as the basis for judgment, thereby enabling independent switching of the three-phase full-bridge circuit's switch configuration. Simultaneously, different instantaneous currents can be matched with different switch configurations to achieve optimal loss management.

[0034] The working principle is as follows:

[0035] The existing control strategies are as follows:

[0036] Existing control strategies all use the effective value of the three-phase current as the basis for switching the hybrid module switching strategy. Now, the effective current switching threshold is set to A, and the peak current is 1*1.414.

[0037] Specifically, when the three-phase sampling current exceeds A, all six transistors in the three-phase full-bridge circuit composed of the hybrid module simultaneously switch to strategy X.

[0038] When the three-phase sampling current is lower than A, all six transistors in the three-phase full-bridge circuit composed of the hybrid module simultaneously switch to the Y strategy.

[0039] This method, which synchronizes the switching strategy of the six transistors across three phases, has a major problem: the instantaneous values ​​of the three-phase currents differ even under the same effective value, reaching a maximum of 1.414 * Irms. Therefore, using the same control strategy is not optimal.

[0040] Note: Strategy X is Figure 1 The strategies for pattern A and Y are Figure 1 Mode D in this example is just an illustration; the actual mode to be used needs to be selected in conjunction with the double pulse test.

[0041] In this embodiment, the MCU signal is controlled by a TC387 control chip, the current sampling module uses a LEM standard current sensor, and the circuit diagram of the switch and logic control circuit is shown below. Figure 6 As shown, all of the above belong to the prior art, and those skilled in the art can obtain them based on the prior art, so they will not be described in detail here.

[0042] The strategy proposed in this article is as follows:

[0043] like Figure 7 As shown, the working principle is explained in detail using phase U as an example. Phase V lags by 120° and phase W lags by 240°.

[0044] Set the threshold current to ±X and the hysteresis current to ΔX;

[0045] The points where U reaches the threshold current are points A, B, C, and D (see details). Figure 4 (in Chinese annotation)

[0046] This section uses two switching methods as examples: a Y-switch control strategy is used below threshold X, and a Z-switch control strategy is used above threshold X. The actual threshold size and number can be adjusted according to the actual current.

[0047] The implementation includes the following steps:

[0048] (1) The motor controller is initially powered on. During the initial power-on, the corresponding current is detected and the Y-switch control strategy is adopted by default.

[0049] (2) Apply torque controller to normal operation and detect output current in real time;

[0050] (3) When the detected current reaches X+ΔX, i.e., point A in the figure;

[0051] (4) Switching from U-phase to Z-phase control strategy;

[0052] (5) The motor controller continues to operate;

[0053] (6) When the detected current reaches X-ΔX, i.e., point B in the figure;

[0054] (7) Switching from U-phase to Y-phase control strategy;

[0055] (8) The motor controller continues to operate;

[0056] (9) When the detected current reaches |-X-ΔX|, that is, point C in the figure;

[0057] (10) U-phase switching to Z-phase switching control strategy;

[0058] (11) The motor controller continues to operate;

[0059] (12) When the detected current reaches |-X+ΔX|, that is, point D in the figure;

[0060] (13) Control strategy for switching U phase to Y phase;

[0061] (14) Phase V adopts the same switching strategy, and lags behind Phase U by 120° overall;

[0062] (15) The W phase adopts the same switching strategy and lags behind the V phase by 120°.

[0063] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. An asynchronous control circuit for a three-phase inverter, characterized in that, include: MCU, switching and logic control circuit, current sampling module, three-phase full-bridge circuit, high-voltage bus capacitor, high-voltage battery; The current sampling module is used to collect the instantaneous value of the output current of the three-phase full-bridge circuit and feed the collected instantaneous current value back to the MCU; The MCU is connected to the switch and logic control circuit via signal connections. The switch and logic control circuit are signal-connected to the three-phase full-bridge circuit. The two ends of the high-voltage bus capacitor and the high-voltage battery are respectively connected in parallel to the voltage input terminals + and - of the three-phase full-bridge circuit.

2. The three-phase inverter asynchronous control circuit according to claim 1, characterized in that, The current sampling module collects the instantaneous values ​​of the U-phase, V-phase, and W-phase output currents of the three-phase full-bridge circuit in three separate channels.

3. The three-phase inverter asynchronous control circuit according to claim 1, characterized in that, The control signal output terminals PWM_UH, PWM_UL, PWM_VH, PWM_VL, PWM_WH, PWM_WL, Smple_UH, Smple_UL, Smple_VH, Smple_VL, Smple_WH, and Smple_WL of the MCU are respectively connected to the signal input terminals of the switch and the logic control circuit.

4. The three-phase inverter asynchronous control circuit according to claim 1, characterized in that, The signals VgsUH_SiC, VgsUL_SiC, VgeUH_IGBT, VgeUL_IGBT, VgsVH_SiC, VgsVL_SiC, VgeVH_IGBT, VgeVL_IGBT, VgsWH_SiC, VgsWL_SiC, VgeWH_IGBT, and VgeWL_IGBT of the switch and logic control circuit are respectively connected to the U-phase, V-phase, and W-phase signal input terminals of the three-phase full-bridge circuit.

5. The three-phase inverter asynchronous control circuit according to claim 1, characterized in that, The U-phase, V-phase, and W-phase signal input terminals of the three-phase full-bridge circuit include: the gate of the U-phase upper bridge SiC transistor, the gate of the U-phase upper bridge IGBT transistor, the gate of the U-phase lower bridge SiC transistor, the gate of the U-phase lower bridge IGBT transistor, the gate of the V-phase upper bridge SiC transistor, the gate of the V-phase upper bridge IGBT transistor, the gate of the V-phase lower bridge SiC transistor, the gate of the V-phase lower bridge IGBT transistor, the gate of the W-phase upper bridge SiC transistor, the gate of the W-phase upper bridge IGBT transistor, the gate of the W-phase lower bridge SiC transistor, and the gate of the W-phase lower bridge IGBT transistor.

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