A control method, device and equipment based on a bridge circuit with series switches

Abstract

The present invention discloses a control method, device, and apparatus based on a bridge circuit with series switches. Considering that when an auxiliary switch tube of an active voltage clamping circuit is turned on and a clamping capacitor is connected to a target bridge arm, the bridge arm voltage is equal to the sum of the voltage values ​​of the connected clamping capacitors, the present application controls the connection of the clamping capacitors within a dead time before the target bridge arm is turned on. Since the clamping capacitors discharge externally after connection, the greater the voltage of the clamping capacitors, the longer the time they are controlled to be connected to the target bridge arm. First, the voltage balance of each clamping capacitor is ensured. In addition, precisely because the clamping capacitors are connected for different lengths of time, the bridge arm voltage of the target bridge arm decreases in a step-like manner and drops to zero after the dead time ends, thereby reducing electromagnetic interference, reducing the requirements and volume of subsequent filter circuits, and facilitating stable and reliable operation of the circuit.

Claims

1. A control method based on a bridge circuit with switches connected in series, characterized in that: include: After the target bridge arm of the bridge circuit is turned off, obtaining a current voltage value of the clamping capacitor in each active voltage clamping circuit in the target bridge arm; dividing all the voltage values ​​arranged in numerical order into a preset number of groups; Assigning a first preset time duration, which is positively correlated with the voltage values ​​in the group, to each group of voltage values; Controlling the auxiliary switch tubes in the active voltage clamping circuit corresponding to each of the voltage values ​​to be turned on together at a moment of a second preset dead time duration before the target bridge arm is turned on, and controlling each of the auxiliary switch tubes to be turned on for its corresponding first preset time duration within the dead time; The active voltage clamping circuit is connected in parallel with each main switch in the target bridge arm in a one-to-one correspondence, and is used to clamp the voltage of the main switch corresponding to itself at a preset value.

2. The control method based on the bridge circuit with switches connected in series according to claim 1, characterized in that: The step of dividing all the voltage values ​​arranged in numerical order into a preset number of groups is specifically as follows: All the voltage values ​​arranged in numerical order are evenly divided into a preset number of groups.

3. The control method based on a bridge circuit with switches connected in series according to claim 2, characterized in that: The preset number is the total number of the main switch tubes in the target bridge arm.

4. The control method based on a bridge circuit with switches connected in series according to claim 3, characterized in that: The active voltage clamping circuit includes the auxiliary switch tube, the clamping capacitor and a diode; The first end of the auxiliary switch tube is respectively connected to the first end of the corresponding main switch tube and the anode of the diode, the second end of the auxiliary switch tube is respectively connected to the first end of the clamping capacitor and the cathode of the diode, and the second end of the clamping capacitor is connected to the second end of the corresponding main switch tube.

5. The control method based on a bridge circuit with switches connected in series according to claim 4, characterized in that: The auxiliary switch tube and the main switch tube are of the same type.

6. The control method based on a bridge circuit with switches connected in series according to claim 5, characterized in that: The auxiliary switch tube is a MOS tube.

7. The control method based on a bridge circuit with switches connected in series according to claim 1, characterized in that: The auxiliary switch tubes in the active voltage clamping circuit corresponding to each of the voltage values ​​are controlled to be turned on together at a moment of a second preset dead time before the target bridge arm is turned on, and each of the auxiliary switch tubes is controlled to be turned on for the first preset time corresponding to the dead time, specifically: The auxiliary switch tubes in the active voltage clamping circuit corresponding to each of the voltage values ​​in the group whose first preset duration is not zero are controlled to be turned on together at a moment of a second preset duration of the dead time before the target bridge arm is turned on, and each of the auxiliary switch tubes is controlled to be turned on for its corresponding first preset duration within the dead time.

8. A control device based on a bridge circuit with switches connected in series, characterized in that: include: an acquisition module, configured to acquire, after a target bridge arm of the bridge circuit is turned off, a current voltage value of a clamping capacitor in each active voltage clamping circuit in the target bridge arm; a grouping module, configured to divide all the voltage values ​​arranged in numerical order into a preset number of groups; An allocating module, configured to allocate a first preset time duration, which is positively correlated with the voltage value within the group, to each group of voltage values; a control module, configured to control the auxiliary switch tubes in the active voltage clamping circuit corresponding to each of the voltage values ​​to be turned on together at a moment of a second preset dead time duration before the target bridge arm is turned on, and to control each of the auxiliary switch tubes to be turned on for its corresponding first preset time duration within the dead time; The active voltage clamping circuit is connected in parallel with each main switch in the target bridge arm in a one-to-one correspondence, and is used to clamp the voltage of the main switch corresponding to itself at a preset value.

9. A control device based on a bridge circuit with switches connected in series, characterized in that: include: memory for storing computer programs; A processor, configured to implement the steps of the control method based on a bridge circuit with switches connected in series as claimed in any one of claims 1 to 7 when executing the computer program.

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