A zero-voltage zero-current soft switching type driving method for an ultrasonic driving unit, wherein the ultrasonic driving unit comprises a two-phase pseudo full bridge inverter circuit having soft switching capability, and a matching circuit, and the zero-voltage zero-current soft switching type driving method comprises a specific matching inductor inductance calculation step, a buffer capacitor capacitance calculation step, and a dead time and delay time calculation step;
- wherein the two-phase pseudo full bridge inverter circuit having the soft switching capability comprises six power switch tubes, which comprises a first MOS tube (Q1), a second MOS tube (Q2), a third MOS tube (Q3), a fourth MOS tube (Q4), a fifth MOS tube (Q5), a sixth MOS tube (Q6), a first buffer capacitor (CQ2), a second buffer capacitor (CQ4), a first transformer (TA) and a second transformer (TB);
- a drain of the first MOS tube (Q1), a drain of the third MOS tube (Q3) and a drain of the fifth MOS tube (Q5) are connected, and then are connected to a positive pole of a direct current bus of the two-phase pseudo full bridge inverter circuit (101);
- a source of the second MOS tube (Q2), a source of the fourth MOS tube (Q4), a source of the sixth MOS tube (Q6), one end of the first buffer capacitor (CQ2) and one end of the second buffer capacitor (CQ4) are connected, and then are connected to a negative pole of the direct current bus of the two-phase pseudo full bridge inverter circuit;
- a source of the first MOS tube (Q1), a drain of the second MOS tube (Q2), the other end of the first buffer capacitor (CQ2) and one end of a primary winding of the first transformer (TA) are connected, and an end, having the same name as the one end of the primary winding, of a secondary winding of the first transformer (TA) is used as a first voltage output end of the two-phase pseudo full bridge inverter circuit;
- a source of the fifth MOS tube (Q5), a drain of the sixth MOS tube (Q6), the other end of the second buffer capacitor (CQ4) and one end of a primary winding of the second transformer (TB) are connected, and an end, having the same name as the one end of the primary winding, of a secondary winding of the second transformer (TB) is used as a second voltage output end of the two-phase pseudo full bridge inverter circuit;
- a source of the third MOS tube (Q3), a drain of the fourth MOS tube (Q4), the other end of the primary winding of the first transformer (TA) and the other end of the primary winding of the second transformer (TB) are connected, and the other end of the secondary winding of the first transformer (TA) is connected to the other end of the secondary winding of the second transformer (TB) to form a third voltage output end of the two-phase pseudo full bridge inverter circuit;
- a voltage between the first voltage output end of the two-phase pseudo full bridge inverter circuit and the third voltage output end of the two-phase pseudo full bridge inverter circuit is used as one phase of input voltage of a two-phase motor;
- and
- a voltage between the second voltage output end of the two-phase pseudo full bridge inverter circuit and the third voltage output end of the two-phase pseudo full bridge inverter circuit is used as the other phase of input voltage of a two-phase electromagnetic motor.